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Classification of mid-seral black spruce ecosystems of northern British Columbia. Full report. Krestov, Pavel; Klinka, Karel; Chourmouzis, Christine; Kayahara, Gordon J. 2000

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CLASSIFICATION OF MID-SERAL BLACK SPRUCE ECOSYSTEMS OF NORTHERN BRITISH COLUMBIAP.V. Krestov, K. Klinka, C. Chourmouzis, and G. KayaharaForest Sciences DepartmentTHE UNIVERSITY OF BRITISH COLUMBIAMarch 2000CLASSIFICATION OF MID-SERAL BLACK SPRUCE ECOSYSTEMS OF NORTHERN BRITISH COLUMBIAbyP.V. Krestov1,2, K. Klinka2, C. Chourmouzis2, G. Kayahara21Institute of Biology and PedologyRussian Academy of Sciences, Far Eastern BranchVladivostok 690022 Russia2Forest Sciences DepartmentUniversity of British Columbia3036-2424 Main Mall, Vancouver, BC V6T 1Z4 CanadaScientia Silvica Extension SeriesNumber 26Forest Sciences DepartmentTHE UNIVERSITY OF BRITISH COLUMBIAMarch 2000Scientia Silvicais published by the Forest Sciences Department, The University of British Columbia, ISSN 1209-952XEditor: Karel Klinka (klinka@interchange.ubc.ca)Production and design: Christine Chourmouzis (chourmou@interchange.ubc.ca)Financial support: Site Productivity Working Group of the BC Ministry of ForestsiiiSUMMARYThis report presents a classification of mid-seral black spruce ecosystems in the Boreal White and Black Spruce (BWBS) and Sub-boreal Spruce (SBS) zones of British Columbia. The classification is based on a total of 122 plots sampled during the summers of 1997 and 1998. We used multivariate and tabular methods to synthesize and classify ecosystems according to the Braun-Blanquet approach and the methods of biogeoclimatic ecosystem classification. The black spruce ecosystems were classified into 8 vegetation units (associations or subassociations) and the same number of site associations. We describe vegetation and environmental features of these vegetation and site units. Vegetation and environmental tables for individual plots are given in Appendices. In addition, we also present the relationships between site index of black spruce and direct and indirect measures of site quality.ACKNOWLEDGEMENTSWe thank the following individuals: David New, David Brisco, Brad Collins, David Afleck, Katherine Zidek for field assistance and sample preparation, and Claudia Hanel for useful comments on the earlier version of the manuscript.We thank the BC Forest Service Staff from the Dawson Creek, Fort St. James, Ft. Nelson, Mackenzie, and Morice Forest Districts for assistance in locating study stands and permits for cutting site trees. We gratefully acknowledge the financial support from the Site Productivity Working Group of the BC Ministry of Forests.ivScientica Silvica Extension Series Number 26 2000TABLE OF CONTENTSSUMMARY ........................................................................................................................... iiiACKNOWLEDGEMENTS..................................................................................................... iiiINTRODUCTION.................................................................................................................. 1METHODS............................................................................................................................ 2Study Area ............................................................................................................................. 2Sampling ............................................................................................................................... 2Classification ......................................................................................................................... 4Vegetation Classification ........................................................................................... 5Similarity Analysis .......................................................................................... 6Life Form Spectral Analysis ........................................................................... 7Site Classification ...................................................................................................... 7SNR and SMR Spectal Analysis .................................................................... 8Site Index Sampling and Analysis ......................................................................................... 8RESULTS AND DISCUSSION........................................................................................... 11The Vegetation Classification .............................................................................................. 11Description of Plant Associations ........................................................................................ 19110 Picea mariana – Cladina stellaris plant association ......................................... 19120 Picea mariana – Vaccinium vitis-idaea plant association ................................. 20130 Picea mariana – Equisetum sylvaticum plant association ................................ 22210 Picea glauca & mariana – Viburnum edule plant association .......................... 24220 Picea glauca & mariana – Equisetum pratense plant association .................... 26310 Picea mariana – Betula nana plant association ............................................... 27The Site Classification ......................................................................................................... 29Description of Site Associations .......................................................................................... 36100 SbPl – Lichens site association ........................................................................ 37200 SbPl – Moss site association ............................................................................ 38300 Sb – Wood Horsetail site association ............................................................... 39400 Sb – Tamarack site association ....................................................................... 40500 SbSw – Soopolallie site association ................................................................. 41600 SbSw – Common Mitrewort site association .................................................... 42700 SbSw – Meadow Horsetail site association ...................................................... 44800 (Sb) – Swamp Birch site association ................................................................ 45Site Index in Relation to Ecological Measures of Site Quality ............................................. 46REFERENCES................................................................................................................... 52APPENDICES .................................................................................................................... 551INTRODUCTIONMid-seral Black Spruce EcosystemsINTRODUCTIONBlack spruce (Picea mariana (Mill.) B.S.P.) is a principal species of the Canadian boreal forest. While it is one of the major timber crop species in eastern Canada, in British Columbia (BC) it is considered a non- or less desirable (valuable) crop species, except on sites that are edaphically unsuitable for more desirable (valuable) crop species, such as white spruce (Picea glauca (Moench) Voss) and lodgepole pine (Pinus contorta var latifolia Dougl. ex Loud.). Its value as a crop species, however, cannot be debated in the absence of productivity data for pure and mixed-species stands of black spruce in BC. From over 2,000 reports on black spruce ecosystems published in Canada and the United States to date (TREE CD CABI, 1999), only a few have originated in the province. A better understanding of the ecology and growth of black spruce in BC is needed in anticipation of future demands for the timber resources of the boreal forest in BC.In BC, late-seral and old-growth black spruce-dominated ecosystems have been investigated by Revel (1972), Wali and Krajina (1973), and Annas (1974). More recently, the Ecological Program Staff of the BC Ministry of Forests presented a general overview of the Boreal Black and White Spruce (BWBS) and Sub-Boreal Spruce (SBS) zones (Meidinger and Pojar (1991) and a site classification for black spruce and other ecosystems in these zones (e.g. DeLong et al. 1990; MacKinnon et al., 1990; Banner et al. 1993). However, we still need additional information for a more complete understanding of these ecosystems. Therefore, we developed a classification as a complementary tool for further studies of black spruce ecosystems and as a means to relate them to other studies in the North American boreal forest. We aimed to develop a classification that organizes communities into groups in a way that shows the greatest number of vegetation and vegetation-environment relationships, is easily retained in memory, and is easily conveyed through instructions.In addition, forest managers need productivity relationships integrated into ecosystem classification. In British Columbia, measures of climate, soil moisture, nutrients, and aeration conditions have been used to relate site index (the most commonly used index of forest productivity) to site quality (Chen et al. 1998; Kayahara et al. 1998; Kayahara et al. 1997; Kayahara and Pearson 1996; Wang and Klinka 1996; Klinka and Carter 1990). To investigate black spruce ecosystems and their productivity, we carried out a study with the objectives of:(1) classifying black spruce ecosystems; (2) quantifying the relationships between black spruce site index and ecological measures of site quality; and evaluating the potential for predicting site index from easily field-estimated measures of site quality.Other aspects of black spruce growth and boreal ecology, such as height/age and site index models, a characterization of understory plant diversity, humus forms, and soil nutrient conditions of black spruce ecosystems, and a comparison of these between black spruce and trembling aspen (Populus tremuloides Michx.) ecosystems will be discussed in other reports.This report is available in full colour or B&W printed versions or in electronic format on Scientia Silvica CD-ROM. For further information or to order a copy visit www.forestry.ubc.ca/klinka or contact Karel Klinka, Forest Sciences Department, University of British Columbia, 3036-2424 Main Mall, Vancouver BC  V6T 1Z4 (e-mail:  klinka@interchange.ubc.ca).2METHODSStudy AreaScientica Silvica Extension Series, Number 26, 2000METHODS Study AreaThe study area encompassed nearly the entire BWBS zone, and the northern portion of the SBS zone, of BC. Both zones are part of the Canadian Boreal Forest Region (Krajina 1969). The BWBS zone is influenced by a continental, montane boreal climate and subject to frequent outbreaks of arctic masses. The climate influencing the SBS zone is slightly less continental, with lower temperatures in summer, higher temperatures in winter and a slightly longer growing season. Forest fires are frequent in both the SBS and BWBS zones (except for the portion of the BWBS just east of the Rocky Mountains (BWBSwk subzone)), maintaining a large portion of the landscape in early and mid-seral stages.The major species of these two zones are white spruce, hybrid white spruce (Picea engelmannii x glauca), black spruce, subalpine fir (Abies lasiocarpa (Hook.) Nutt., lodgepole pine, trembling aspen, balsam poplar (Populus balsamifera L.), paper birch (Betula papyrifera Marsh.), and Alaska paper birch (Betula neoalaskana Sarg.), with black spruce increasing in abundance with increasing latitude and with decreasing soil drainage. In mid-seral upland ecosystems, black spruce typically grows in mixtures with white spruce, hybrid white spruce, lodgepole pine, and trembling aspen. In wetlands, particularly ombotrophic wetlands, black spruce predominates and often associates with tamarack (Larix laricina (Du Roi) K. Koch). Upland soils are primarily Luvisols, Podzols, Brunisols, and Gleysols, while organic soils are associated with wetlands – bogs, fens, marshes, and swamps. More detailed information about the BWBS and SBS zones is given in Krajina (1969) and Meidinger and Pojar (1991).SamplingThe ecosystem sampling was done during the summers of 1997 and 1998. In the first season, we (i) carried out a reconnaissance, (ii) located candidate ecosystems for sampling, and (iii) described and sampled about 70 plots. During the second season we completed the description and sampling of selected ecosystems and cut nearly 400 trees for stem analysis. Our data set includes vegetation and environmental information obtained from 122 plots. The candidate ecosystems were located close to access roads branching from the Cassiar and Alaska Highways, around Tumbler Ridge, and north of Fort St. James (Figure 1). They were deliberately selected to obtain the (i) the widest possible range in environmental conditions (climate, soil moisture, soil nutrients, and soil aeration), and (ii) height growth data from trees without a history of suppression. Suitable stands were typically found on sites that had an obvious history of wildfire. We assumed that the original advance regeneration was destroyed by fire, and the subsequently established seedlings had developed under full light conditions, except during the earliest developmental stages (<1.3 m in height), in which the seedlings might have been affected by competing shrubs and tall herbs. All selected stands had a uniform single canopy layer dominated by black spruce, which was often associated with lodgepole pine, white spruce, hybrid spruce, or trembling aspen.3METHODSSamplingMid-seral Black Spruce Ecosystems Figure 1. The native range of black spruce in British Columbia and the distribution of sample plots. Distribution frequencySample plotsinfrequentfrequentvery frequentisolated standplot locationnumber of plots at a location(2)(2)(7)(4)(3)(6)(6)(9)(3)(3)(4)(6)(8)(11)(5)4METHODSClassificationScientica Silvica Extension Series, Number 26, 2000Sample plots, each 20 x 20 m (0.04 ha) in size, were located in naturally established, unmanaged, immature and early mature (>35 but <185 years at breast height), even-aged stands (the age range of all sampled trees was <20 years in each stand (Smith 1986)). Each sample plot was selected to represent an ecosystem that was relatively uniform in stand structure, floristic composition, and site attributes (e.g., slope position, aspect, gradient, soils and ground cover). The biogeoclimatic subzone or variant was identified using biogeoclimatic maps for the Prince Rupert Region (BC Ministry of Forests 1998), and for the Prince George Region (BC Ministry of Forests, 1987). Latitude and longitude were determined from topographic maps, and elevation was measured with a Thommen pocket altimeter. Site, vegetation, and soil of each plot were described according to Luttmerding et al. (1990).All plant species present within the plot were identified and their cover percentage was estimated. These cover values were converted to classes (+ to 9) of the Domin-Krajina scale of species significance. The plant nomenclature followed Qian and Klinka (1998). Unknown plants were collected and identified in the laboratory. A soil pit was dug at each plot and soils were described and identified according to the Canadian Soil Classification System (Agriculture Canada Expert Committee on Soil Survey 1987). Humus samples were taken from each plot for a visual analysis and identification in the laboratory using the humus form classification of Green et al. (1993). The type of ground cover (forest floor, decaying wood, mineral soil, coarse fragments, and open water) was recorded. A more complete description of the field methods is given in Brooke et al. (1970) and Luttmerding et al. (1990). Soil moisture and nutrient regimes were estimated in the field by a systematically guided evaluation of a selected number of topographic (slope, aspect, gradient, and position) and soil morphological properties (humus form, rooting depth, soil texture, coarse fragment content, soil aeration, soil mineralogy, and the presence and depth of the growing-season water table). This procedure is based on interpreting relationships between these properties, soil water-holding capacity, and available nutrient levels in the soil (Green and Klinka 1994). Field-estimates of SNRs were substantiated by soil nutrient analysis (Kayahara et al. 2000, submitted manuscript), while SMRs were only field-estimated and not directly measured. Using the criteria proposed by Klinka et al. (1989), we converted relative SMRs to actual SMRs by consulting Wang et al. (1994) for the SBSdk subzone and Banner et al. (1993) for the BWBSdk subzone. Conversion for the BWBmw and BWBSwk subzones was done on the basis of our environmental data, indicator plant analysis, correlation with the other subzones in this study, and with the estimates of actual SMRs for the SBS subzones given by Kayahara et al. (1995, unpublished report).ClassificationOur objective was to produce ecologically meaningful classes of ecosystems that could be identified and used as a framework for examining vegetation-environment relationships. Consistent with the methods of the biogeoclimatic ecosystem classification, the plots within each group had to represent communities that had affinities in floristic composition and physiognomy, and the groups of plots were required to 1) be floristically distinct, and 2) occupy a floristically defined segment of the edaphic and local climatic gradients. The classification was done in the following sequence: 1) vegetation classification, and 2) site classification using the results of the vegetation classification, spectral analysis, and the environmental data.5METHODSClassificationMid-seral Black Spruce EcosystemsVegetation ClassificationWe classified the ecosystems into vegetation units at three categorical levels (subassociation, association, and alliance) using the Braun-Blanquet approach (Mueller-Dombois and Ellenberg 1974: 177-210; Westhoff and van der Maarel 1980: 287-399). This method consists of grouping the plots in a way that each group is separated from all other groups by an exclusive diagnostic combination of species. These diagnostic species must be either differential species, which have a much higher presence (proportion of plots of a group that it occurs in) than in other groups, or a dominant differential species, which have higher species significance (percent cover) than in other groups. The exact criteria are as follows (Becking 1957):differential species: species that may be associated with more than one vegetation unit in a hierarchy; presence class ≥ III (occurring in ≥ 40% of the plots of this unit) and at least two presence classes greater than in other units of the same hierarchical level within the same higher level unit. dominant-differential species: species that may be associated with more than one vegetation unit in a hierarchy; presence class ≥ III, mean species significance ≥ 5 (≥ 10% cover) and two or more species significance classes greater than in other units of the same hierarchical level within the same higher level unit.There is no universally accepted methodology for, nor agreement upon, the required composition of the diagnostic combination of species for a particular category (Becking 1957; Mueller-Dombois and Ellenberg 1974; Westhoff and van Maarel 1980). We used the principle of relative differentiation that allows delineation of a subassociation or association by an exclusive diagnostic combination of species that must include at least one differential species or dominant-differential species. However, a subassociation or association that represents the central concept, i.e. typic, of a higher circumscribing unit can be recognized without a diagnostic combination of species because it is differentiated by the absence or low occurrence of species that characterize other subassociations or associations of the same hierarchical level within the same higher level unit (Pojar et al. 1987: 131-132). The major tool used to achieve this objective was a computer-aided program, VTAB-Ecosystem Reporter, Revision 19907a (Emanuel 1999), which produces the various tables required in the analysis and synthesis of vegetation data. It arranges columns (plots or groups of plots) and rows (species) according to the criteria specified by the user for each step of the tabular analysis and synthesis.The following four analytical steps were used to synthesize the data:Step 1 Plots were stratified into floristically similar groups using a two-way indicator species analysis (TWINSPAN, Hill 1979). This program divides the plots into two groups, then further subdivides each of these groups in subsequent steps. When all the plots in a group are relatively uniform according to predetermined criteria, subdivision of this group stops.Step 2 For each of the groups obtained in step 1, a tentative vegetation plot table, which shows the species significance of each species in all plots of the group (e.g., Appendices 3 through 9), was produced and examined for within-group similarities and differences. A tentative differentiated summary vegetation table (e.g., Table 3), showing species presence and average species significance for each group, was used to examine floristic affinities and differences between groups. 6METHODSClassificationScientica Silvica Extension Series, Number 26, 2000Step 3 Tentative environmental plot tables, which show selected environmental characteristics for all plots within each group (e.g., Appendices 10 through 16), were used to determine whether the floristically similar plots were also similar in environmental characteristics. Floristically and environmentally aberrant plots were reassigned to the group to which they were most closely related. After reassignment, the summary vegetation tables were inspected to determine to which extent the groups of plots could be differentiated from each other in a hierarchical manner. The groups that could not be differentiated were merged. Steps 2 and 3 were repeated iteratively in a process of successive approximation (Poore 1962), in which the production of revised vegetation and environmental tables continued until there were no more plot re-assignments and group mergers. Step 4 A tentative hierarchy of groups was then proposed, where each group was considered to be either an association or a subassociation depending on its relationship to the hierarchy. A preliminary diagnostic table showing the diagnostic combination of species for every group was produced. Step 4 was repeated in a process of successive approximations in which the production of tentative diagnostic tables continued until exclusive diagnostic combinations of species were obtained for each group of the hierarchy. This process typically required changes in the structure of the hierarchy, and, occasionally, merging of some of the groups lacking a diagnostic combination of species.Instead of using phytosociological nomenclature (Barkman et al. 1976) we used the scientific names without suffixes for naming vegetation units. Plant alliances and associations were named using the generic and specific names of two dominant species from the diagnostic combination of species for that association, e.g., the Picea mariana – Cladina stellaris plant association. Plant subassociations were named by adding a colon (:) to the association name, followed either by the term ‘typic’ (to represent what we believed to be the central concept of that association) or the name of one diagnostic species, e.g., the Picea mariana – Equisetum sylvaticum: Larix laricina plant subassociation. All units based on the synthesis of <10 sample plots were considered tentative.Similarity Analysis Using VTAB, we compared floristic similarities between each pair of vegetation units using Sørenson’s index based on presence/absence of species (Equation 1, Magurran 1988), as well as on species cover (Equation 2, Qian et al. 1997). The presence/absence index is a simple but effective measure of the number of species shared between two vegetation units. Both indices enable the comparison of floristic similarity between vegetation units. Equation 1. , where a = the number of species in the first unit, b = the number of species in the second unit,  c = the number of species common to both units.  Equation 2. , where A = the cover sum of all species in the first unit,B = the cover sum of all species in the second unit,  C = the sum of the lower of the two cover values for the species common to both units.SI2cab+()-----------------=SI2CAB+()------------------=7METHODSClassificationMid-seral Black Spruce EcosystemsLife Form Spectral AnalysisTo provide a simple means for characterizing the vegetation of a group of plots complementary to tabular analysis, VTAB-assisted ‘spectral analysis’ was carried out (Mueller-Dombois & Ellenberg 1974:315-319). In spectral analysis, species are grouped according to various criteria. For each vegetation unit, the cover proportion of these groups of species relative to all species of interest is calculated. This relative proportion is termed relative frequency hereafter. Spectral analysis was performed on life forms (coniferous trees, broad-leaved trees, evergreen shrubs, deciduous shrubs, ferns, graminoids, herbs, mosses, liverworts, lichens and dwarf woody plants). A spectrum was constructed for each vegetation unit, representing the relative frequency of each life form in that vegetation unit. Relative frequencies were calculated using Equation 3 (Klinka et al. 1996). The plots were not standardized, i.e., plots with a greater total vegetation cover contribute relatively more to the spectrum of the vegetation unit.Equation 3. , whereSite Classification A site is a portion of the landscape with relatively uniform climatic and edaphic characteristics. Similar sites will have similar vegetation potential and productivity, and will respond similarly to management. Therefore, an important purpose of ecosystem classification is to frame site units that (i) can form a framework in which to investigate site-productivity relationships and (ii) are easily identifiable in the field, even when they are not vegetated (e.g. clearcuts).In addition to the ecological site characteristics, the vegetation at a site reflects the history of disturbance, the time since the last disturbance, the characteristics of the tree layer, and chance. Therefore, several different vegetation types can exist on similar sites, and vegetation units derived from different seral stages cannot form the basis of a convenient and stable framework for site classification. Of all seral stages, the old-growth vegetation is considered to best reflect site quality, and to be minimally influenced by disturbance history. We suggest that the vegetation of the mid-seral black spruce stands is similar enough to the old-growth stands that a site classification could be derived. In addition, site index is preferably derived from non-supressed trees in even-aged mid-seral stands. The basic category of site classification is the site association. Sites that have, regardless of the actual vegetation, the same or equivalent environmental properties and, hence, similar vegetation and productivity potentials are grouped into a site association. In this study, site associations were derived from mid-seral plant associations and characterized by climate (biogeoclimatic subzones or variants), soil moisture regime (SMR), and soil nutrient regime (SNR). To create edaphically uniform classes of ecosystems, we divided site associations into site types according to one or more edaphic factors or properties that are thought to be important in affecting ecosystems. FjCii 1=n∑Ciji 1=n∑j 1=m∑---------------------------=  = relative frequency (%) of species group j (j = 1,2,3...m) for lifeform (m= 12), and = midpoint percent cover value of species i (i= 1,2,3...n).FjCi8METHODSSite Index Sampling and AnalysisScientica Silvica Extension Series, Number 26, 2000We named site associations by the common names of one or two dominant tree species and an indicator plant species, or life form, which is expected to be nearly always present on the sites represented by the site association (e.g., the SbSw – Common Mitrewort site association). Tree species names were abbreviated using the standard symbols of the BC Ministry of Forests (Pl = lodgepole pine; Sb = black spruce; Sw = white spruce; At = trembling Aspen; Lt = tamarack ). The subdivisions of site association based on edaphic factors, i.e. the site types, were named by modifying the name of a site association by one or two diagnostic adjectives, e.g., SbSw – Common Mitrewort/organic site type. We used the diagnostic adjective typic for the site type thought to represent the central edaphic concept of the site association, and other adjectives to denote aberrant edaphic properties, i.e. those differing from typic. SNR and SMR Spectal AnalysisTo characterize the soil moisture and nutrient status of each site association, a soil nutrient spectrum and a soil moisture spectrum were constructed.  A spectrum presents the relative frequency of each indicator species group in that site association. Relative frequencies were calculated using Equation 3 (for the attribute SMR (m= 6), and SNR = (m= 3)). We used the mean relative frequency of the nitrogen-rich indicator species group to determine soil nutrient regime as follows: 1% for very poor SNR, 4% for poor SNR, 9% for medium SNR, 25% for rich SNR, and 38% for very rich SNR (Wang 1992).Site Index Sampling and AnalysisIn each sample plot, the three largest diameter and dominant trees without visible evidence of growth abnormalities and damage were felled for stem analysis. Total tree height was measured in the field after falling. Stem disks were cut at 0.3, 0.8 and 1.3 m above the ground surface, and then at 1-m intervals from 1.3 m to the top of the tree. In the laboratory, each disc was cut sliced transversely with a sharp knife, and, when necessary, zinc oxide powder was added to make the rings more visible. Rings were counted in two directions with the aid of a microscope. Particular attention was paid to abrupt changes in radial increment to detect possible suppression.The raw stem analysis data were adjusted using Carmean’s (1972) algorithm to calculate tree height corresponding to the age at each sectioned disk (Dyer and Bailey 1987). The height versus age curves for the three trees in each sample plot were examined for uniformity and the presence of suppression. If suppression was present or suspected, the three breast height disks were compared with each other for differences in the radial increment pattern. If a tree was considered suppressed, it was excluded and the remaining two trees per plot were used in further analysis. If more than one tree showed suppression, the plot was excluded from the analysis. Trees <50 years at breast height were also excluded. Of the 122 study plots, 82 were used for stem analysis; 36 were excluded due to suppression of trees, and 4 did not meet the minimum index age of 50 years at breast height.Site index reflects the integrated effect of site factors on tree growth. Since the site index concept is applied at the stand scale (Monserud 1984; Nigh and Sit 1996; Chen et al. 1998), averaging was used to obtain a single height growth curve for each stand. Linear interpolation (Carmean 1975; Nigh 1996) was used to obtain an average height-age curve. Height-age data were averaged by plot for each selected age up to the youngest tree. The site index for each plot was calculated as the average top height of the sampled trees at breast height age 50 years.Correlation analysis was perfomed to detect relationships between site index and elevation, latitude, longitude, and slope. Analysis of variance (ANOVA) was used to test for differences in mean site index between (1) the BWBS and SBS zone, and between 9METHODSSite Index Sampling and AnalysisMid-seral Black Spruce Ecosystemsthree subzones within the BWBS zone; (2) soil orders; (3) soil moisture regimes; (4) soil nutrient regimes; (5) aspect classes and (6) site associations. Tukey’s test was used for multiple comparisons. In each ANOVA, only classes with more than one plot were included. Multiple regression models with site index as the dependent variable were developed using the independent variables (1) elevation, (2) elevation and latitude; (3) soil order and elevation; (4) SMR and elevation; (5) SNR and elevation; (6) SMR, SNR, and elevation; and (7) site association and elevation. Additionally, the regressions using soil moisture and nutrient regimes together were tested with and without soil moisture by nutrient interactions. All regressions, except (1) and (2), were also tested without elevation as an independent variable. Dummy variables were used for the categorical variables of soil orders, soil moisture/nutrient regimes, and site associations. To make the regressions comparable, the four plots with a unique soil moisture/soil nutrient combination were excluded from this analysis, for N=78 plots. The mean site index for the combinations of soil moisture and nutrient regimes was calculated with corresponding confidence and prediction intervals.10METHODSSite Index Sampling and AnalysisScientica Silvica Extension Series, Number 26, 200011RESULTS AND DISCUSSIONThe Vegetation ClassificationMid-seral Black Spruce EcosystemsRESULTS AND DISCUSSIONThe Vegetation ClassificationA list of all species found in the sample plots is given in Appendix 1. The list is representative of the flora of mid-seral black spruce ecosystems, but is not a complete list for black spruce ecosystems in general, as the early- and late-seral succession stages were not studied. All 122 sample plots were classified into a hierarchy of vegetation units that includes 3 alliances, 6 associations, and 4 subassociations (Table 1). These units were delineated according to floristic differences (diagnostic combinations of species) that are summarized in Table 2.  Table 3 lists all species occurring in ≥ 41% of the plots in at least one vegetation unit (presence class ≥ III), while those species occurring in ≤ 40% of the plots of all vegetation units (presence class ≤ II) are listed in Appendix 2.  Eight units, either associations or subassociations, were most fundamental, i.e. not further subdivided, and these eight units are referred to as the basic units hereafter. Vegetation plot tables, which show the species significance of each species in all sample plots of each basic unit (110 to 310) are given in Appendices 3 to 9.All units, except the provisional Picea mariana – Betula nana (310) association, are thought to belong to the Picea glauca & mariana order that was proposed by Krajina (1969) to represent montane boreal ecosystems. He proposed Picea glauca, P. mariana, Abies lasiocarpa, Larix laricina, Pinus banksiana, P. contorta, and Populus tremuloides as the characteristic species of this order. All these species are present in our data set (Appendix 1), except for Pinus banksiana whose range is outside the study area.Table 1.  Synopsis of vegetation units delineated in mid-seral black spruce ecosystems indicating levels of generalization and relationships. The rows containing the names of associations are printed in bold fonts. Numerical codes indicate the position of a unit in the hierarchy; the same codes are used in the diagnostic and summary vegetation tables. An asterisk indicates an insufficiently sampled unit (<10 plots). Code Plant alliancePlant associationPlant subassociation100 Picea mariana – Vaccinium vitis-idea110 Picea mariana – Cladina stellaris* (5 plots)120 Picea mariana – Vaccinium vitis-idaea (25 plots)130 Picea mariana – Equisetum sylvaticum131 Picea mariana – Equisetum sylvaticum: typic (34 plots)132 Picea mariana – Equisetum sylvaticum: Larix laricina (13 plots)200 Picea glauca & mariana – Lonicera involucrata210 Picea glauca & mariana – Viburnum edule211 Picea glauca & mariana – Viburnum edule: Shepherdia canadensis (13 plots)212 Picea glauca & mariana – Viburnum edule: Mitella nuda (28 plots)220 Picea glauca & mariana – Equisetum pratense* (3 plots)300 Betula nana310 Picea mariana – Betula nana* (1 plot)12RESULTS AND DISCUSSIONThe Vegetation ClassificationScientica Silvica Extension Series, Number 26, 2000Table 2. Diagnostic combinations of species for the vegetation units in mid-seral black spruce ecosystems. The diagnostic combination of species for each vegetation unit is shaded in gray. Presence values ≥III are printed in bold fonts. An asterisk indicates an insufficiently sampled unit (<10 plots).Vegetation unit code 110 120 131 132 211 212 220 310Number of plots 5 25 34 13 13 28 3 1SpeciesDiagnosticvalue1Species presence2 and species significance3100 Picea mariana – Vaccinium vitis-idea allianceDicranella palustris  (ic)1II233II h I + III + I h I +Empetrum nigrum (ic) II 4 III 3 II 2 II 2 I hLedum groenlandicum (d) III 1 IV 5 V 5 IV 6 I + II 4 V 4Peltigera membranacea (ic) III 4 III 2 III + I h I 1 II +Pinus contorta (ic) V 7 IV 7 III 6 II 4 III 6 III 5Vaccinium scoparium (ic) II 2 II 2 I 3 I h I +Vaccinium vitis-idaea (d) V 5 IV 5 V 5 V 4 I h III 3 II hVaccinium uliginosum (ic) I 1 I h I + II 2110 Picea mariana – Cladina stellaris association*Arctostaphylos uva-ursi (ic) II 4 I +Cladina stellaris (d) V 6 III 4 II + II + I 2 I h II hCladonia ecmocyna (ic) III + II h I h I h I h I h II hNephroma arcticum (ic) II h I hStereocaulon paschale (ic) II 5 I h120 Picea mariana – Vaccinium vitis-idaea associationOrthilia secunda (ic) III + II h I h II h III + IV +130 Picea mariana – Equisetum sylvaticum associationEquisetum sylvaticum (d) I h III 3 IV 4 II + II h II 5131 Picea mariana – Equisetum sylvaticum; typic subassociationPeltigera membranacea (d) III 4 III 2 III + I h I 1 II +Pinus contorta (dd) V 7 IV 7 III 6 II 4 III 6 III 5132 Picea mariana – Equisetum sylvaticum; Larix laricina subassociationAulacomnium palustre (d) I 2 I + II 1 IV 4 I + IV 5Dicranella palustris (d) II 3 II h I + III + I h I +Larix laricina (d) I 4 III 5 I + I 4 II hRubus chamaemorus (d) I + III 4 I tRubus pedatus (d) I h I h III 1 II 3 II +200 Picea glauca & mariana – Lonicera involucrata allianceArnica cordifolia (ic) II + I h III 1 II + II hAster ciliolatus (ic) I h III 2 II h II hDelphinium glaucum (ic) I t I t I h I h II h II +Heracleum maximum  (ic) I + I h II 2Lonicera involucrata (d) II h I h I 3 III 2 IV 4 V 4Osmorhiza berteroi  (ic) I t I h III h II h II +Petasites frigidus (ic) III 1 III 2 II 1 III 2 IV 3 V 4Picea glauca (d) II 4 II 5 II 4 I 4 V 6 IV 7 IV 6Rosa acicularis (d) III + III 2 III 2 III 2 V 2 V 2 IV 4Ribes lacustre (ic) I h I h I h II h III 1 II +Rubus pubescens (ic) I h I + III 3 III 2 IV 2 V 5210 Picea glauca & mariana – Viburnum edule associationAbies lasiocarpa (ic) II 4 I 3 I 4 III 4 II 4Actaea rubra (ic) I h II 1 II +Amelanchier alnifolia (ic) II 2 I hEpilobium angustifolium (d) I h II + II 2 II h V 2 IV 2 II +Fragaria virginiana (ic) I h I h III + II hGalium boreale (ic) I h I h I + III + II hGalium triflorum (ic) II h II +13RESULTS AND DISCUSSIONThe Vegetation ClassificationMid-seral Black Spruce EcosystemsPinus contorta (d) V 7 IV 7 III 6 II 4 III 6 III 5Populus tremuloides (d) I h I 1 I 3 III 7 III 5Viburnum edule (d) II h I h I 2 IV 3 IV 2211 Picea glauca & mariana – Viburnum edule; Sheperdia canadensis subassociationGeocaulon lividum (d) II 1 III 2 II + II h IV 3 II hMaianthemum racemosum  (d) I t III + I +Populus tremuloides (dd) I h I 1 I 3 III 7 III 5Shepherdia canadensis (d) I h II 3 I + I + IV 4 II 2212 Picea glauca & mariana – Viburnum edule; Mitella nuda subassociationAchillea millefolium (d) I h I h I h I h III hMertensia paniculata (d) I + II h II + I + II + IV 1 V 3Mitella nuda (d) I h II h I h II h V 1 V 1Vaccinium vitis-idaea (d) V 5 IV 5 V 5 V 4 I h III 3 II h220 Picea glauca & mariana – Equisetum pratense association*Angelica genuflexa (d) I h V 3Aulacomnium palustre (d) I 2 I + II 1 IV 4 I + IV 5Carex disperma (d) I t I h II 1 I + IV 5Disporum hookeri (d) I h I h IV +Equisetum pratense (d) I t II + II 2 I h II + V 7Equisetum scirpoides (d) I h II + II h I h II 2 IV 1Geum macrophyllum (d) IV 3Impatiens noli-tangere (ic) II hListera cordata (d) I t I h I h II h IV +Moneses uniflora (d) I h I h I h I h II h IV +Oxycoccus oxycoccos (d) I h I + I 3 I + IV +Parnassia palustris (ic) I t II hPlagiochila aspleniformis (ic) I h II +Ranunculus eschscholtzii (ic) II hRhizomnium glabrescens  (d) II 2 I t IV 4Ribes triste (d) I h I h I h I h II + IV +Salix glauca (d) I + I 2 I 2 I 2 IV 3Senecio triangularis (d) I h IV +Sphagnum girgensohnii (d) II 4 I 4 I t IV 6310 Picea mariana – Betula nana association*Betula nana  (d) I 1 I 1 II 3 I h V 7Comandra umbellata (d) V 5Drepanocladus exannulatus (d) V +Drepanocladus uncinatus (d) I t I h I t V 4Equisetum fluviatile (d) I h I t V 4Eriophorum angustifolium (d) V 6Eurhynchium pulchellum (d) V +Menyanthes trifoliata (d) V 5Plagiomnium ellipticum (d) V +Sphagnum warnstorfii (d) I h I + I 3 I + II h V 7Tomentypnum nitens (d) II 4 I h V 61. Species diagnostic values: d = differential, dd = dominant differential, ic = important companion (Pojar et al. 1987).2. Species presence classes (the percentage of plots in which the species occurs): I = 1-20%, II = 21-40%, III = 41-60%, IV = 61-80%, V = 81-100%.3. Species significance classes and the corresponding mid-point and range (in parentheses) of cover: t = 0.005 (0.001-0.009), h = 0.05 (0.01 - 0.099), + = 0.2 (0.1-0.299), 1 = 0.4 (0.3-0.499), 2 = 0.75 (0.5-0.999), 3 = 1.5 (1-1.999), 4 = 3.5 (2-4.999), 5 = 7.5 (5-9.999), 6 = 15 (10-19.999), 7 = 35 (20-49.999), 8 = 60 (50-69.999), 9 = 85 (70-100).Vegetation unit code 110 120 131 132 211 212 220 310Number of plots 5 25 34 13 13 28 3 1SpeciesDiagnosticvalue1Species presence2 and species significance314RESULTS AND DISCUSSIONThe Vegetation ClassificationScientica Silvica Extension Series, Number 26, 2000Table 3. Differentiated (in descending order from left to right) summary table of the vegetation units in mid-seral black spruce ecosystems. This table contains only plant species present in ≥41% of the plots in at least one vegetation unit (presence class ≥III). As most of these species were diagnostic (differential, dominant-differential, and important companion species, Table 2) for a vegetation unit, only non-diagnostic species are shaded in grey. Presence values ≥III are printed in bold fonts.Vegetation unit code 110 120 131 132 211 212 220 310Number of sample plots 5 25 34 13 13 28 3 1Number of  plant species 52 129 128 108 107 152 68 16Species Species presence1 and species significance2Cladonia ecmocyna III + II h I h I h I h I h II hCladina stellaris V 6 III 4 II + II + I 2 I h II hPeltigera membranacea III 4 III 2 III + I h I 1 II +Ledum groenlandicum III 1 IV 5 V 5 IV 6 I + II 4 V 4Pinus contorta V 7 IV 7 III 6 II 4 III 6 III 5Vaccinium vitis-idaea V 5 IV 5 V 5 V 4 I h III 3 II hLinnaea borealis III + III 1 III 1 II 1 IV 1 IV 4 II 2 V 3Hylocomium splendens III 6 V 7 V 7 V 7 IV 7 V 7 V 7Rosa acicularis III + III 2 III 2 III 2 V 2 V 2 IV 4Picea mariana V 7 V 7 V 7 V 7 IV 7 V 7 V 7 V 6Pleurozium schreberi IV 7 V 7 V 7 V 7 V 7 V 7 V 7 V 4Empetrum nigrum II 4 III 3 II 2 II 2 I hGeocaulon lividum II 1 III 2 II + II h IV 3 II hOrthilia secunda III + II h I h II h III + IV +Peltigera aphthosa III 3 V 3 IV 1 II 1 III 1 II 2Cornus canadensis II 1 V 4 IV 5 IV 3 V 4 V 5 II 5Petasites frigidus III 1 III 2 II 1 III 2 IV 3 V 4Ptilium crista-castrensis IV 6 IV 5 IV 4 III 5 IV 6 IV 7Equisetum sylvaticum I h III 3 IV 4 II + II h II 5Dicranella palustris II 3 II h I + III + I h I +Larix laricina I 4 III 5 I + I 4 II hRubus chamaemorus I + III 4 I tRubus pedatus I h I h III 1 II 3 II +Aulacomnium palustre I 2 I + II 1 IV 4 I + IV 5Abies lasiocarpa II 4 I 3 I 4 III 4 II 4Arnica cordifolia II + I h III 1 II + II hAster ciliolatus I h III 2 II h II hFragaria virginiana I h I h III + II hGalium boreale I h I h I + III + II hMaianthemum racemosum  I t III + I +Osmorhiza berteroi  I t I h III h II h II +Shepherdia canadensis I h II 3 I + I + IV 4 II 2Epilobium angustifolium I h II + II 2 II h V 2 IV 2 II +Populus tremuloides I h I 1 I 3 III 7 III 5Viburnum edule II h I h I 2 IV 3 IV 2Lonicera involucrata II h I h I 3 III 2 IV 4 V 4Picea glauca II 4 II 5 II 4 I 4 V 6 IV 7 IV 6Rubus pubescens I h I + III 3 III 2 IV 2 V 5Achillea millefolium I h I h I h I h III hRibes lacustre I h I h I h II h III 1 II +Mertensia paniculata I + II h II + I + II + IV 1 V 3Mitella nuda I h II h I h II h V 1 V 1Angelica genuflexa I h V 3Carex disperma I t I h II 1 I + IV 5Disporum hookeri I h I h IV +Equisetum pratense I t II + II 2 I h II + V 7Equisetum scirpoides I h II + II h I h II 2 IV 1Geum macrophyllum IV 3Listera cordata I t I h I h II h IV +Moneses uniflora I h I h I h I h II h IV +15RESULTS AND DISCUSSIONThe Vegetation ClassificationMid-seral Black Spruce EcosystemsOxycoccus oxycoccos I h I + I 3 I + IV +Rhizomnium glabrescens  II 2 I t IV 4Ribes triste I h I h I h I h II + IV +Salix glauca I + I 2 I 2 I 2 IV 3Senecio triangularis I h IV +Sphagnum girgensohnii II 4 I 4 I t IV 6Betula nana  I 1 I 1 II 3 I h V 7Bryum spp.  I t V +Comandra umbellata V 5Drepanocladus exannulatus V +Drepanocladus uncinatus I t I h I t V 4Equisetum fluviatile I h I t V 4Eriophorum angustifolium V 6Eurhynchium pulchellum V +Menyanthes trifoliata V 5Plagiomnium ellipticum V +Sphagnum warnstorfii I h I + I 3 I + II h V 7Tomentypnum nitens II 4 I h V 61. Species presence classes (the percentage of plots in which the species occurs): I = 1-20%, II = 21-40%, III = 41-60%, IV = 61-80%, V = 81-100%.2. Species significance classes and the corresponding mid-point and range (in parentheses) of cover: t = 0.005 (0.001-0.009), h = 0.05 (0.01 - 0.099), + = 0.2 (0.1-0.299), 1 = 0.4 (0.3-0.499), 2 = 0.75 (0.5-0.999), 3 = 1.5 (1-1.999), 4 = 3.5 (2-4.999), 5 = 7.5 (5-9.999), 6 = 15 (10-19.999), 7 = 35 (20-49.999), 8 = 60 (50-69.999), 9 = 85 (70-100).Vegetation unit code 110 120 131 132 211 212 220 310Number of sample plots 5 25 34 13 13 28 3 1Number of  plant species 52 129 128 108 107 152 68 16Species Species presence1 and species significance216RESULTS AND DISCUSSIONThe Vegetation ClassificationScientica Silvica Extension Series, Number 26, 2000While the constant occurrence of Picea mariana was a consequence of the sampling design, many other species, such as Linnaea borealis, Hylocomium splendens, Pleurozium schreberi, Geocaulon lividum, Peltigera aphthosa, Cornus canadensis, and Ptilium crista-castrensis, also occurred in all or nearly all groups (Table 3). This resulted in the somewhat poor floristic differentiation reflected by both the numerical and tabular analyses. Some other species that were used in diagnostic combinations of species had marginal differential values (e.g. Rosa acicularis) or could be used only as important companions, (e.g. Empetrum nigrum, an important companion for the Picea mariana – Vaccinium vitis-idaea alliance, or Petasites frigidus, an important companion species for the Picea glauca & mariana – Lonicera involucrata alliance) (Table 2).One plot was very different from all others, and was tentatively placed as the Picea mariana – Betula nana association in the Betula nana alliance (Table 1). Among all other plots, a distinct subdivision was present and we considered these two groups to be alliances: Picea mariana – Vacinium vitis-idaea, and Picea glauca & mariana – Lonicera involucrata. The former is distinguished by the presence of ericaceous shrubs and is often found on nutrient poor soils, while the latter is distinguished by a higher presence of white spruce, deciduous shrubs, and herbs, and is often found on nutrient-medium and richer soils ( Table 2). The Picea mariana – Vacinium vitis-idaea alliance includes three associations, which are, in order of increasing soil moisture: Picea mariana – Cladina stellaris (110), Picea mariana – Vaccinium vitis-idaea (120), and Picea mariana – Equisetum sylvaticum (130) (Table 1). Of all vegetation units recognized in this report, the Picea mariana – Vaccinium vitis-idaea (120) association is most poorly differentiated from the others (Table 2) as it represents intermediate soil moisture (slightly dry) and poor soil nutrient conditions. Communities of the Picea mariana – Vaccinium vitis-idaea (120) association occur typically on zonal sites across the BWBS zone. Earlier successional stages are characterized by a higher presence of lodgepole pine and lichens; later successional stages are characterized by an increasing presence of Equisetum sylvaticum. Two subassociations of the Picea mariana – Equisetum sylvaticum (130) association were delineated: (i) typic, often including lodgepole pine, and (ii) Larix laricina, often including tamarack (Table 3).The Picea glauca & mariana – Lonicera involucrata alliance includes two associations which are, in order of increasing soil moisture: Picea glauca & mariana – Viburnum edule (210), and Picea glauca & mariana – Equisetum pratense (220) (Table 1). The Shepherdia canadensis (211) and Mitella nuda (222) subassociations of the Picea glauca & mariana – Viburnum (210) edule association signify differences in soil moisture, with the former occupying drier and warmer sites than the latter (Table 2). Communities of the Picea glauca & mariana – Lonicera involucrata (200) alliance are influenced by a fluctuating growing-season water table, which is typically found in fine-textured, lacustrine soils. Compared to the Picea mariana – Equisetum sylvaticum (130) association, communities of the tentative Picea glauca & mariana – Equisetum pratense (220) association are associated with nutrient-medium and richer organic soils.The tentative Picea mariana – Betula nana (310) association represents ecosystems that are wetter than those included into the Picea mariana – Equisetum sylvaticum (130) and Picea glauca & mariana – Equisetum pratense (220) associations, and could be considered to be transitional between forested and non-forested ecosystems (Table 3). Since this association is represented by only one sample plot, the species significance values can be found in Table 3 and Appendix 2.The floristic individuality of the vegetation units was described by two sets of similarity indices (Table 4). The tentative Picea mariana – Betula nana (310) association was most dissimilar to other units, followed by the Picea mariana – Cladina stellaris (110) and Picea glauca & mariana – Equisetum pratense (220) associations, two units with contrasting edaphic properties, the former drier and poorer, the latter wetter and richer than the majority of the units. All other units had relatively high similarities to each other according to both indices. Two pairs were consistently most similar: (i) the Picea mariana – Vaccinium vitis-idaea (120) association and the Picea mariana – Equisetum sylvaticum: typic (131) subassociation, and (ii) the Picea mariana – Equisetum sylvaticum: typic (131) subassociation and the Picea glauca & mariana – Viburnum edule: Mitella nuda (212) subassociation. Since the units of each of these two pairs were adjacent to each other on regional soil moisture or soil nutrient gradients, the floristic similarity of these units appears to be related to edaphic affinities.17RESULTS AND DISCUSSIONThe Vegetation ClassificationMid-seral Black Spruce EcosystemsTable 4. Matrix of floristic similarities for vegetation units delineated in mid-seral black spruce ecosystems.   Higher values indicate a greater number of shared species and greater floristic similarity. Codes for vegetation units as in Table 1.Floristic affinities between the vegetation units were also illustrated by the spectra presenting the life form profile for each unit (Figure 2). Except for the provisional Picea mariana – Betula nana (310) association, all other units have similar profiles, with coniferous trees (black spruce, white spruce, and lodgepole pine) and mosses (predominantly Hylocomium splendens, Pleurozium schreberi, and Ptilium crista-castrensis) representing over 60% of each spectrum. While the proportion of coniferous trees and mosses was relatively consistent, the relative frequency of broad-leaved trees, evergreen shrubs, deciduous shrubs, ferns and allies, graminoids, herbs, lichens, and dwarf woody plants varied from unit to unit.Broad-leaved deciduous trees (predominantly aspen) had the highest relative frequency (5 to 10%) in the nutrient-richer communities of the Picea glauca & mariana – Viburnum edule (210) association. Although their proportion was small (about 5%), evergreen shrubs (predominantly Ledum groenlandicum) were characteristic of nutrient-poor communities included in the Picea mariana – Vaccinium vitis-idaea (120) and the Picea mariana – Equisetum sylvaticum (130) associations. As expected, a small proportion (about 5%) of ferns and allies (mainly Equisetum spp.) was present in the spectra of the Picea mariana – Equisetum sylvaticum (130) and the Picea glauca & mariana – Equisetum pratense (220) associations. Although each vegetation unit featured herbs, they had a higher relative frequency (5 to 20%) in the nutrient-richer units: the Picea glauca & mariana – Viburnum edule (210) and Picea glauca & mariana – Equisetum pratense (220) associations. a. Sørenson’s (coincidence) coefficient of floristic similarity based on species presence/absence.Vegetation units110 120 131 132 211 212 220 310Vegetation units110 1.000120 0.514 1.000131 0.461 0.685 1.000132 0.395 0.574 0.686 1.000211 0.385 0.636 0.630 0.558 1.000212 0.349 0.619 0.686 0.623 0.679 1.000220 0.295 0.436 0.510 0.568 0.468 0.491 1.000310 0.114 0.083 0.083 0.113 0.081 0.119 0.119 1.000b. Cover index (Sørenson modified) of floristic similarity based on cover values.Vegetation units110 120 131 132 211 212 220 310Vegetation units110 1.000120 0.245 1.000131 0.176 0.741 1.000132 0.301 0.487 0.483 1.000211 0.363 0.492 0.377 0.543 1.000212 0.182 0.686 0.687 0.467 0.500 1.000220 0.381 0.162 0.148 0.321 0.296 0.157 1.000310 0.040 0.008 0.013 0.045 0.020 0.011 0.049 1.00018RESULTS AND DISCUSSIONThe Vegetation ClassificationScientica Silvica Extension Series, Number 26, 2000Lichens were most abundant in water-deficient communities of the Picea mariana – Cladina stellaris (110) association. Dwarf woody plants (such as Linnaea borealis, Vaccinium scoparium, and V. vitis-idaea) occurred with a low relative frequency (generally <10%) and were most characteristic of nutrient-poor communities of the Picea mariana – Vaccinium vitis-idaea (100) alliance. Figure 2. Life form spectra for the eight basic vegetation units delineated in mid-seral black spruce ecosystems by this study. Codes for vegetation units as in Table 1.0% 25% 75%50% 100%110120131132211212220310Relative frequencyLife form groups:Vegetation unitsConiferous treesBroad-leaved treesEvergreen shrubsDeciduous shrubsFernsGraminoidsHerbsMossesLiverwortsLichensDwarf woody plants19RESULTS AND DISCUSSIONDescription of Plant AssociationsMid-seral Black Spruce EcosystemsDescription of Plant AssociationsThis section expands on the vegetation classification by emphasizing floristic and stand characteristics of the plant associations. As much of this information is presented in diagnostic, summary and plot vegetation tables, the description is brief and focused on the most salient features. We describe and illustrate each of the six plant associations, including their subassociations (if any). The associations are organized according to the order given in Table 1. We emphasize the habitat and vegetation-environment relationships in the next section on site classification.110 Picea mariana – Cladina stellaris plant association(References: Ta ble s 2  and 3; Figures 2 and 3; Appendices 2 and 3)This association represents low-productivity black spruce and lodgepole pine dominated communities that have developed on water-deficient, nutrient-poor sites throughout the BWBS zone and the northern portion of the SBS zone. Conifers, mosses, lichens, and dwarf woody plants are most prominent in the life form spectrum (Figure 2). The forest canopy is typically open, often discontinuous, enabling the growth of shade-intolerant species, such as Arctostaphylos uva-ursi and several lichen species in the understory (Tables 2 and 3). The cover of the other life forms decreases in order from the mosses to the shrubs to the herbs. The constant dominant species in the understory are: Cladina stellaris (also the most important diagnostic species) and Vaccinium vitis-idaea. Although sometimes occurring with high cover, Hylocomium spendens and Pleurozium schreberi may be occasionally absent. The complete absence of Ptilium crista-castrensis suggests that it is intolerant of water deficits and exposure. A greater number of samples would improve characterization of these lichen communities; however these communities are uncommon and, especially on the driest sites, slow to develop, making it difficult to avoid sampling earlier seral stages without black spruce. Figure 3. An open-canopy, old-growth lodgepole pine community (in the foreground) and a mid-seral black spruce community (in the background) representing the Picea mariana – Cladina stellaris (110) association on a moderately dry, nutrient-poor site located on a water-shedding crest in the BWBSdk subzone.20RESULTS AND DISCUSSIONDescription of Plant AssociationsScientica Silvica Extension Series, Number 26, 2000120 Picea mariana – Vaccinium vitis-idaea plant association(References: Ta ble s 2  and 3; Figures 2 and 4; Appendices 2 and 4)This association represents low- to- medium productivity black spruce communities with or without lodgepole pine as a dominant species in the tree layer. These communities occur on slightly water-deficient, nutrient-poor sites throughout the BWBS zone and the northern portion of the SBS zone. Conifers and mosses are the predominant life forms, with a minor proportion (<5%) of lichens, dwarf woody plants, evergreen shrubs, deciduous shrubs, and herbs. Shade-tolerant boreal mosses (Hylocomium splendens, Pleurozium schreberii and Ptilium crista-castrensis) dominate the understory. Forest canopies range from open to closed, and this variation appears to influence the presence and abundance of shade-intolerant species, such as lichens, in the forest understory.Trees are distributed randomly or in clusters. Clusters are typical in pure black spruce stands because of the ability of the species to regenerate by layering. In comparison to the Picea mariana – Cladina stellaris (110) association, the presence of lichens was lower, although small patches of Cladina stellaris and Cladina mitis may occur among mosses. Usually, lichens form patches around or on stones, roots, or poorly decomposed wood. The presence of ericaceous shrubs (e.g., Ledum groelandicum), some herbs, (e.g., Petasites frigidus), and mosses (e.g., Hylocomium splendens and Ptilium crista-castrensis) was higher (Tables 2 and 3). Within the Picea mariana – Vaccinium vitis-idaea (100) alliance, this association is virtually without a diagnostic combination of species (except for Orthilia secunda as an important companion), i.e., it is differentiated by the absence of the species that are characteristic for the other associations of the alliance. Such poor differentiation is characteristic of the communities associated with intermediate (zonal) sites. Figure 4. A semi-open canopy stand of black and white spruce in the understory reinitiation developmental stage. This stand represents the Picea mariana – Vaccinium vitis-idaea (120) association on a slightly dry, nutrient-poor mid-slope site in the BWBSdk subzone. Note the occasional clumps of trees, advance regeneration of black spruce and subalpine fir, and the lower cover of understory vegetation in patches with higher canopy closure.21RESULTS AND DISCUSSIONDescription of Plant AssociationsMid-seral Black Spruce EcosystemsTo determine the magnitude of floristic differences that could be attributed to the influence of regional climate, we stratified the 25 plots of the Picea mariana – Vaccinium vitis-idaea (120) association according to subzones into 4 groups (BWBSdk, BWBSmw, BWBSwk, and combined SBS subzones). This comparison showed the presence of weak differences among the subzones (Table 5). Cladina stellaris and Geocaulon lividum appear to be more frequent in the driest climate (BWBSdk subzone) and Menziesia ferruginea and Vaccinium mebranaceum in the wettest climate (BWBSwk subzone), while no significance was attributed to a higher presence of Equisetum arvense in the BWBSmw subzone. The predominantly drier combined SBS subzones were well differentiated from the BWBS subzones by a number of species; however, few of them signify climatic differences (e.g., Spiraea betulifolia indicating a warmer (milder) climate, and Lonicera involucrata and Petasites frigidus indicating a summer-wet climate).Our findings are in rough concordance with Meidinger and Pojar (1991) who considered Shepherdia canadensis and Geocaulon lividum to be characteristic of the BWBSdk subzone, Lathyrus ochroleucus, Mertensia paniculata, Galium boreale, and Mitella nuda of the BWBSmw subzone, and Abies lasiocarpa and Vaccinium membranaceum of the BWBSwk subzone. The species underlined above were not differential, as they occurred either across several vegetation units, or were diagnostic of the units represented by the Picea glauca & mariana – Viburnum edule (200) alliance, i.e., communities occurring on medium and richer sites. Nevertheless, this comparison suggests that according to the zonal concept, the Picea mariana – Vaccinium vitis-idaea (120) association could be further differentiated into several subassociations, each signifying differences in regional climate. However, we suggest that such a differentiation is inconsequential to our classification for the BWBS zone, particularly in view of (i) the small number of plots, (ii) the classification of mid-seral ecosystems, and (iii) the designation of slightly dry and nutrient poor sites as zonal sites. Even if the differentiation were implemented, it would not change the edaphic characteristics of the resulting subassociations, and hence their vegetation and productivity potentials. Table 5. Potential diagnostic combinations of species for groups of plots of the Picea mariana - Vaccinium vitis-idaea (120) association stratified according to biogeoclimatic units. The diagnostic combination of species for each vegetation unit is shaded in gray..  1, 2, 3  Diagnostic values and species presence and significance classes as defined in Table 2.Biogeoclimatic subzoneBWBS dkBWBS mwBWBS wkall SBSNumber of plots 8 5 5 7SpeciesDiagnostic1 valueSpecies presence2 and significance3BWBdk plotsCladina stellaris  (d)1IV243II 4 II 6 II hGeocaulon lividum (d) V 4 I 1 III hBWBSmw plotsEquisetum arvense (d) I h III + I 1 I hBWBSwk plotsAbies lasiocarpa (ic) II 5 IV 5 III 4Menziesia ferruginea (d) III 5Vaccinium membranaceum (ic) I h III 6 II 2Northern SBS subzonesAster sibiricus (d) III +Goodyera oblongifolia (d) I h III hLinnaea borealis (d) III + II 2 II 1 V 1Lonicera involucrata (d) I + IV +Nephroma arcticum (d) III +Peltigera malacea (d) III +Petasites frigidus (d) II h III 2 II 1 V 2Rosa acicularis (d) II 1 II 2 I 1 IV 2Rubus pubescens (d) III +Spiraea betulifolia (d) III 222RESULTS AND DISCUSSIONDescription of Plant AssociationsScientica Silvica Extension Series, Number 26, 2000130 Picea mariana – Equisetum sylvaticum plant association(References: Ta ble s 2  and 3; Figures 2, 5 and 6; Appendices 2, 5, and 6)This association represents low- to medium-productivity black spruce communities on nutrient-poor sites, usually with lodgepole pine as a minor species. Two subassociations were delineated: (i) 131 typic, which represents communities on fresh, moist, and very moist sites, and (ii) 132 Larix laricina, which represents communities on wet sites, with both occurring throughout the BWBS zone and the northern portion of the SBS zone. Location on flat terrain or in depressions combined with constrained drainage causes the water table to fluctuate during the growing season; i.e., soil moisture conditions may vary from water surplus after snowmelt and spring thaw to water deficit in late spring to water surplus following major summer precipitation events. In addition, a frozen layer, which often persists into the growing season, may be present in very moist and wet soils. Similar to the drier Picea mariana – Vaccinium vitis-idaea (120) association, conifers and mosses are the predominant life forms in this association, with a minor proportion (<5%) of evergreen shrubs, deciduous shrubs, herbs, and dwarf woody plants (Figure 2). The cover of the tree layer varies from 20 to 90%; however, most of the stands have open canopies, which allows better development of the shrub, herb, and moss layers. Equisetum sylvaticum is the only moderately strong differential species for the association, with its presence and cover increasing with increasing water surplus from the typic to the Larix laricina subassociation. A similar trend was observed for Aulacomnium palustre, the most characteristic species for the Larix laricina subassociation and a good indicator of a fluctuating water table. According to the cover-based Sørenson index, the typic (131) subassociation is floristically more similar to the intermediate Picea mariana – Vaccinium vitis-idaea (120) association than to the Larix laricina (132) subassociation (Table 4).  Figure 5. A nearly fully stocked, clumpy, pure black spruce stand representing the Picea mariana – Equisetum sylvaticum: typic (131) subassociation on a very moist, nutrient-poor site with a fluctuating water table in the BWBSdk subzone. Note the high cover of Equisetum sylvaticum in canopy gaps.23RESULTS AND DISCUSSIONDescription of Plant AssociationsMid-seral Black Spruce Ecosystems Figure 6. An open-canopy, clumpy, 109 year-old (@ bh) stand of pure black spruce representing the Picea mariana – Equisetum sylvaticum: Larix laricina (132) subassociation on a wet, nutrient-poor site in the BWBSdk subzone sample (plot 71).  24RESULTS AND DISCUSSIONDescription of Plant AssociationsScientica Silvica Extension Series, Number 26, 2000210 Picea glauca & mariana – Viburnum edule plant association(References: Ta ble s 2  and 3; Figures 2, 7 and 8; Appendices 2, 7, and 8)This association represents species-diverse, medium- to high-productivity white and black spruce communities on nutrient-medium and richer sites, usually with lodgepole pine and/or trembling aspen as occasional major or minor species. Two closely related subassociations were delineated: (i) Shepherdia canadensis (211), which represents communities on slightly water-deficient sites, and (ii) Mitella nuda (212), which represents communities on fresh, moist and very moist sites. Both associations occur throughout the BWBS and the northern portion of the SBS zone. As with their moisture-equivalent but nutrient-poorer counterparts (the Picea mariana – Vaccinium vitis-idaea (120) association and the Picea mariana – Equisetum sylvaticum: typic (131) subassociation), the water table will fluctuate during the growing season if these communities are located on flat terrain or in depressions with fine-textured soils and constrained drainage. Soil moisture conditions may change from water surplus after snowmelt and spring thaw to water deficit in late spring, to water surplus following major summer precipitation events.Conifers and mosses are the predominant life forms; however, the proportion of deciduous trees (trembling aspen), deciduous shrubs (e.g., Lonicera involucrata and Viburnum edule) and herbs (e.g., Arnica cordifolia, Aster ciliolatus, and Osmorhiza berteroi) is markedly higher compared to the Picea mariana – Vaccinium vitis-idaea (100) alliance (Tables 2 and 3). The cover of the tree layer is generally high (over 50%), yet allows a moderate development of the herb layer. The Picea glauca & mariana – Viburnum edule (210) association is well differentiated from the wetter Picea glauca & mariana – Equisetum pratense (220) association by species including Epilobium angustifolium, Galium boreale, G. triflorum, and Viburnum edule; however, the Shepherdia canadensis (211) and Mitella nuda (212) subassociations are floristically quite similar (Table 4). Shepherdia canadensis is the most significant diagnostic (and indicator) species for the drier communities, with its presence and cover decreasing with increasing water surplus. Mertensia paniculata and Mitella nuda are considered important diagnostic species for the wetter communities, with their presence increasing with increasing water surplus.25RESULTS AND DISCUSSIONDescription of Plant AssociationsMid-seral Black Spruce Ecosystems Figure 7. A nearly closed-canopy black spruce stand representing the Picea glauca & mariana– Viburnum edule: Shepherdia canadensis (211) subassociation on a slightly dry, nutrient medium, mid-slope site in the BWBSmw subzone. Note the high cover of Petasites frigidus, a species characteristic of the Picea glauca & mariana – Viburnum edule alliance and of a fluctuating water table.  Figure 8. A nearly closed-canopy mixture of black spruce and white spruce representing the Picea mariana – Viburnum edule: Mitella nuda (212) subassociation on a fresh, nutrient-rich, mid-slope site in the BWBSdk subzone. Note the high cover of Arnica cordifolia, a companion species of the Picea glauca & mariana – Viburnum edule alliance.26RESULTS AND DISCUSSIONDescription of Plant AssociationsScientica Silvica Extension Series, Number 26, 2000220 Picea glauca & mariana – Equisetum pratense plant association(References: Ta ble s 2  and 3; Figures 2 and 9; Appendices 2 and 9)This insufficiently sampled (3 plots), and therefore tentative, association represents low-productivity, black and white spruce dominated communities on wet, nutrient-medium and richer sites throughout the BWBS and the northern portion of the SBS zone. Occurrence on gentle slopes may result in good drainage, but occurrence on flat terrain or in depressions combined with constrained drainage results in a fluctuating water table during the growing season; i.e., soil moisture conditions may change from water surplus after snowmelt and spring thaw to water deficit in late spring to water surplus following major summer precipitation events.Conifers and mosses are the predominant life forms, but these communities also feature a higher proportion (>5%) of ferns and allies (Equisetum pratense and E. scirpoides), graminoids (mainly Carex spp.), and herbs than other units (Figure 2). The cover of the tree layer is generally low (about 50%). Compared to other vegetation units, this association is characterized by many differential species, several of which are indicators of easily available soil nitrogen (e.g., Angelica genuflexa, Geum macrophyllum, and Senecio triangularis).  Figure 9. A nearly fully stocked, but clumpy, 99 year-old (@bh) pure black spruce stand representing the Picea glauca & mariana – Equisetum pratense (220) association on a wet, nutrient-medium site on flat terrain in the BWBSdk subzone.27RESULTS AND DISCUSSIONDescription of Plant AssociationsMid-seral Black Spruce Ecosystems310 Picea mariana – Betula nana plant association(References: Ta ble s 2  and 3; Figures 2 and 10; Appendix 2)This insufficiently sampled (1 plot), tentative association represents low-productivity communities on very wet, nutrient-medium and richer sites, usually with both black and white spruce as the leading but scattered tree species. These communities could be considered transitional between forested and non-forested ecosystems throughout the BWBS and the northern portion of the SBS zone. Our single community sampled probably represents medium soil nutrient conditions considering the relatively low cover of ericaceous shrubs and Sphagnum spp. Plant communities on very wet, nutrient-poor sites will be expected to be ombotrophic, non-forested bogs dominated by Ledum groelandicum and Sphagnum spp., with scattered black spruce.  Figure 10. A poorly forested Picea mariana –  Betula nana (310) community north of Smithers.28Scientica Silvica Extension Series, Number 26, 200029RESULTS AND DISCUSSIONThe Site ClassificationMid-seral Black Spruce EcosystemsThe Site ClassificationWe derived 8 site associations from 8 mid-seral vegetation units (plant associations or subassociations), thus there is 1:1 correspondence between vegetation units and site associations (Table 6). This good correspondence between vegetation and habitats was attributed to the small number of vegetation units, each with a nearly exclusive range of soil moisture and nutrient regimes. The edaphic individuality of site associations is illustrated on the edatopic grid (Figure 11) and in the summary environmental table (Table 7). Table 6. Synopsis of site associations delineated in mid-seral black spruce ecosystems by this study, showing their relationships with the parent vegetation units.From a climatic perspective, each site association includes ecosystems from nearly all BWBS variants and the northern subzones/variants of the SBS zone. If climate, as expressed by biogeoclimatic subzones/variants, has a strong influence on vegetation, then this climatic influence should be most strongly expressed on zonal sites. We considered the sites where the Picea mariana – Vaccinium vitis-idaea plant association occurred to be closest to zonal, and stratified the sample plots according to the membership in the subzones studied. As the vegetation analysis showed weak floristic differences between subzones (Table 5), we framed only one ‘zonal’ site association (SbPl – Moss) for the whole study area. Since the floristic differences due to climate within other well-sampled site associations were generally minor, we concluded that it would be unnecessary to undertake additional floristic analysis within each of the site associations. It is more useful to describe apparent trends and divide each site association into site series according to biogeoclimatic subzones/variants. Each set of site series may reflect minor variations in vegetation and soil characteristics and, more importantly, differences in the distribution pattern of ecosystems imposed by regional climates. For example, ecosystems on the driest sites will be expected to be more frequent in the landscape in the driest subzones than in the wettest subzones, and will likely feature a higher and more consistent cover of xerophytic species.One of the premises of plant ecology is that there are predictable, if inexact, relationships between vegetation patterns and environmental gradients. These relationships can be used to infer certain environmental conditions from the presence of a given plant community or, conversely, to predict the presence or development of plant communities given certain environmental conditions. The steepest gradients in forested ecosystems are usually climatic and edaphic (soil moisture, soil nutrients, and aeration). Other, usually indirect, environmental factors that affect plant communities (and can be used to predict their presence) include: aspect, slope gradient, slope position, parent material, soil texture, and soil drainage.Site association Parent vegetation unit100 SbPl – Lichens 110 Picea mariana – Cladina stellaris association200 SbPl – Moss 120 Picea mariana – Vaccinium vitis-idaea association300 Sb – Wood Horsetail 131 Picea mariana – Equisetum sylvaticum: typic subassociation400 Sb – Tamarack 132 Picea mariana – Equisetum sylvaticum: Larix laricina subassociation500 SbSw – Soopolallie 211 Picea glauca & mariana – Viburnum edule: Shepherdia canadensis subassociation 600 SbSw – Common Mitrewort 212 Picea glauca & mariana – Viburnum edule: Mitella nuda subassociation 700 SbSw – Meadow Horsetail 220 Picea glauca & mariana – Equisetum pratense plant association800 (Sb) – Swamp Birch 310 Picea mariana – Betula nana plant association30RESULTS AND DISCUSSIONThe Site ClassificationScientica Silvica Extension Series, Number 26, 2000Table 7. Summary environmental table for the site associations in mid-seral black spruce ecosystems delineated in this study. Continuous properties are characterized by mean and range; categorical properties are described by the percentage of the sample plots in each class.Site associationProperty 100SbPl - Lichens200SbPl - Moss300Sb - Wood Horsetail400Sb - Tamarack500SbSw - Soopolallie600SbSw - Common Mitrewort700SbSw - Meadow Horsetail800Sb - Swamp BirchNumber of plots 5 25 34 13 13 28 3 1Subzone1BWBSdk - 80BWBSmw - 20BWBSdk - 48BWBSmw - 20BWBSwk - 20SBSdk - 4SBSdw - 8 BWBSdk - 26BWBSmw- 65BWBSwk - 3SBSmk - 6BWBSdk - 8BWBSmw- 84BWBSwk - 8BWBSdk - 23BWBSmw - 8SBSmk - 31SBSdw - 38BWBSdk - 19BWBSmw - 67SBSdk - 4SBSdw - 4 SBSmk - 6BWBSmw - 33BWBSwk - 33SBSdw - 34BWBSdw - 100Soil moisture regime2 2/MD - 803/SD - 203/SD - 284/SD - 685/F&M - 4 5/F&M - 506/VM - 506/VM - 87/W - 923/SD - 104/SD - 90 5/F&M - 716/VM - 297/W - 100 8/VW- 100 Soil nutrient regime3 VP - 60P - 40VP - 16P - 80 M - 4VP - 38P - 56 M - 6 VP - 62P - 38 P - 15M - 46R - 38P - 4M - 68R - 18VR - 11M - 67R - 33M - 100 Elevation (m) 918 (840 - 1020) 933 (400 - 1190) 841 (350 - 1170) 646 (350 - 1160) 792 (390 - 955) 801 (340 - 1030) 950 (840 - 1020) 880Slope gradient (%) 16 (2 - 40) 21 (0 - 82) 11 (0 - 36) 2 (0 - 16) 9 (0 - 32) 7 (0 - 31) 0 0Slope aspect4 N - 40E - 20S - 40N - 28E - 16S - 28W - 8F - 20N - 15E - 9S - 18W - 29F - 29W - 23F - 77N - 23E - 15S - 23W - 8F - 31N - 25E - 4S - 14W - 18F - 39F - 100 F - 10031RESULTS AND DISCUSSIONThe Site ClassificationMid-seral Black Spruce EcosystemsForest floor thickness (cm) 7 (5 - 10) 11 (4 - 30) 13 (8 - 23) 18 (12 - 30) 11 (2 - 40) 13 (9 - 23) 15 (9 - 24) 25Generalized textural class5L - 80S - 20L - 72S - 24O - 4C - 6L - 44S - 6O - 38C - 8L - 23O - 69C - 8L - 70S - 22C - 22L - 61S - 4O- 14O - 100 C - 100Potential rooting depth (cm) 53 (25 - 60) 50 (10 - 80) 49 (15 - 90) 49 (30 - 70) 52 (15 - 70) 48 (20 - 100) 53 (40 - 70) 70Water table depth (cm)N/A6N/A or > 70 N/A or 15 - 70 5 - 50 N/A or > 70 N/A or 10 - 75 30 - 35 10Soil drainage7R - 40W - 40M - 20R - 16W - 36M - 32I - 16W - 6M - 12I - 29P - 53P - 54V - 46R - 8W - 31M - 54I - 8W - 7M - 7I - 68P - 18 P - 33V - 67V - 100Stand age (years@ bh)796 (54 - 151) 98 (37 - 176) 102 (48 - 185) 107 (69 - 151) 90 (44 - 108) 95 (54 - 157) 158 (144 - 172) 77Site index (m @50yrs bh age)89.0(7.3 - 9.9) 9.7(7.3 - 13.3) 8.6(4.7 - 11.5) 9.6(6.9 - 11.6) 12.1(10.4 - 13.9) 11.2(7.8 - 14.0) 6.3 9.2Tree layer cover (%) 41 (20 - 70) 50 (15 - 90) 54 (20 - 96) 47 (22 - 86) 69 (45 - 90) 63 (30 - 90) 53 (50 - 60) 10Shrub layer cover (%) 14 (1 - 48) 16 (0 - 66) 16 (0 - 44) 30 (0 - 80) 12 (0 - 51) 13 (0 - 68) 13 (6 - 23) 46Herb layer cover (%) 1 (0 - 2) 3 (0 - 13) 7 (0 - 33) 7 (1 - 17) 10 (0 - 24) 11.4 (0 - 55) 26 (5- 62) 25Moss layer cover (%) 68 (38 - 97) 88 (45 - 100) 90 (52 - 100) 82 (32 - 100) 61 (1 - 97) 76 (0 - 100) 68 (40 - 93) 461 Subzones of the Boreal Black and White Spruce Zone: BWBSdk - Dry Cool BWBS, BWBSmw - Moist Warm BWBS, BWBSwk - Wet Cool BWBW; and the Sub-Boreal Spruce Zone: SBSdk - Dry Cool SBS, SBSdw - Dry Warm SBS, SBSmk - Moist Cool SBS.2 Relative/actual moisture regime: 2/MD-subxeric/moderately dry, 3/SD-submesic/slightly dry, 4/SD-mesic/slightly dry, 5/F&M-subhygric/fresh and moist, 6/VM-hygric/very moist, 7/W-subhydric/wet, 8/VW-hydric/very wet, f - fluctuating water table3 VP-very poor, P-poor, M-medium, R-rich, VR-very rich4 N-north, E-east, S-south, W-west, F-flat5 S-sandy, L-loamy, C-clayey, O-organic (See Ta ble  8 for definitions)6 N/A - not applicable; N/D - not determined7 R-rapid, W-well, M- moderately well, I-imperfect, P-poor, V-very poor8 Site Index and stand age data are missing for some plots. See Appendices 10 - 16 for details.Site associationProperty 100SbPl - Lichens200SbPl - Moss300Sb - Wood Horsetail400Sb - Tamarack500SbSw - Soopolallie600SbSw - Common Mitrewort700SbSw - Meadow Horsetail800Sb - Swamp BirchNumber of plots 5 25 34 13 13 28 3 132RESULTS AND DISCUSSIONThe Site ClassificationScientica Silvica Extension Series, Number 26, 2000In this study, the variation along regional soil moisture and nutrient gradients was sufficient for the exclusive differentiation of site associations. Thus, regardless of the vegetation present on the site (or the stage in stand development), any site within the studied edaphic range can be identified, i.e., assigned to one of the 8 site associations based on an estimate of soil moisture and nutrient conditions of the site (Figure 11). The edaphic limits of some site associations have been extended to include the soil moisture and nutrient conditions where we expect similar plant communities to develop.There are two sets of site associations: the nutrient poorer ones (100 - 400) with SNRs ranging from very poor to poor, and the nutrient-richer ones (500 - 600), with SNRs ranging from medium to rich (occasionally very rich). The difference in SNRs between these two sets is supported by soil chemical analysis (Kayahara et al. 2000, submitted manuscript) and by a distinctly higher (15-27%) relative frequency of nitrogen-rich plant indicators in the soil nutrient spectra of the SbSw – Soopolallie, SbSw – Common Mitrewort, and SbSw – Meadow Horsetail site associations (Figure 12). A relative frequency of nitrogen-rich indicators exceeding 9% was considered to be diagnostic for medium and richer SNRs (Wang, 1992). However, the field-identified SNRs showed some overlap between these two sets of site associations (Table 7). This is due to the fact that the assessment of soil nutrient regime using soil properties reflects the nutrient status throughout the soil profile, while indicator plant analysis primarily reflects the nutrient status of the forest floor. Figure 11. Edatopic grid showing the generalized relationships of the eight site associations to soil moisture and soil nutrient regimes. Numerical codes for site associations as in Table 6.VP12345678VDMDSD(f)F -M(f)VM(f)W(f)VW(f)PMRVRSoil nutrient regimeSoil moisture regime100SbPl-Lichens200SbPl-Moss500SbSw-Soopolallie300Sb-Wood Horsetail600SbSw-CommonMitrewort 400Sb-Tamarack700SbSw-Meadow Horsetail800 (Sb)-Swamp birchfens, marshes, and swampsgrasslands, shrubs,and/or stunted treesnon-forested bogs33RESULTS AND DISCUSSIONThe Site ClassificationMid-seral Black Spruce EcosystemsFigure 12. Soil nutrient spectra for the eight site associations showing the frequency of plants indicating various soil nutrient conditions relative to all soil nutrient indicator species. Numerical codes for site associations are listed in Table 6. Mid-points of rich indicators from Wang (1992).Figure 13. Soil moisture spectra for the eight site associations showing the frequency of plants indicating various soil moisture conditions relative to all soil moisture indicator species. Numerical codes for site associations are listed in Table 6.100200300400500600700800Site association0% 25% 75%50% 100%Relative frequency of soil nutrient indicator speciesSoil nutrient regime midpoints basedon the percentage of the rich indicator species group  poor medium richIndicator species groups for soil nutrients: VP1%P4%M9%R25%VR38%Site association1002003004005006007008000% 25% 75%50% 100%Relative frequency of soil moisture indicator speciesIndicator species groups for soil moisture:Excessively to very dryVery to moderately dryModerately dry to freshFresh to very moistVery moist to wetWet to very wet34RESULTS AND DISCUSSIONThe Site ClassificationScientica Silvica Extension Series, Number 26, 2000Similarly, the indicator plant analysis supported differentiation of site associations into 5 sets of soil moisture conditions: (1) very dry to moderately dry (2) slightly dry, (3) fresh to very moist, (4) wet, and (5) very wet (Figure 13). However, we did not sample the very dry, nutrient-medium and richer sites, which support grasslands and low-vigour trembling aspen ecosystems (Banner et al. 1993), or, except for the one plot in the 800 (Sb) – Swamp birch site association, the very wet sites, which support poorly forested and non-forested bogs, fens, marshes, and swamps (DeLong et al. 1990; MacKinnon et al. 1990; Banner et al. 1993). In order from very dry to wet sites, the soil moisture spectra showed a consistent decrease in the relative frequency of the indicators species groups of moisture-deficient soils, and a consistent increase in the relative frequency of the indicator groups of water-surplus soils in both the nutrient-poorer and nutrient-richer sites. These trends suggests that the separation of site associations according to these soil moisture sets reflects a natural pattern in black spruce ecosystems because the differences in edaphic conditions between site associations are well reflected by the floristic composition of understory vegetation. We propose that for this study area a distinction should be made between two sets of soil moisture conditions: (i) with a groundwater table which exhibits no or relatively minor fluctuations (typically associated with no or minor soil drainage constraints), and (ii) with a strongly fluctuating water table (typically associated with imperfectly and poorly drained soils). While the ‘standard’ (from very dry to very wet) SMRs are to used with first set, the adjective fluctuating (f) should be used with the second set to indicate significant changes in soil moisture during the growing season. A strongly fluctuating water table can be expected to occur on flat terrain or in depressions when the associated soils are fine-textured, poorly structured, have a low content of coarse fragments, have a compacted, root-restricting layer close to the ground surface, and feature a gleyed (occasionally) soil layer/horizon. Under such conditions, soil moisture conditions may change from water surplus after snowmelt and spring thaw to water deficit in late spring and again to water surplus following major summer precipitation events. For example, the slightly dry fluctuating SMR may be characterized by growing-season soil moisture conditions ranging from very moist to slightly dry, with slightly dry conditions being most frequent during the growing season.When describing site associations, we proposed potential site types using one or two edaphic adjectives indicative of aberrant properties in relation to the majority of the sample plots in a particular site association (the typic site type) (Table 8). We do not expect floristic difference between site types; however, if they occur, they probably reflect edaphic differences. For example a shallow site type will be expected to be drier compared to moderately deep and deep sites; a gleyed site type will be expected to be associated with a strongly fluctuating water table, and a slope-skeletal site type will be expected to be associated with unconstrained soil drainage.  35RESULTS AND DISCUSSIONThe Site ClassificationMid-seral Black Spruce EcosystemsTable 8.  Definitions of the diagnostic edaphic properties used to frame site types in the site classification of mid-seral black spruce ecosystems.  These properties can represent the central concept (i.e. typic) of a site type, or when used as an adjective on the site association name, it can describe the aberrant properties of a site type. Adjective DefinitionType and degree of expression of soil horizons GleyedA soil that has a horizon(s) formed under poor drainage (wet and partly anaerobic) conditions which results in the reduction of iron and other elements and in gray colours and/or mottles; the soil belongs to the gleyed subgroups of Brunisols, Luvisols, Podzols, or Regosols.GleysolicA soil that belongs to the Gleysolic order (Orthic or Humic Gleysols).OrganicA soil that belongs to the Organic order (Folisols, Fibrisols, Mesisols, or Humisols).Particle sizeSandyTexture of the fine earth is sand or loamy sand, but not loamy very fine sand or very fine sand; coarse fragments make up <35% by volume. LoamyTexture of the fine earth is loamy very fine sand, very fine sand, or finer, but the amount of clay is <35%; coarse fragments are <35% by volume. ClayeyFine earth contains ≥35% clay by weight, and coarse fragments are <35% by volume. SkeletalCoarse fragments make up ≥35% by volume with enough fine earth to fill interstices larger than 1 mm; this adjective is used together with the particle size classes defined above (sandy, loamy, and clayey). Rooting depthShallowA soil that has a rooting depth of <30 cm. Moderately deepA soil that has a rooting depth of ≥30 cm but <100 cm. DeepA soil that has a rooting depth of ≥100 cm. Landform characteristicsSlopeA site that has a slope gradient of ≥35% but <80%.Steep-slopeA site that has a slope gradient of ≥80%.36RESULTS AND DISCUSSIONDescription of Site AssociationsScientica Silvica Extension Series, Number 26, 2000Description of Site AssociationsThis section expands on the site classification by emphasizing the important environmental (habitat) features of each site association. As much of this information is presented in summary and plot environmental tables (Table 7, Appendices 10 to 16), the descriptions are brief and focus on the most salient features. We describe each of the eight site associations delineated in this study and give potential site types (according to the major edaphic differences between sample plots within a site association). Site associations are organized in the same order as in Table 6. Considering the large number of site series and site types, the number of sample plots in this study was not sufficient to conduct a meaningful analysis of the vegetation-environment data for each of these categories. Ideally, each site association should also be characterized by a generalized chronosequence of all vegetation units that may develop on the sites in the process of secondary succession; however, this also could not be done in the present study.The potential site series derived from the delinated site associations can be easily framed by prefixing the biogeoclimatic unit (subzone or variant) symbol to the name of the site association. For example, the site series which can be derived from the SbPl – Lichens  site association are (1) BWBSdk1/SbPl – Lichens, (2) BWBSdk2/SbPl – Lichens, (3) BWBSmw1/SbPl – Lichens, (4) BWBSmw2/SbPl – Lichens, (5) BWBSwk1/SbPl – Lichens, and (6) BWBSwk2/SbPl – Lichens.37RESULTS AND DISCUSSIONDescription of Site AssociationsMid-seral Black Spruce Ecosystems100 SbPl – Lichens site association(References: Ta ble s 6  and 7; Figures 11, 12, 13, and 14; Appendix 10)Submontane to montane, very dry and moderately dry, nutrient-very poor and poor, well-aerated soils on water shedding sitesThe SbPl – Lichens site association was derived from the Picea mariana – Cladina stellaris (110) plant association, which is most common in drier BWBS subzones (Table 7). The central edaphic concept (typic site type) is represented by moderately deep, coarse-skeletal Humo-Ferric Podzols that have formed on crests, mid-slopes, and flat terrain. The associated humus forms are thin Mors, predominantly Hemimors. The potential aberrant site types are shallow and slope (Appendix 10).The SbPl – Lichen site association represents a complex of azonal sites with low-productivity that are marginally suitable for timber production, with a site index (50 yrs @ bh) for black spruce of <9 m. A growing-season water deficit and severe nitrogen deficiency are the fundamental growth constraints. Spectral analysis showed that the soil moisture spectrum is dominated by the indicators of very dry and moderately dry SMRs (Figure 13), and the soil nutrient spectrum is dominated almost entirely by the indicators of very low availability of soil nitrogen (Figure 12). Wind strongly influences the vegetation on crests and upper slopes: it removes organic particles, affects crown development and is the cause of frequent windthrow. Fire disturbance may result in the establishment of predominantly lodgepole pine stands or mixtures of lodgepole pine and black spruce, depending on the composition of the original stands. Depending on the history of fire, regeneration, and windthrow, these azonal sites may lack a continuous vegetation cover, and they often contain patches of exposed mineral soil. Since the canopy is generally open, lodgepole pine may regenerate in larger gaps and form a significant component in late-seral stages (Figure 14). Figure 14. An open-canopy, clumpy mosaic of old-growth lodgepole pine cohorts on a SbPl – Lichen site. The soil parent materials of this site are sand dune deposits. Note the high cover of lichens in the open and the regeneration of lodgepole pine and black spruce close to the clumps.38RESULTS AND DISCUSSIONDescription of Site AssociationsScientica Silvica Extension Series, Number 26, 2000200 SbPl – Moss site association(References: Ta bl es  6 and 7; Figures 11, 12, 13, and 15; Appendix 11)Submontane to montane, slightly dry (infrequently with a fluctuating water table), nutrient-very poor and -poor, well to adequately aerated soils on more or less zonal sitesThe SbPl – Moss site association was derived from the Picea mariana – Vaccinium vitis-idaea (120) plant association, which is considered to represent zonal sites throughout the BWBS zone (Table 6). Compared to other sites, these moss sites are floristically indistinct and best characterized in advanced stages of stand development by a high and continuous cover of mosses, mostly Pleurozium schreberi, Hylocomium splendens, and Ptilium crista-castrensis. The central edaphic concept (typic site type) is represented by moderately deep, loamy-skeletal Brunisols, Luvisols or Humo-Ferric Podzols that have developed on a variety of terrain. The associated humus forms are Mors, predominantly Hemimors or Rhizomors. The potential aberrant site types are shallow, slope, steep-slope, gleyed, and organic (Appendix 11).The SbPl – Moss site association represents a complex of low- to medium-productivity sites, with a black spruce site index (50 yrs @ bh) ranging from 9 to 13 m. However, the black spruce site index was <9 m on organic and gleyed soils and high-elevation (>1,100 m) sites. Cool soils and soil nitrogen deficiency are thought to be the principal growth constraints. The soil moisture spectrum of this site association features about the same proportion of all soil moisture indicator groups (except of the very moist to wet group) (Figure 13). The presence of the wet to very wet indicator species group on these upland sites is misleading as it reflects the presence of Ledum groelandicum. This species is used in cool temperate and mesothermal climates as the indicator of waterlogged sites, but is commonly found on drier upland sites in boreal climates. The indicators of a very low soil nitrogen availability dominate the soil nutrient spectrum almost entirely (Figure 12).  Figure 15. The development and persistence of high density stands is typical for black spruce, particularly on intermediate sites, such as those represented by the SbPl – Moss or SbSw – Soopolallie site associations.39RESULTS AND DISCUSSIONDescription of Site AssociationsMid-seral Black Spruce Ecosystems300 Sb – Wood Horsetail site association(References: Ta ble s 6  and 7; Figures 11, 12, 13, and 16; Appendix 12)Submontane to montane, fresh, moist, and very moist (frequently with a fluctuating water table and restricted aeration), nutrient-very poor and -poor soils on water-receiving sites.The Sb – Wood Horsetail site association was derived from the Picea mariana – Equisetum sylvaticum: typic (131) plant subassociation, which is distributed predominantly on lower slopes throughout the BWBS zone. The central edaphic concept (typic site type) is represented by moderately deep, loamy-skeletal Brunisols, Luvisols, or Humo-Ferric Podzols, without a growing-season water deficit or with the water table >60 cm deep. The associated humus forms are Mors, predominantly Hemimors. The potential aberrant site types are slope, gleyed, gleysolic, and organic, with the latter two typically associated with flat terrain and depressions (Appendix 12).The SbPl – Wood Horsetail site association represents a complex of low- to medium-productivity sites, with the black spruce site index (50 yrs @ bh) typically ranging from 8 to 10 m. The site index decreases with increasing elevation and decreasing depth of the water table; values of <8 m are characteristic of very moist organic soils. The very moist to wet and wet to very wet indicator species groups predominate in the soil moisture spectrum, while the presence of water-deficient indicator species groups is indicative of fluctuating soil moisture conditions (Figure 13). As in all other site associations on nutrient poor sites, the indicators of a low availability of soil nitrogen dominate the soil nutrient spectrum almost entirely (Figure 12). Cool soils, often with a frozen layer that persists into the growing season in the very moist and wet soils, deficient aeration, and nitrogen deficiency are thought to be the principal growth constraints. A long-lasting snow cover, restricted outflow of excess groundwater, and the presence of fine organic materials result in a fluctuating and, if not stagnant, very slowly moving groundwater table. Accumulation of organic materials on these sites progresses at a greater rate than their decomposition, which results in the development of a thick forest floor soon after disturbance.  Figure 16. A dense stand of black spruce in the stem exclusion developmental stage on a very moist, nutrient poor Sb – Wood Horsetail site. Note the random distribution pattern of individual trees that is characteristic of moist and very moist, but not wet sites.40RESULTS AND DISCUSSIONDescription of Site AssociationsScientica Silvica Extension Series, Number 26, 2000400 Sb – Tamarack site association (References: Ta bl es  6 and 7; Figures 11, 12, 13, and 17; Appendix 13)Submontane to montane, wet (infrequently with a fluctuating water table), nutrient-very poor and -poor, and poorly aerated soils on water-collecting sites.The Sb – Tamarack site association was derived from the Picea mariana – Equisetum sylvaticum: Larix laricina (132) plant subassociation, which is distributed throughout the BWBS zone. The central edaphic concept (typic site type) is represented by organic soils (Fibrisols, Mesisols, and Humisols), with the growing-season water table <30 cm deep. The associated humus forms are Mors, predominantly Fibrimor (Table 7). The potential aberrant site type is gleysolic, which may be associated with flat terrain or very gentle slopes (Appendix 13).The Sb – Tamarack site association represents low- to medium-productivity sites, with a black spruce site index (50 yrs @ bh) ranging from 9 to 11 m. Site index decreases with increasing elevation and decreasing aeration. When accounting for ‘low-productivity’ sample plots within the SbPl – Moss and Sb – Wood Horsetail site associations, the growth performance of black spruce on these sites and tamarack sites is approximately within the same range - between 9 and 11 m. This suggests that neither a moderate water deficit nor water surplus have a significant influence on black spruce growth. A long-lasting snow cover and somewhat restricted outflow of excess groundwater result in a very slowly moving groundwater table. Accumulation of organic materials in these sites progresses at a greater rate than their decomposition, which results in the development of a thick forest floor soon after disturbance.The wet to very wet indicator species group predominates in the soil moisture spectrum, while the presence of water-deficient indicator species groups, which is considered to be indicative of fluctuating soil moisture conditions, is minor (Figure 13). As in all other site associations on nutrient poor sites, the indicators of a low availability of soil nitrogen (Figure 12) dominate the soil nutrient spectrum almost entirely.  Figure 17. A dense stand of black spruce in the stem exclusion developmental stage on a wet, nutrient poor Sb – Tamarack site. Note the random group (cluster) tree distribution pattern that is characteristic of wet sites.41RESULTS AND DISCUSSIONDescription of Site AssociationsMid-seral Black Spruce Ecosystems500 SbSw – Soopolallie site association (References: Ta ble s 6  and 7; Figures 11, 12, 13, and 18; Appendix 14)Submontane to montane, slightly dry (infrequently with a fluctuating water table), nutrient-medium and richer, well aerated to adequately aerated soils on water shedding sitesThe SbSw – Soopolallie site association, a nutrient-richer counterpart to the SbPl – Moss site association (Figure 11), was derived from the Picea glauca & mariana – Viburnum edule: Shepherdia canadensis (211) plant subassociation, which was found to be distributed in the BWBS zone and in the SBSdk and SBSdw subzones. Compared to the SbPl – Moss site association, the Soopolallie sites are distinguished by a higher proportion of deciduous trees (Populus tremuloides), deciduous shrubs (e.g., Shepherdia canadensis and Viburnum edule), and herbs. The central edaphic concept (typic site type) is represented by moderately deep, loamy-skeletal Brunisols or Luvisols, which have developed on mid- and lower slopes, and occasionally on flat terrain. The associated humus forms are Mors (Hemimors) or Moders (Mormoders and Leptomoders). The potential aberrant site types are shallow and gleyed (Appendix 14).The SbSw – Soopolallie site association represents generally medium- to high-productivity sites for growth of lodgepole pine, white spruce, black spruce, and trembling aspen, with the black spruce site index (50 yrs @ bh) ranging from 10 to 14 m. Apart from climatic constraints, cool soils are thought to be the principal growth constraint. The soil moisture spectrum of this site association is dominated by the moderately dry to fresh and fresh to very moist indicator species groups; however, the very dry to moderately dry group is also well represented (Figure 13). This combination suggests slightly dry soil moisture conditions. The soil nutrient spectrum shows that the nitrogen-rich indicator species group is well represented (>5% relative frequency) signifying a rich SNR (Figure 12).  Figure 18. A semi-open canopy of a lodgepole pine and black spruce mixture on a SbSw – Soopolallie site in the SBSdw subzone (sample plot 89). Although the black spruce site index (50 yrs @ bh) of 11.2 m is unimpressive, note that at the breast height age of about 85 years, black spruce trees have developed into the upper canopy.42RESULTS AND DISCUSSIONDescription of Site AssociationsScientica Silvica Extension Series, Number 26, 2000600 SbSw – Common Mitrewort site association (References: Ta bl es  6 and 7; Figures 11, 12, 13, 19 and 20; Appendix 15)Submontane to montane, fresh, moist, and very moist (frequently with a fluctuating water table and restricted aeration), nutrient-medium and richer soils on water-receiving sites.The SbSw – Common Mitrewort site association, a nutrient-richer counterpart to the Sb – Wood Horsetail site association, was derived from the Picea glauca & mariana – Viburnum edule: Mitella nuda (212) plant subassociation. It is found predominantly in the BWBSmw subzone, but is not limited to this subzone. The central edaphic concept (typic site type) is represented by moderately deep, fine loamy-skeletal, gleyed Brunisols or Luvisols that have developed on gentle (<5%) lower slopes or on flat terrain. The associated humus forms are Mors (Hemimors and Rhizomors) or Moders (Mormoders). The potential aberrant site types are clayey (sandy clay, clay, silty clay), gleysolic, and organic (Appendix 15).Compared to the Sb – Wood Horsetail site association, these common mitrewort sites are distinguished by a higher proportion of deciduous trees (Populus trichocarpa and P. tremuloides), deciduous shrubs (e.g., Lonicera involucrata and Viburnum edule), and herbs (e.g., Epilobium angustifolium, Mertensia paniculata, and Mitella nuda). The soil moisture spectrum of this site association is dominated by the moderately dry to fresh and fresh to very moist indicator species groups; however, the very moist to wet and wet to very wet groups are also well represented (Figure 13). The soil nutrient spectrum shows that the nitrogen-rich indicator species group is represented with a mean relative frequency of >9%, which signifies a medium SNR (Figure 12). The SbSw – Common Mitrewort site association represents generally medium- to high-productivity sites for the growth of lodgepole pine, white spruce, black spruce, balsam poplar, and trembling aspen. The black spruce site index (50 yrs @ bh) ranges from 8 to nearly 14 m. Apart from climatic constraints, cool soils are thought to be the principal growth constraint. Site index decreases with increasing elevation and decreasing depth of the water table; the values <9 m are characteristic of very moist organic soils.43RESULTS AND DISCUSSIONDescription of Site AssociationsMid-seral Black Spruce Ecosystems Figure 19. A fully stocked, 78 year-old (@ bh) black spruce stand in the early understory reinitiation developmental stage on a moist, nutrient medium SbSw – Common mitrewort site in the BWBSmw subzone (sample plot 111). Note the larger cover of deciduous shrubs and herbs underneath a less dense canopy.Figure 20. A canopy profile of a 70 year-old (@ bh) black spruce stand in the early understory reinitiation developmental stage on a moist, nutrient medium SbSw – Common mitrewort site in the SBSdk subzone. Note the development of club-like crown tops. 44RESULTS AND DISCUSSIONDescription of Site AssociationsScientica Silvica Extension Series, Number 26, 2000700 SbSw – Meadow Horsetail site association (References: Ta bl es  6 and 7; Figures 11, 12, 13 and 21; Appendix 16)Submontane to montane, wet (infrequently with a fluctuating water table), poorly aerated, and nutrient-medium and richer soils on water-collecting sitesThe SbSw – Meadow Horsetail site association, a nutrient-richer counterpart to the Sb – Tamarack site association (Figure 11), was derived from the Picea glauca & mariana – Equisetum pratense (220) plant association, and is found predominantly in the BWBSmw and BWBSwk subzones. The central edaphic concept is represented by organic soils that have developed on flat terrain and in depressions. The associated humus forms are primarily Moders (Saprimoders). No potential aberrant site types have been distinguished.Vegetation of the azonal meadow horsetail sites displays a distinct mound-depression pattern. The discontinuous and clumpy forest canopy is due to the presence of small water pools inhibiting the establishment of terrestrial vegetation, and due to windthrow. Successful regeneration and productive growth of trees is confined to drier, raised mounds of organic materials, which originated from stumps and uprooted trees. Compared to the Sb – Tamarack site association, the meadow horsetail sites are distinguished by a higher proportion of deciduous shrubs (Salix spp.), ferns and allies (Equisetum spp), graminoids (Carex spp.), and herbs (e.g., Angelica genuflexa, Mertensia paniculata, and Mitella nuda).The soil moisture spectrum of these meadow horsetail sites is dominated by the very moist to wet and wet to very wet indicator species groups (Figure 13), and is indicative of a high (about 30 cm deep) growing-season water table. The soil nutrient spectrum shows that the nitrogen-rich indicator species group is represented with the mean frequency of approximately 20%, signifiying a medium to rich SNR (Figure 12). The SbSw – Meadow Horsetail site association represents low-productivity sites for growth of white spruce, tamarack, and black spruce. The black spruce site index (50 yrs @ bh) is probably higher than 6.3 m (likely comparable to tamarack sites) but it was measured in only one of the three sampled plots. Cool soils (possibly with permafrost lenses) are thought to be the principal edaphic growth constraint. A long-lasting snow cover and somewhat restricted outflow of excess groundwater result in a nearly stagnant groundwater table. Figure 21. A dense 95 year-old (@ bh) black spruce stand in the late stem exclusion developmental stage on a wet, nutrient-medium SbSw – Meadow Horsetail site in the BWBSmw subzone. Due to very low light conditions, the understory vegetation is poorly developed.45RESULTS AND DISCUSSIONDescription of Site AssociationsMid-seral Black Spruce Ecosystems800 (Sb) – Swamp Birch site association (References: Tables 6 and 7; Figures 11, 12, and 13)Submontane to montane, very wet, very poorly aerated, nutrient-medium and richer soils on water-collecting sitesThe (Sb) – Swamp Birch site association was derived from the insufficiently sampled, tentative Picea mariana – Betula nana (310) plant association. Our sample was located in the SBSdk subzone in a depression that featured a waterlogged Humisol, with a Saprimoder. Values of the other environmental characteristics are found in Table 7. The (Sb) – Swamp Birch association represents low-productivity sites for the growth of black spruce. The Black spruce site index (50 yrs @ bh) was 9, which was within the range of the closely related the Sb – Tamarack site association. The wet to very wet indicator species group predominated in the soil moisture spectrum (Figure 13); the frequency of nitrogen-rich indicator species was >20 %, signifying a medium to rich SNR (Figure 12).  Since this tentative site association was only represented by one plot, it was not compared to site series recognized by the Ecological Program Staff of the BC Ministry of Forests.46RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityScientica Silvica Extension Series, Number 26, 2000Site Index in Relation to Ecological Measures of Site QualityFor all samples, the range of black spruce site index extended from 4.7 to 14.0 m (Table 9). Even when grouped according to various ecological measures of site quality, the within-group range of site index was wide. Analysis of variance indicated a lack of significant differences (P >0.05) in mean site index between (1) the BWBS zone and the SBS study subzones, and (2) the three subzones of the BWBS zone (Table 9). The lack of difference between the means of subzones, or even between the BWBS and SBS zone suggests that (1) climate and its variability in the studied biogeoclimatic units is similar, and (2) the precipitation difference between the subzones and zones is not likely an important growth factor. Of all other climate-related measures (elevation, latitude, longitude, aspect, and slope), only elevation was significantly, albeit weakly, related to site index (r² = 0.07, P <0.05, Eq. [1], Figure 22). A multiple linear regression showed that black spruce site index decreased 0.4 m with every 100 m increase in elevation, and 0.3 m with every one degree increase in latitude (Eq. [2], Table 10); however, although significant, this equation accounted for little of the variation about the mean (R2 = 0.13).Table 9. Summary of the black spruce site index data stratified according to selected categorical variables: biogeoclimatic zone, slope aspect, slope position, actual soil moisture regime, soil nutrient regime, and site association.Category Class Abbreviation Numberof plotsMean site index(range)Biogeoclimatic zone Boreal Black and White Spruce BWBS 60 9.8 (4.7 - 14.0)Sub-boreal Spruce SBS 22 10.2 (8.6 - 13.2)Aspect North (slope > 3%, azimuth 315°- 45°) N 13 10.1 (7.8 - 12.7)East (slope > 3%, azimuth 45°-135°) E 6 10.1 (6.1 - 13.9)South (slope > 3%, azimuth 135°-225°) S 10 9.8 (7.0 - 13.5)West (slope > 3%, azimuth 225°-315°) W 13 8.7 (4.7 - 11.6)Flat (slopes ≤ 3%) F 40 10.2 (5.2 - 14.0)Slope Flat (≤ 3%) F 40 10.2 (5.2 - 14.0)Gentle (3.1 - 10%) GL 24 9.7 (4.7 - 13.9)Moderate (10.1 - 15%) MD 8 9.7 (7.0 - 13.5)Steep (>15%) ST 10 9.4 (7.2 - 12.2)Soil order Brunisolic BRUN 8 11.3 (8.6 - 13.9)Podzolic PODZ 17 10.0 (7.4 - 14.0)Gleysolic GLEY 6 11.9 (9.5 - 13.8)Luvisolic LUV 30 10.1 (6.1 - 14.0)Organic ORG 21 8.4 (4.7 - 11.0)Actual Soil Moisture Regime (SMR)Moderately Dry MD 3 8.6 (7.3 - 9.4)Slightly Dry SD 21 10.4 (7.3 - 13.9)Fresh and Moist F/M 30 10.3 (7.0 - 14.0)Very Moist VM 20 9.0 (4.7 - 14.0)Wet W 7 9.5 (6.3 - 11.6)Very wet VW 1 9.2Soil nutrient Regime (SNR) Very poor VP 18 8.8 (4.7 - 13.2)Poor P 33 9.2 (6.1 - 13.5)Medium MED 21 11.3 (9.1 - 14.0)Rich R 9 10.7 (6.3 - 14.0)Very rich VR 1 11.6Site association SbPl - Lichens SA100 4 8.9 (7.3 - 9.9)SbPl - Moss SA200 15 9.7 (7.3 - 13.5)Sb - Wood Horsetail SA300 25 8.6 (4.7 - 11.5)Sb - Tamarack SA400 7 9.6 (6.9 - 11.6)SbSw - Soopalallie SA500 6 12.1 (10.4 - 13.9)SbSw - Common Mitrewort SA600 23 11.2 (7.8 - 14.0)SbSw - Meadow Horsetail SA700 1 6.3(Sb) - Swamp Birch SA800 1 9.247RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityMid-seral Black Spruce EcosystemsFigure 22. Black spruce site index in relation to elevation. The fitted regression line is Site Index = 12.08 - 0.2683 (elevation); R2 = 0.07, standard error of estimates 2.03 m, P <0.01.Table 10. Regression models for predicting black spruce site index from climatic and edaphic variables (n = 78).  The abbreviations for the variables are: SI = site index; ELEV = elevation (100 m); LAT = latitude; SEE = standard error of the estimate.Factors Model Padj-R² SEE[1] elevation SI = 12.08 - 0.2683(ELEV) 0.0068 0.07 2.03[2] elevation,latitudeSI = 33.3999 - 0.3510(LAT) - 0.4261(ELEV) 0.0028 0.12 1.99[3] soil order SI = 8.45 + 2.83(BRUN) + 3.45(GLEY) + 1.56(LUV) + 1.76(PODZ) 0.0006 0.19 1.91[4] soil order, elevationSI = 10.81 + 2.85 (BRUN) + 2.65(GLEY)  2.19(LUV) + 2.40(PODZ) - 0.33(ELEV) 0.0001 0.28 1.79[5] SNR SI = 8.84 + 0.43(P) + 2.65(MED) + 2.45(R) 0.0001 0.25 1.83[6] SNR, elevationSI = 10.80 + 0.77(P) + 2.69(MED) + 2.79(R) - 0.27(ELEV) 0.0001 0.33 1.73[7] SMR SI = 9.25 +1.19(SD) + 1.02(F/M) - 0.28(VM) + 0.84(W) 0.1772 0.03 2.09[8] SMR, elevationSI = 13.32 + 0.58(SD) + 0.44(F/M) - 1.45(VM) - 1.13(W) - 0.40(ELEV) 0.0010 0.19 1.91[9] SMR, SNR SI = 9.25 - 0.22(SD) - 0.82(F/M) - 1.22(VM) + 0.62(W) + 0.45(P) + 3.05(MED) + 2.34(R) 0.0001 0.31 1.76[10] SMR, SNR, elevationSI = 12.51 - 0.44(SD) -1.33(F/M) - 2.24(VM) - 1.12(W) + 0.76(P) + 2.87(MED) + 2.45(R) - 0.33(ELEV)0.0001 0.40 1.63[11] SMR, SNR, SMR×SNRSI = 9.25 + 1.35(SD) - 0.97(F/M) - 1.70(VM) + 0.34(W) - 1.10(P) + 2.54(MED) + 0.98(R) + 2.16(F/M×P) + 0.35(F/M×MED) + 1.75(F/M×R) + 1.92(VM×P) + 1.91(VM×MED) + 2.10(W×P)0.0003 0.30 1.77[12] SMR, SNR, SMR×SNR, elevationSI = 13.00 + 1.01(SD) - 2.27(F/M) - 2.82(VM) - 1.89(W) - 1.18(P) +1.25(MED) + 0.61(R) + 3.38(F/M×P) + 2.10(F/M×MED) + 3.01(F/M×R) + 2.18(VM×P) + 2.98(VM×MED) + 3.01(W×P)- 0.37(ELEV)0.0001 0.42 1.59[13] site association SI = 9.46 + 0.23(SA200) - 0.83(SA300) + 0.17(SA400) + 2.61(SA500) + 1.75(SA600) 0.0001 0.26 1.82[14] site association, elevationSI = 12.08 + 0.06(SA200) - 1.25(SA300) - 0.87(SA400) + 2.02(SA500) + 1.28(SA600) - 0.27(ELEV)0.0001 0.34 1.7234567891011121314150 200 400 600 800 1000 1200 1400Elevation (m)Site index (m @ 50 years at bh)48RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityScientica Silvica Extension Series, Number 26, 2000Analysis of variance detected significant differences (P <0.05) in site index between soil orders (Figure 23). Site index of black spruce increased in order from Organics to Podzols to Luvisols to Brunisols to Gleysols, with Brunisols and Gleysols having significantly higher site index than Organics (Table 9). Site index of black spruce on Organics (typically poorly aerated, water-surplus soils) was 1.8 m lower, and on Gleysols (typically non-water deficient and nutrient-richer sites) 1.7 m higher, than the mean of the other soil orders combined. These relationships are complex because several edaphic factors such as soil moisture (drainage), nutrients, aeration, and temperature are integrated into soil orders.The black spruce site index did not differ significantly along the soil moisture gradient (which was confounded with the soil nutrient gradient). Examination of the trend of black spruce site index along the soil nutrient gradient (albeit confounded with the soil moisture gradient) showed an increase from the very poor to poor to medium sites (Figure 24). Significant differences occurred only between medium and very poor sites, while poor and rich sites were not significantly different from either very poor or medium sites. The site index on sites with a medium SNR was 1.6 m higher than the mean site index for all other SNRs combined. The lack of significant differences in site index between soil moisture regimes suggests that within a boreal climate shallow-rooted black spruce is not growth-sensitive to soil moisture. The narrow range in site index between very poor and rich sites suggests that black spruce is marginally growth-sensitive to an increasing supply of soil nutrients within a boreal climate. The pattern of predicted site index placed on the edatopic gird (Table 11) emphasized the relatively small differences in site index between soil moisture and nutrient conditions. This suggests that one or more factors not measured in this study has an overriding influence on tree growth.Among the five site associations that could be tested, significant differences (P <0.05) in site index were detected only between the Sb - Wood Horsetail association (mean site index of 8.6 m) and the SbSw - Soopolallie and SbSw - Common Mitrewort associations (mean site index of 12.1 and 11.2 m, respectively); there were no significant differences in site index between the SbPl - Lichens, SbPl - Moss, and Sb - Tamarack associations (Table 9, Figure 25). Black spruce site index on the SbSw - Soopolallie sites was 3 m higher, and on the SbSw - Common Mitrewort sites 2.1 m higher, than the mean of all other site associations combined. Regardless of moisture, site index appeared to increase from nutrient-poorer to -richer sites as illustrated by comparing moisture-equivalent associations: SbPl - Moss versus SbSw - Soopolallie and Sb - Wood Horsetail versus SbSw - Common Mitrewort site associations. The Sb - Wood Horsetail site association reflects adverse soil moisture, nutrient, aeration, and temperature conditions, while the SbSw - Soopolallie site association reflects the optimum soil aeration, temperature, and nutrient conditions for black spruce growth.In addition to the two climate models, twelve regression models using a combination of variables related to soil conditions (with or without elevation) were developed to quantify site index-site quality relationships, and to determine the precision of the predictions of black spruce site index (Eqs. [3] to [14], Table 10). Except for model [7], which used only SMRs, the remaining models were significant at P <0.01. The addition of elevation into the models decreased the SEE and increased the R² in all cases (compare equations [3] and [4]; [5] and [6]; [7] and [8]; [9] and [10]; [11] and [12]; [13] and [14]). There were three groupings of precision: models [10] and [12] had the lowest SEE and highest R²; followed by models [6] and [14]. Finally, models [9], [11], and [13] are at the limits of acceptable precision. As the average site index for the edatopic grid is around 10 m, the SEE from our best regression of 1.59 m is about 16% of the average site index. The mean site index predicted by equation [9] (Table 10) for combinations of soil moisture and nutrient regimes and the confidence and prediction intervals were placed on the edatopic grid of the BEC system (Table 11).49RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityMid-seral Black Spruce EcosystemsFigure 23. Black spruce site index in relation to soil orders. Error bars are one standard error of the mean; the numbers in bars are numbers of sample plots; bars with the same lowercase letter are not significantly different (P < 0.05; Tukey's test).Figure 24. Black spruce site index in relation to soil nutrient regime (SNR).  Abbreviations for SNRs as in Table 1. Error bars are one standard error of the mean; the numbers in bars are numbers of sample plots; bars with the same lowercase letter are not significantly different (P < 0.05; Tukey's test).Figure 25. Black spruce site index in relation to site associations. Abbreviations for site associations as in Ta bl e 1 . Error bars are one standard error of the mean; the numbers in bars are numbers of sample plots; bars with the same lowercase letter are not significantly different (P < 0.05; Tukey's test).Soil order02468101214Site index (m @ 50 ys. bh age)Organic Podzol Luvisol Brunisol Gleysolaabab b21 17 30 8 6bVP P M R VRSoil nutrient regime024681012Site index (m @ 50 ys. bh age)aab b ab18 33 21 9 1Site associationSite index (m @ 50 ys. bh age)02468101214100 200 300 400 500 600 700 800415257 6231 1ab ab a ab b b50RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityScientica Silvica Extension Series, Number 26, 2000The use of soil moisture and nutrient regimes for quantifying site index relationships has once again shown to be useful. In the case of the BWBS zone however, elevation appears to be a useful surrogate for climate, reflecting an increase in site index with increasing temperature. Although the coefficients of determination for the regression models for black spruce are lower compared to other to cool temperate and mesothermal tree species, this was probably simply due to the small range of mean site index. The smallest predicted site index for any cell on the edtopic grid was 8.03 m and the largest site index was 12.53 m  (Table 11). This range is very small when compared to coastal Douglas-fir (Pseudotsuga menziesii), for example, in comparable SMRs and SNRs site index ranges from 20 to 40 (Klinka and Carter 1990). However, our SEE is relatively large compared to other regression models developed for other species of BC. Generally, the SEEs are in the range of 10% of the average site index for the respective edatopic grids, whereas for black spruce the SEE is 16% of the average site index. The prediction intervals are rather large, thus limiting the applicability of the models in predicting the future site index of a given stand based on soil moisture and nutrient regime. However, the model describes the mean site index well across the edatopic grid.Two other studies, by Krajina (1969) and the BC Ministry of Forests (1997), have quantified site index across the edatopic grid in the BWBS zone. The values in this study are close to those of Krajina (1969), who also suggested very low site index values. The highest site index for black spruce in the BWBS zone was 15 m in 100 years, which is reasonable compared to our 50 year base age site index values. However, Krajina (1969) proposed that the largest mean site index value would occur on very moist/poor sites, whereas this study suggests the largest site index occurs on slightly dry/medium sites. Direct comparisons with BC Ministry of Forests SIBEC data is difficult, since we used actual SMRs as opposed to the relative SMRs used by the Ministry of Forests, and our site associations differ from theirs.  However, the SIBEC site index values for the BWBSdk1 and 2 variants are generally in the low range (around 10), while the site index values of 15 for the BWBSmw1 and 2 variants seem too high. The site index values of the BWBS zone for black spruce are rated as having low reliability; therefore we suggest that the site index values of 15 be replaced with our highest estimates for site index of 12.Regional differences in black spruce site index have been attributed to climatic factors, and differences within regions to soil moisture and soil nutrients (Viereck and Johnston 1990). Jeglum (1974) found site index to be predominantly related to the moisture-aeration regime, and on waterlogged organic soils, water movement and chemistry appear to be most important growth determinants (Heinselman 1970). However, this study suggests that neither climate, soil moisture regime, nor soil nutrient regime accounts satisfactorily for differences in site index on different sites. It is likely that soil temperature is the most influential growth factor in the BWBS zone, and this requires further investigation.51RESULTS AND DISCUSSIONSite Index in Relation to Ecological Measures of Site QualityMid-seral Black Spruce EcosystemsTable 11. Mean site index (m @ 50 years breast height age), 95% confidence interval (m), 95% prediction interval (in parentheses), and sample size for each combination of SMR and SNR for black spruce in the BWBS zone using equation [9] (See Table 10).Soil nutrient regimevery poor poor medium richActual Soil moisture regimemoderatelydry9.25±2.49(±4.31)n = 2slightlydry9.47 9.92 12.53 11.81±1.16 ±0.88 ±1.18 ±1.35(±3.71) (±3.63) (±3.71) (±3.77)n = 4 n = 11 n = 2 n = 4fresh -moist8.43 8.88 11.49 10.77±1.20 ±0.88 ±0.85 ±1.35(±3.72) (±3.63) (±3.62) (±3.77)n = 2 n = 10 n = 13 n = 4verymoist8.03 8.48 11.09±1.05 ±0.95 ±1.11(±3.67) (±3.64) (±3.69)n = 7 n = 8 n = 5wet9.87 10.32±1.54 ±1.54(±3.84) (±3.84)n = 3 n = 352REFERENCESScientica Silvica Extension Series, Number 26, 2000REFERENCESAgriculture Canada Expert Committeee on Soil Survey. 1987. The Canadian system of soil classification. 2nd ed. Agric. Can. Publ. 1646. Agriculture Canada, Ottawa, ON. 164 pp.Annas, R.M. 1974. Ecosystems of the Fort Nelson area of north-eastern British Columbia. Ph.D. thesis Fac. For., Univ. B.C., Vancouver, B.C.Banner, A., W. MacKenzie, S. Haeussler, S. Thomson, J. Pojar, and R. Trowbridge. 1993. A field guide to site identification and interpretation for the Prince Rupert Forest Region. Land Management Handbook No 26. B.C. Min. For., Victoria, B.C. Barkman, J.J., J. Moravec, and S. Rauschert. 1976. Code of phytosociological nomenclature. Vegetatio 32:131-185.BC Ministy of Forests. 1987. Biogeoclimatic units of the Prince George Forest Region. Map, scale 1:800,000. B.C. Min. For., Prince George, B.C.BC Ministy of Forests. 1988. Biogeoclimatic and ecoregion unit of the Prince Rupert Forest Region. Map, scale 1:500,000. B.C. Min. For., Prince George, B.C.BC Ministry of Forests. 1997. Site index estimates by site series for coniferous tree species in British Columbia. Forest Renewal BC and BC Ministry of Forests, Victoria, B.C. 265 pp.Becking, R.W. 1957. The Zurich-Montepellier School of Phytosociology. Bot. Rev. 23:411-488.Brooke, R.C., E.B. Peterson, and V.J. Krajina. 1970. The subalpine Mountain Hemlock zone. Ecol. Western N. Amer. 2:148-349.Carmean, W.H. 1972. Site index curve for upland oaks in the Central States. For. Sci. 18:109-120.Carmean, W.H. 1975. Forest site quality evaluation in the United States. Adv. Agron. 27:209-269.Chen, H.Y.H., K. Klinka, and R.D. Kabzems. 1998. Site index, site quality, and foliar nutrients of trembling aspen: relationships and predictions. Can. J. For. Res. 28:1743-1755.DeLong, C., A. MacKinnon, and L. Jang. 1990. A field guide for identification and interpretation of ecosystems of the northeast portion of the Prince George Forest Region. Land Management Handbook No. 22, B.C. Min. For., Victoria, B.C.Dyer, M.E. and Bailey, R.L. 1987. A test of 6 methods of estimating true heights from stem analysis data. For. Sci. 33:3-13.Emanuel, J. 1999. VTAB Ecosystem Reporter Revision 199907a. Department of Forest Sciences, University of British Columbia, Vancouver, B.C. Green, R.N. and K. Klinka. 1994. A field guide to site identification and interpretation for the Vancouver Forest Region. B.C. Min. For., Victoria, B.C. 285 pp.Green, R.N., R.L. Towbridge, and K. Klinka. 1993. Towards a taxonomic classification of humus forms. For. Sci. Monog. 29. 49pp.53REFERENCESMid-seral Black Spruce EcosystemsHeinselman, M.L. 1970. Landscape evolution, peatland types and the environments in the Lake Agassiz Peatland Natural Area, Minnesota. Ecol. Monogr. 40:253-261.Hill, M.O. 1979. TWINSPAN - a FORTRAN program for arranging multivariate data in an ordered two-way table by classification of the individuals and attributes. Cornell University, Ithaca, N.Y.Jeglum, J.K. 1974. Relative influence of moisture, aeration and nutrients on vegetation and black spruce growth in northern Ontario. Can. J. For. Res. 4:114-125.Kayahara, G.J., K. Klinka, P.V. Krestov, and H. Qian. 2000. submitted manuscript: Comparison of vegetation, forest floors, and mineral soil properties between black spruce (Picea mariana) and trembling aspen (Populus tremuloides) stands in the boreal forest of British Columbia.Kayahara, G.J. and A.F. Pearson. 1996. Site index of western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis) in relation to soil moisture regimes and soil nutrient regimes. Work. Pap. 17/1996. Res. Br., B.C. Min. For., Victoria, B.C. Kayahara, G.J., K. Klinka, and P.L. Marshall. 1998. Testing site index-site factor relationships for predicting Pinus contorta and Picea engelmannii × P. glauca productivity in central British Columbia, Canada. For. Ecol. Manage. 110: 141-150.Kayahara, G.J., K. Klinka, and A. Schroff. 1997. The relationship of site index to synoptic estimates of soil moisture and nutrients for western redcedar (Thuja plicata) in southern coastal British Columbia. NW Sci. 71: 167-173.Kayahara, G.J., K. Klinka, and I. Moss. 1995. Site index - site quality relationships for lodgepole pine, interior spruce, and subalpine fir in the Sub-boreal Spruce zone of British Columbia. Contract report for Northwood Pulp and Timber Ltd, Prince George, British Columbia.Klinka, K., H. Qian, J. Pojar, and D.V. Meidinger. 1996. Classification of natural forest communities of coastal British Columbia, Canada. Vegetatio 125: 149-168.Klinka, K. and R.E. Carter. 1990. Relationships between site index and synoptic environmental factors in immature coastal Douglas-fir stands. For. Sci. 36:815-830.Klinka, K., V.J. Krajina, A. Ceska and A.M. Scagel. 1989. Indicator plants of coastal British Columbia. University of British Columbia Press, Vancouver, B.C. 138 pp.Krajina, V.J. 1969. Ecology of forest trees in British Columbia. Ecol. Western N. Amer. 2:1-146.Luttmerding, H.A, D.A. Demarchi. E.C. Lea, D.V. Meidinger and T. Vold (eds.) 1990. Describing ecosystems in the field. 2nd ed. B.C. Min. For., Victoria, B.C.MacKinnon, A., C. DeLong, and D. Meidinger. 1990. A field guide for identification and interpretation of ecosystems of the northwest portion of the Prince George Forest Region. Land Management Handbook No. 21. B.C. Min. For., Victoria, B.C.Magurran, A.E. 1988. Ecological diversity and its measurement. Princeton University Press, Princeton, N.Y. 179 pp.Meidinger, D.V. and J. Pojar (eds.) 1991. Ecosystems of British Columbia. Special Rep. Series no. 6, B.C. Min. For., Victoria, B.C.Monserud, R.A. 1984. Height growth and site index curves for inland Douglas-fir. Can. J. For. Res. 20:686-695.54REFERENCESScientica Silvica Extension Series, Number 26, 2000Mueller-Dombois, D., and H. Ellenberg. 1974. Aims and methods of vegetation ecology. John Wiley and Sons, Toronto, ON.Nigh, G.D. 1996. Growth intercept models for species without distinct annual branch whorls: western hemlock. Can. J. For. Res. 26:1407-1415.Nigh, G.D. and V. Sit. 1996. Validation of forest height-age models. Can. J. For. Res. 26:810-818.Pojar, J. , K. Klinka and D.V. Meidinger. 1987. Biogeoclimatic ecosystem classification in British Columbia. For. Ecol. Manage. 22:119-154.Poore, M.E.D. 1962. The methods of successive approximation in descriptive ecology. Adv. Ecol. Res. 1:35-68.Qian, H. and K. Klinka. 1998. Plants of British Columbia: Scientific and common names of vascular plants, bryophytes, and lichens. University of British Columbia Press, Vancouver, B.C. 534pp.Qian, H., K. Kinka, and B. Sivak. 1997. Diversity of the understory vascular vegetation in 40 year-old and old-growth forest stands on Vancouver Island, British Columbia. J. Veg. Sci. 8:773-780.Revel, R.D. 1972. Phytogeocoenoses of the Sub-boreal Spruce biogeoclimatic zone in north central British Columbia.  Ph.D. thesis, Fac. For., Univ. B.C. Vancouver, B.C.Smith, D.M. 1986. The practice of silviculture. 8th Edition. John Wiley and Sons, New York. 527 pp.Viereck, L.A. and W.F. Johnston. 1990. Picea mariana (Mill.) B.S.P. - Black Spruce. In Burns, R.M. and B. H. Honkala, (eds). Silvics of North America: Vol. 1. Conifers. USDA For. Serv., Agricultural Handbook 654, Washington, D.C. USA. pp. 227-237.Wali, M.K. and V.J. Krajina. 1973. Vegetation-environment relationships of some Sub-boreal Spruce zone ecosystems in British Columbia. Vegetatio 26:237-381.Wang, Q. 1992. Ecological and height growth analysis of some sub-boreal immature lodgepole pine stands in central British Columbia. Ph.D. thesis, Fac. For., Univ. B.C. Vancouver, B.C. 207 pp.Wang, G.G. and K. Klinka. 1996. Use of synoptic variables in predicting white spruce site index. For. Ecol. Manage. 80:95-105.Wang, Q., G.G. Wang, K.D. Coates, and K. Klinka. 1994. Use of site factors to predict lodgepole pine and interior spruce site index in the Sub-Boreal Spruce Zone. Research Note No. 114, B.C. Min. For., Victoria, B.C.Westhoff, V. and E. van der Maarel. 1980. The Braun-Blanquet approach. In: R.H. Whittaker (ed). Classification of Plant Communities. Edited by R.H. Whittaker. Dr. Junk bv Publishers, The Hague.55APPENDICESAppendix 1Mid-seral Black Spruce EcosystemsAPPENDICESAppendix 1. List of all plant species (arranged alphabetically) found in the mid-seral black spruce ecosystems in northern British Columbia sampled in this study. Scientific nomenclature follows Qian and Klinka (1998).Scientific name Common name AuthorityAbies lasiocarpa subalpine fir (Hook.) Nutt. Achillea millefolium yarrow L.Actaea rubra baneberry (Ait.) Willd.Agrostis mertensii northern bentgrass Trin. Alectoria sarmentosa common witch's hair (Ach.) Ach. Alnus incana (=Alnus tenuifolia) gray alder (L.) MoenchAlnus viridis  green alder (Vill.) Lam & D.C.Amblystegium riparium  (Hedw.) SchimpAmelanchier alnifolia saskatoon (Nutt.) Nutt. ex M. Roemer Anemone parviflora northern anemone Michx. Angelica genuflexa kneeling angelica Nutt. Antennaria racemosa racemose pussytoes Hook. Aquilegia formosa red columbine Fisch. ex DC. Aralia nudicaulis wild sarsaparilla L. Arctostaphylos alpina alpine bearberry (L.) Spreng. Arctostaphylos uva-ursi kinnikinnick (L.) Spreng.Arnica cordifolia heart-leaved arnica Hook. Aster ciliolatus Lindley's aster Lindl. Aster conspicuus showy aster Lindl. Aster modestus great northern aster Lindl. Aster sibiricus arctic aster L. Aulacomnium palustre glow moss (Hedw.) Schwaegr. Barbilophozia hatcheri  (Evans) LoeskeBarbilophozia kunzeana Hub.) Gams. Betula nana (=Betula glandulosa) swamp birch L.Betula papyrifera paper birch Marsh. Brachythecium spp.  ragged moss  Bryum spp.    Calamagrostis canadensis bluejoint (Michx.) Beauv.Calamagrostis rubescens pinegrass Buckl.Calliergon cordifolium  (Hedw.) Kindb. Calliergon giganteum giant water moss (Schimp.) Kindb. Calliergon stramineum  (Brid. Kindb.Calypso bulbosa fairyslipper (L.) Oakes Campylium stellatum  (Hedw.) C. Jens.Carex concinna low northern sedge R. Br. Carex disperma soft-leaved sedge Dewey Carex rossii Ross' sedge Boott Carex spectabilis showy sedge Dewey Carex spp.  sedge  Castilleja miniata scarlet paintbrush Dougl. ex Hook. Cetraria ericetorum icelandmoss OpizCinna latifolia nodding wood-reed (Trev. ex Goepp.) Griseb. Cladina arbuscula  (Wallr.) Hale & Culb. Cladina rangiferina grey reindeer lichen (L.) Nyl. Cladina stellaris Opiz) Brodo Cladonia cenotea powdered pixie-funnel (Ach.) Schaerer Cladonia cervicornis  (Ach.) FlotowCladonia chlorophaea peppered pixie-cup (Färke ex Sommerf.) Sprengel Cladonia cornuta greater pixie stick (L.) Hoffm. Cladonia crispata  (Ach.) FlotowCladonia ecmocyna orange-footed pixie Leighton Cladonia gracilis  (L.) Willd.Cladonia multiformis slotted pixie-cup G. Merr. Cladonia phyllophora  Hoffm.Cladonia sulphurina sulphur cladonia (Michaux) Fr. Cladonia uncialis  (L.) F. H. Wigg. Clintonia uniflora queen's cup (Menzies ex J.A. & J.H. Schultes) Kunth Coeloglossum viride long-bracted frog orchid (L.) Hartman 56APPENDICESAppendix 1Scientica Silvica Extension Series, Number 26, 2000Comandra umbellata California comandra (L.) Nutt. Coptis trifolia three-leaved goldthread (L.) Salisb.Corallorhiza trifida yellow coralroot Chatelain Cornus canadensis bunchberry L.Cornus stolonifera red-osier dogwood Michx. Cystopteris montana mountain bladder fern (Lam.) Bernh. ex Desv. Delphinium glaucum tall larkspur S. Wats. Dicranella palustris  (Dicks.) Crundw. ex Warb.Dicranum affine  FunckDicranum fuscescens curly heron's-bill moss Turn. Dicranum polysetum wavy-leaved moss Sw. Dicranum scoparium broom moss Hedw. Dicranum spp.    Disporum hookeri Hooker's fairybells (Torr.) Nichols. Distichium capillaceum  (Hedw.) Bruch & Schimp.Drepanocladus exannulatus  (Schimp. Warnst.Drepanocladus uncinatus sickle moss (Hedw.) Warnst. Drosera rotundifolia round-leaved sundew L. Elliottia pyroliflorus (=Cladothamnus pyroliflorus) copperbush (Bong.) S.W. Brim & P.F. Stevens Elymus glaucus blue wildrye Buckl. Elymus repens quackgrass (L.) Gould Empetrum nigrum crowberry L.Epilobium angustifolium fireweed .Epilobium ciliatum purple-leaved willowherb Raf. Epilobium glaberrimum smooth willowherb Barbey Equisetum arvense common horsetail L. Equisetum fluviatile swamp horsetail L. Equisetum pratense meadow horsetail Ehrh. Equisetum scirpoides dwarf scouring-rush Michx. Equisetum sylvaticum wood horsetail L. Eriophorum angustifolium narrow-leaved cotton-grass Honckeny Eurhynchium pulchellum  (Hedw.) Jenn.Evernia mesomorpha spruce moss Nyl. Festuca altaica Altai fescue Trin. Festuca occidentalis western fescue Hook. Flavocetraria nivalis ragged snow (L.) Kärnefelt & Thell Fragaria virginiana wild strawberry Duchesne Frangula purshiana (=Rhamnus purshiana) cascara (D.C.) CooperGalium bifolium thin-leaved bedstraw S. Wats. Galium boreale northern bedstraw L. Galium triflorum small bedstraw L. Gentianella amarella northern gentian (L.) Boerner Geocaulon lividum bastard toad-flax (Richards.) Fern. Geum macrophyllum large-leaved avens Willd. Goodyera oblongifolia rattlesnake-plantain Raf.Goodyera repens dwarf rattlesnake orchid (L.) R. Br. ex Ait. f. Gymnocarpium dryopteris oak fern (L.) Newman Heracleum maximum  cow-parsnip Bartr.Hylocomium splendens step moss (Hedw.) Schimp. Hypogymnia austerodes powdered bone (Nyl.) Räsänen Hypogymnia physodes monk's-hood (L.) Nyl.Icmadophila ericetorum spraypaint (L.) Zahlbr.Impatiens noli-tangere common touch-me-not L. Jungermannia leiantha  GrolleJuniperus communis common juniper L. Larix laricina tamarack (Du Roi) K. Koch Lathyrus nevadensis purple peavine S. Wats. Lathyrus ochroleucus creamy peavine Hook. Ledum groenlandicum Labrador tea Oeder Leymus innovatus fuzzy-spiked wildrye (Beal) Pilger Linnaea borealis twinflower L.Listera cordata heart-leaved twayblade (L.) R. Br. ex Ait. f. Lonicera involucrata black twinberry (Richards.) Banks ex Spreng. Lonicera utahensis Utah honeysuckle S. Wats. Scientific name Common name Authority57APPENDICESAppendix 1Mid-seral Black Spruce EcosystemsLupinus arcticus arctic lupine S. Wats. Luzula parviflora small-flowered woodrush (Ehrh.) Desv. Lycopodium annotinum stiff clubmoss L. Lycopodium complanatum ground-cedar L.Lycopodium dendroideum ground-pine Michx.Lysichiton americanum skunk cabbage Hult. & St. John Maianthemum canadense wild lily-of-the-valley Desf. Maianthemum racemosum (=Smilacina racemosa)  False Solomon's seal (L.) Link Maianthemum stellatum (=Smilacina stellata) star-flowered false Solomon's seal (L.) LinkMaianthemum trifolium (=Smilacina trifolia) three-leaved false Solomon's seal (L.) SlobodaMalaxis brachypoda   (Gray) Fern.Menyanthes trifoliata buckbean L.Menziesia ferruginea false azalea Sm. Mertensia paniculata tall bluebells (W. Ait.) G. Don Mitella nuda common mitrewort L. Mnium spinulosum  Menzies' red-mouthed mnium Bruch & Schimp. in B.S.G.Moneses uniflora single delight (L.) A. Gray Nephroma arcticum green light (L.) Torss. Orthilia secunda one-sided wintergreen (L.) House Oryzopsis asperifolia rough-leaved ricegrass Michx. Osmorhiza berteroi (=Osmorhiza chilensis) mountain sweet-cicely D.C. Oxycoccus oxycoccos bog cranberry (L.) MacM. Parmelia sulcata waxpaper TaylorParnassia palustris northern grass-of-Parnassus L. Pedicularis bracteosa bracted lousewort Benth. Pedicularis labradorica Labrador lousewort Wirsing Peltigera aphthosa freckle pelt (L.) Willd. Peltigera malacea apple pelt (Ach.) Funck Peltigera membranacea greater dog pelt (Ach.) Nyl. Peltigera neopolydactyla greater frog pelt (Gyelnik) Gyelnik Peltigera praetextata born-again pelt (Färke ex Sommerf.) Zopf Peltigera scabrosa toad pelt Th. Fr. Pentaphylloides floribunda (=Potentilla fruticosa) Shrubby cinqfoil (Pursh.) A. Löve Petasites frigidus sweet coltsfoot (L.) Fries Petasites sagittatus arrow-leaved coltsfoot (Banks ex Pursh) A. Gray Phleum alpinum alpine timothy L. Picea glauca white spruce (Moench) Voss Picea mariana black spruce (P. Mill.) B.S.P. Pinus contorta lodgepole pine Dougl. ex Loud. Plagiochila aspleniformis  Schust. Plagiomnium ciliare  (C. Müll.) Kop. Plagiomnium ellipticum  (Brid.) T. Kop.Platanthera obtusata one-leaved rein orchid (Banks ex Pursh) Lindl. Platanthera orbiculata large round-leaved rein orchid (Pursh) Lindl. Pleurozium schreberi red-stemmed feathermoss (Brid.) Mitt. Poa spp.  bluegrass  Pohlia spp.  Polemonium caeruleum tall Jacob's-ladder L. Polytrichum commune  Hedw.Polytrichum juniperinum juniper haircap moss Hedw. Polytrichum piliferum awned haircap moss Hedw. Polytrichum strictum bog haircap moss Brid. Populus balsamifera balsam poplar L. Populus tremuloides trembling aspen Michx. Ptilidium pulcherrimum  (G. Web.) HampePtilium crista-castrensis  (Hedw. De Not.Pulsatilla patens(=Anemone patens)  prairie crocus (L.) P. Mill Pyrola asarifolia pink wintergreen Michx. Pyrola chlorantha green wintergreen Sw. Pyrola elliptica white wintergreen Nutt. Pyrola minor lesser wintergreen L. Ranunculus eschscholtzii subalpine buttercup Schlecht. Rhizomnium glabrescens  fan moss (Kindb.) T. Kop Rhizomnium pseudopunctatum  (Bruch & Schimp.)T. Kop.Scientific name Common name Authority58APPENDICESAppendix 1Scientica Silvica Extension Series, Number 26, 2000Rhytidiadelphus triquetrus electrified cat's-tail moss (Hedw.) Warnst. Ribes hudsonianum northern blackcurrant Richards. Ribes lacustre black gooseberry (Pers.) Poir. Ribes triste red swamp currant Pallas Rosa acicularis prickly rose Lindl. Rubus chamaemorus cloudberry L.Rubus idaeus red raspberry L. Rubus parviflorus thimbleberry Nutt. Rubus pedatus five-leaved bramble Sm. Rubus pubescens trailing raspberry Raf. Salix bebbiana Bebb's willow Sarg. Salix glauca grey-leaved willow L. Salix lucida shining willow Muhl. Salix myrtillifolia bilberry willow Anderss. Salix scouleriana Scouler's  willow Barratt ex Hook. Salix spp.  willow  Sambucus racemosa red elderberry L. Sanguisorba canadensis Sitka burnet L. Senecio triangularis arrow-leaved groundsel Hook. Shepherdia canadensis soopolallie (L.) Nutt.Solidago spathulata spike-like goldenrod DC. Solorina crocea chocolate chip (L.) Ach. Sorbus scopulina western mountain-ash Greene Sphagnum capillifolium small red peat moss (Ehrh.) Hedw. Sphagnum fuscum rusty peat moss (Schimp.) Klinggr. Sphagnum girgensohnii white-toothed peat moss Russ. Sphagnum magellanicum midway peat moss Brid. Sphagnum palustre  L.Sphagnum rubellum  Wils.Sphagnum spp.  Peat moss  Sphagnum squarrosum Spread-leaved peat moss Crome Sphagnum warnstorfii Warnstorf's peat moss Russ. Spiraea betulifolia birch-leaved spirea Pallas Spiraea douglasii hardhack Hook.Spiraea pyramidata pyramid spirea Greene Splachnum sphaericum  Hedw.Stellaria calycantha northern starwort (Ledeb.) Bong. Stereocaulon paschale cottontail coral (L.) Hoffm. Stereocaulon tomentosum woolly coral Fr. Streptopus amplexifolius clasping twistedstalk (L.) DC. Symphoricarpos albus common snowberry (L.) Blake Thalictrum occidentale western meadowrue A. Gray Thamnolia vermicularis rockworm (Sw.) Ach. ex Schaerer Tiarella trifoliata three-leaved foamflower L. Tomentypnum nitens golden fuzzy fen moss (Hedw.) Loeske Torreyochloa pallida Fernald's false-manna (Torr.) Church Trientalis europaea  European starflower L. Trimorpha acris (=Erigeron acris)  bitter fleabane  (L.) NeesonTrisetum cernuum nodding trisetum Trin. Trisetum spicatum spike trisetum (L.) Richter Tritomaria exsectiformis  (Breidl.) LoeskeUsnea spp.  witches' hair  Vaccinium caespitosum dwarf blueberry Michx. Vaccinium membranaceum black huckleberry Dougl. ex Torr. Vaccinium scoparium grouseberry Leib. ex Coville Vaccinium uliginosum bog blueberry L. Vaccinium vitis-idaea lingonberry L.Veratrum viride Indian hellebore Ait. Veronica beccabunga American speedwell L. Viburnum edule highbush-cranberry (Michx.) Raf. Viola canadensis Canada violet L. Viola orbiculata rounded-leaved violet Geyer ex Holz. Viola palustris marsh violet L. Viola renifolia kidney-leaved violet A. Gray Zigadenus elegans mountain death-camas Pursh Scientific name Common name Authority59APPENDICESAppendix 2Mid-seral Black Spruce EcosystemsAppendix 2. Summary table of vegetation units. This table presents only the plant species (in alphabetical order) occurring in ≤40% of plots in all vegetation units (presence class ≤II). Weak diagnostic species (usually important companion species) used in the diagnostic combinations of species (Table 2) are shaded in gray.Vegetation unit Code 110 120 131 132 211 212 220 310Number of plant species 52 129 128 108 107 152 68 16Number of sample plots 5 25 34 13 13 28 3 1Species Species presence and significance1Actaea rubra     I     h  II    1  II    +   Agrostis mertensii       I  t   Alectoria sarmentosa    I     t      Alnus incana    I t  I     + II  4  I     +  II    2  II    4  Alnus viridis   I 5  I  2  I     2  I     2  I     3  I     2   Amblystegium riparium     I     h     Amelanchier alnifolia      II    2  I     h   Anemone parviflora    I     t  II    h  I     h   II    h  Antennaria racemosa   I     t       Aquilegia formosa      I  h    Aralia nudicaulis       I  h   Arctostaphylos alpina   I     +  I     +  I     +  I     h    Arctostaphylos uva-ursi  II    4   I     +      Aster conspicuus     I     h  II    3  I     h   Aster modestus       I  t   Aster sibiricus   I     h  I     h   I     h  II    h   Barbilophozia hatcheri   I     t       Barbilophozia kunzeana  I     h        Betula papyrifera    I     +  I     2   I     1   Brachythecium spp.    I     4       Calamagrostis canadensis   I     t  I     +  II    h  I     h  II    +  II    6  Calamagrostis rubescens   I     t       Calliergon cordifolium       I  +   Calliergon giganteum    I     +      Calliergon stramineum     I     h    II    h  Calypso bulbosa    I     t    I     t   Campylium stellatum       I  h   Carex concinna       I  t   Carex rossii       I  h  II    h  Carex spectabilis    I     t      Carex spp.        I  +   Castilleja miniata      I  h    Cetraria ericetorum   I     h       Cinna latifolia    I     h   I     h  I     h   Cladina arbuscula  I     2  I     4  I     1  I     h  I     h  I     h   Cladina rangiferina  I     1  I     +       Cladonia cenotea   I     t       Cladonia cervicornis    I     t      Cladonia chlorophaea   I     h       Cladonia cornuta   I     h  I     t      Cladonia crispata  I     3  I     h     I  t   Cladonia gracilis  II    h  I     t  I     t   I     h  I     t   Cladonia multiformis  I     h        Cladonia phyllophora  I     h  I     h       Cladonia sulphurina  I     h  I     t  I     t      Cladonia uncialis  I     3  I     1       Clintonia uniflora   I     t   I     h  II    2    Coeloglossum viride     I     h    II    h  Coptis trifolia   I     t  I     t      Corallorhiza trifida       I  t   Cornus stolonifera      I  2  I     2   Cystopteris montana       I  t   Delphinium glaucum   I     t  I     t  I     h  I     h  II    h  II    +  Dicranum affine  I     h  I     t     I  h   60APPENDICESAppendix 2Scientica Silvica Extension Series, Number 26, 2000Dicranum fuscescens  I     h  I     h  I     h   I     h    Dicranum polysetum    I     h    I  h   Dicranum scoparium   I     h  I     t   I     h  I     h  II    h  Dicranum spp.      I  h     Distichium capillaceum    I     t      Drosera rotundifolia     I  h     Elliottia pyroliflorus      I  2     Elymus glaucus  I     +    I     h  II    h    Elymus repens    I     t    I  t   Epilobium ciliatum        I  h  Epilobium glaberrimum     I  h     Equisetum arvense   II    +  I     2  II    4  I     h  I     3   Evernia mesomorpha   I     t       Festuca altaica  I     h  I     h  II    +   I     h  I     h   Festuca occidentalis      I  h  I     h   Flavocetraria nivalis   I     h       Frangula purshiana        I  t   Galium bifolium       I  t  II    h  Galium triflorum      II    h  II    +   Gentianella amarella    I     t    I  t   Goodyera oblongifolia   I     h    II    h  I     h   Goodyera repens   II    h  I     h  I     h  II    h  II    h   Gymnocarpium dryopteris      I  h  I     h   Heracleum maximum       I     +  I     h  II    2  Hypogymnia austerodes       I  t   Hypogymnia physodes   I     t       Icmadophila ericetorum   I     t   I     2     Impatiens noli-tangere        II    h  Jungermannia leiantha       I  t   Juniperus communis  I     h        Lathyrus nevadensis   I     h  I     h  I     h  I     h  I     h   Lathyrus ochroleucus    I     h  I     h  II    +  I     +   Leymus innovatus  I     +  I     t  I     h  I     3  I     h  I     2   Lonicera utahensis   I     t       Lupinus arcticus  I     +  I     t  I     h      Luzula parviflora     I  h   I     t   Lycopodium annotinum   II    2  II    1  I     +  I     +  I     4   Lycopodium complanatum   I     h  I     h   I     +    Lycopodium dendroideum   I     t       Lysichiton americanum     I  h     Maianthemum canadense       I  h   Maianthemum stellatum    I     t    I     h  I     t   Maianthemum trifolium     I     +  II    1    II   +  Malaxis brachypoda        I  t   Menziesia ferruginea   I     3       Mnium spinulosum    I     t    I     +    Nephroma arcticum  II    h  I     h       Oryzopsis asperifolia   I     h    I     h    Pentaphylloides floribunda     I     +      Parmelia sulcata   I     t       Parnassia palustris    I     t     II    h  Pedicularis bracteosa    I     t      Pedicularis labradorica   I     t  I     t  I     h     Peltigera malacea   I     h  I     h   I     h  I     t   Peltigera neopolydactyla       I  t   Peltigera praetextata  I     h  I     h  I     t   I     h  I     h  II    h  Peltigera scabrosa   I     +  I     h   I     +  I     h   Petasites sagittatus     I  h    II   +  Phleum alpinum       I  t   Plagiochila aspleniformis     I     h    II    +  Plagiomnium ciliare     I  h   I     t   Vegetation unit Code 110 120 131 132 211 212 220 310Number of plant species 52 129 128 108 107 152 68 16Number of sample plots 5 2534131328 3 1Species Species presence and significance161APPENDICESAppendix 2Mid-seral Black Spruce EcosystemsPlatanthera obtusata   I     t  I     h  I     h  I     h  II    h  II    h  Platanthera orbiculata    I     t  I     h  I     h  I     h   Poa spp.     I     h  I     h   I     h   Poa spp.        I  t   Pohlia spp.    I     t     I  t   Polemonium caeruleum    I     t      Polytrichum commune  I     h  I     +  II    1  II    +   I     4  II    h  Polytrichum juniperinum    I     h    I     t   Polytrichum piliferum   I     h  I     h  I     h     Polytrichum strictum  I     +   I     h      Populus balsamifera   I     h  I     3  I     2  I     2  II    4   Ptilidium pulcherrimum   I     h     I  t   Pulsatilla patens       I  h    Pyrola asarifolia   I     t  I     t   I     h  I     h   Pyrola chlorantha      I  h  I     t   Pyrola elliptica   I     t  I     t  I     h  I     h  I     h   Pyrola minor   I     h     I  h   Ranunculus eschscholtzii        II    h  Rhizomnium pseudopunctatum    I     t  I     h     Rhytidiadelphus triquetrus   I     +   I     h  II    2  I     h   Ribes hudsonianum    I     h  I     h   I     h  II    h  Rubus idaeus    I     +      Rubus parviflorus      I  +  I     3   Salix bebbiana  I     2  I     2  I     +   I     +  I     +   Salix lucida   I     h  I     t    I     +   Salix myrtillifolia  I     1  I     +  I     1  II    3     Salix scouleriana  I     2  I     3  II    3   I     +  I     1   Salix spp.        I  +   Sambucus racemosa       I  t   Sanguisorba canadensis    I     1      Solidago spathulata    I     t  I     h   I     h   Solorina crocea   I     h       Sorbus scopulina    I     t   II    1  I     h   Sphagnum capillifolium    I     +  I     2   I     +  II    3  Sphagnum fuscum    I     3  I     5     Sphagnum magellanicum     I     2     Sphagnum palustre    I     t      Sphagnum rubellum   I     h       Sphagnum squarrosum     I     +     Sphagnum spp.      I     4     Spiraea betulifolia  I     h  I     +    II    2    Spiraea douglasii      I  +    Spiraea pyramidata   I     h     I  t   Splachnum sphaericum   I     h       Stellaria calycantha      I  h    Stereocaulon paschale  II    5  I     h       Stereocaulon tomentosum   I     3  I     h    I     h   Streptopus amplexifolius    I     h      Symphoricarpos albus      I  h    Thalictrum occidentale    I     t   II    1  I     h   Thamnolia vermicularis  I     h  I     t  I     h  I     h     Tiarella trifoliata       I  t   Torreyochloa pallida       I  t   Trientalis europaea      I     h     Trimorpha acris       I  h    Trisetum cernuum   I     t  I     h   I     h  I     h   Trisetum spicatum   I     t       Tritomaria exsectiformis   I     t       Usnea spp.    I     h       Vaccinium caespitosum  I     2  I I     3  I     2  I     h  II    4  I     h   Vaccinium membranaceum  I     4  I I     4  I     1   II    4  I     t  II    h  Vegetation unit Code 110 120 131 132 211 212 220 310Number of plant species 52 129 128 108 107 152 68 16Number of sample plots 5 25 34 13 13 28 3 1Species Species presence and significance162APPENDICESAppendix 2Scientica Silvica Extension Series, Number 26, 2000Vaccinium scoparium  II    2  II    2  I     3  I     h   I     +   Vaccinium uliginosum  I  1  I     h  I     +  II    2     Veratrum viride       I  t   Veronica beccabunga        I  h  Viola canadensis       I  t   Viola orbiculata    I     t      Viola palustris     I  h   I     h  II    h  Viola renifolia      I  h  I     h   Zigadenus elegans      I  h    1. Species presence and significance classes as defined in Table 2.Vegetation unit Code 110 120 131 132 211 212 220 310Number of plant species 52 129 128 108 107 152 68 16Number of sample plots 5 2534131328 3 1Species Species presence and significance163APPENDICESAppendix 3Mid-seral Black Spruce EcosystemsAppendix 3. Plot vegetation table for the Picea mariana - Cladina stellaris plant association, showing species significance in all plots of this plant association. Species are arranged first in order of decreasing presence, then alphabetically.Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes.12345Species Species significance22. Species significance classes as defined in Ta ble  2.Cladina stellaris 6547+Picea mariana 67676Pinus contorta 56776Vaccinium vitis-idaea 43563Pleurozium schreberi 777 9Cladonia ecmocyna 2+ +Hylocomium splendens 686Ledum groenlandicum 3+ +Linnaea borealis ++ +Peltigera membranacea 356Rosa acicularis +2+Arctostaphylos uva-ursi 6+Cladonia gracilis ++Cornus canadensis 3+Dicranella palustris 5+Empetrum nigrum 54Geocaulon lividum +3Nephroma arcticum ++Picea glauca 55Stereocaulon paschale +7Vaccinium scoparium 33Alnus viridis  7Aulacomnium palustre 4Betula nana  3Barbilophozia kunzeana +Cladina arbuscula 4Cladina rangiferina 3Cladonia crispata 5Cladonia multiformis +Cladonia phyllophora +Cladonia sulphurina +Cladonia uncialis 5Dicranum affine +Dicranum fuscescens 1Elymus glaucus 2Epilobium angustifolium +Festuca altaica +Juniperus communis +Leymus innovatus 2Lupinus arcticus 2Mertensia paniculata 2Moneses uniflora +Peltigera praetextata +Polytrichum commune +Polytrichum strictum 2Salix bebbiana 4Salix myrtillifolia 3Salix scouleriana 4Shepherdia canadensis +Spiraea betulifolia +Thamnolia vermicularis +Vaccinium caespitosum 4Vaccinium membranaceum 6Vaccinium uliginosum 364APPENDICESAppendix 4Scientica Silvica Extension Series, Number 26, 2000Appendix 4. Plot vegetation table for the Picea mariana - Vaccinium vitis-idea plant association, showing species significance in all plots of this plant association. Species are arranged first in order of decreasing presence, then alphabetically.Plot number16 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30Species Species significance2Hylocomium splendens   7   7   9   7   +   9   9   9   7   8   7   7   7   7   7   7   5   6   7   5   +   6   6   8  Picea mariana  7   9   7    7   6   7   6   7   9   7   7   6   7   8   7   7   7   7   7   7   6   6   7   7  Pleurozium schreberi  9   7   8   7   7   9   6   7    8   6   7   5   8   8   8   7   6   7   4   9   7   9   9   7  Cornus canadensis  2   3   4   3    5    6   4   3   5   2   3   3   2   5   4   2   3   5   +   +   +   +   2  Pinus contorta  8      6   6    6   6   6   7   7   7    7   7   7   7   5   6   6   7    6   5  Vaccinium vitis-idaea     4    4   2   3   3   +   4   7   4   7   5   6   5   4   1   6   +     +   +  Ledum groenlandicum   2     4   3   +   6   2   +   6    3    6   7   5   5    6   +    3   +   +  Ptilium crista-castrensis   5   +   5    +    5   2   6      5    5   7    8   5   6   9   +   4   6  Linnaea borealis  +   3      2   +   2   +    4      +   2     2    +   +   +   +   +  Peltigera aphthosa    +   4   4   2    4    4    4   4   4   3   4   3    +   5       Petasites frigidus  +   4      +     +    3     +   3   3     +     +   +   +   +  Geocaulon lividum   +   3   6   +   +   3   3   +   +   3             +    +   Cladina stellaris   +     5   +   3   +   5    5    5       7    7   +      Empetrum nigrum     4    3   +   5      2   6     2    1    4   2      +  Orthilia secunda  +    +   +   +     +        +     +    3      +   +   +  Peltigera membranacea   4     3   +     +   3    2   1   3    2   1     4       Rosa acicularis  4   2   3      +    3    4      2       3    2   +    2  Abies lasiocarpa   4   7       3           5   3   6   6    2     6  Vaccinium scoparium  +            2  4   2  6  2      4   +  + Epilobium angustifolium  +    3   +      2     2        +   +  + Shepherdia canadensis  4      +  3   3     3             5    6  3  Arnica cordifolia  +   +  3            +     +      +  Cladonia ecmocyna    +          +  +  +      +  +      Dicranella palustris  +    +         +  2    +   +        Equisetum arvense   +    +       +  +   +       3      Goodyera repens    +  +    +  +         +    +       Lonicera involucrata  +  2              2        +  +   + Lycopodium annotinum  +    6     3     +  1    +          Mertensia paniculata    +      +   +          +     +   + Picea glauca     7     4   6        7       7    6     Vaccinium caespitosum  +  +    6  +           5   6        Vaccinium membranaceum  1               +  6  5  7     4    Viburnum edule    2    2                 +  +  +  + Dicranum scoparium          +    +   +       +  +     Salix bebbiana   4          5  4       1       +  Salix scouleriana     3    6  4      3        4      Cladina arbuscula             5       7   6     +  Dicranum fuscescens    +          +         +     +  Equisetum scirpoides   2    +   +                 +   Festuca altaica  +      +        3  +            Goodyera oblongifolia  +  +  +                    +    Moneses uniflora    +               +   +     +   Peltigera malacea                       +  2  +  + Polytrichum commune       +       +     3  2         Polytrichum piliferum       +        2      +   2      Rubus pubescens  +  +                     +  +   Stereocaulon tomentosum     +         5       4   6      Alnus viridis           5  4          4       Achillea millefolium          +              +  +   Arctostaphylos alpina      +   +   4                 Aster sibiricus   +                     2   +  Cladonia cornuta     +               +   +      Lycopodium complanatum   +       +                 +  Menziesia ferruginea                  7  2   3      Nephroma arcticum                      +    +  2 Pyrola minor     +              +       +   65APPENDICESAppendix 4Mid-seral Black Spruce EcosystemsRubus pedatus      +     +         +         Salix myrtillifolia        4   +               3   Spiraea betulifolia  4  +                     +    Aulacomnium palustre      3   3                   Cladina rangiferina      4                4      Cladonia chlorophaea    +                  +      Cladonia crispata      +              +        Cladonia phyllophora      1  +                    Equisetum sylvaticum      +          +            Galium boreale                       +  +   Mitella nuda          +               +   Oryzopsis asperifolia   2                     +    Peltigera praetextata                      +   +   Peltigera scabrosa         +    4               Populus balsamifera    3                     +   Populus tremuloides    3    2                    Ribes lacustre            +              +  Ribes triste     +     +                  Salix glauca                    3     3   Salix lucida                        +  +  Alnus incana                         +   Antennaria racemosa                       +    Brachythecium spp.     8                       Barbilophozia hatcheri    +                       Calamagrostis canadensis            +               Calamagrostis rubescens                         +  Carex disperma                    +       Cetraria ericetorum                     1      Cladonia cenotea      +                     Cladonia gracilis       +                    Cladonia sulphurina       +                    Cladonia uncialis                   5        Clintonia uniflora                       +    Coptis trifolia          +                 Delphinium glaucum                        +   Dicranum affine      +                     Drepanocladus uncinatus    +                       Equisetum pratense        +                   Evernia mesomorpha           +                Flavocetraria nivalis             1              Hypogymnia physodes        +                   Icmadophila ericetorum             +              Lathyrus nevadensis                       3    Leymus innovatus                +           Listera cordata   +                        Lonicera utahensis                       +    Lupinus arcticus                       +    Lycopodium dendroideum  +                         Maianthemum racemosum                        +    Maianthemum stellatum    +                        Mnium spinulosum     +                       Osmorhiza berteroi    +                        Oxycoccus oxycoccos                  2         Pohlia spp.      +                      Parmelia sulcata        +                   Pedicularis labradorica         +                  Platanthera obtusata                    +       Plot number16 7 8 9 101112131415161718192021222324252627282930Species Species significance266APPENDICESAppendix 4Scientica Silvica Extension Series, Number 26, 2000Ptilidium pulcherrimum             1              Pyrola asarifolia                        +   Pyrola elliptica     +                      Rhytidiadelphus triquetrus    4                       Solorina crocea                 3          Sphagnum rubellum      3                     Sphagnum warnstorfii      3                     Spiraea pyramidata                       2    Splachnum sphaericum           1                Stereocaulon paschale              1             Thamnolia vermicularis               +            Trisetum cernuum                    +       Trisetum spicatum                       +    Tritomaria exsectiformis     +                      Usnea spp.            3                Vaccinium uliginosum              2             1. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes.2. Species significance classes as defined in Ta bl e 2.Plot number16 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30Species Species significance267APPENDICESAppendix 4Mid-seral Black Spruce Ecosystems68APPENDICESAppendix 5Scientica Silvica Extension Series, Number 26, 2000Appendix 5. Plot vegetation table for the Picea mariana - Equisetum sylvaticum: typic plant subassociation, showing species significance in all plots of this plant subassociation. Species are arranged first in order of decreasing presence, then alphabetically.. Plot number131 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64Species Species significance2Picea mariana 7877778987887776677788877766669778Pleurozium schreberi 9776577777676997967788898779877777Hylocomium splendens 678898787899957769787776 865787787Ledum groenlandicum 6744 72 27622+325 3+ 4+245+56+3++Peltigera aphthosa 3+4+352234 +4 + 333333234 5 3544+Vaccinium vitis-idaea 6 2 72+ ++++3 +73 34665+666 42543+Cornus canadensis 6 5422 6+ +575+2552446646442 2Ptilium crista-castrensis 56 4675 56 64322567566 172556Petasites frigidus 32 2 +++3 +414244++234+Rosa acicularis 2++3333 +2+2 +2++++35Pinus contorta 7 5 686 7 6667676576554Equisetum sylvaticum 66 4++222+ + 5+++ +2 3Linnaea borealis + 3 + ++ 3++ +++ +233 22Peltigera membranacea +++2 2 2 + + 2++2+4 2Cladina stellaris + 4 ++ + + 32 ++ + 2 +Lycopodium annotinum + +1+ 3 +3+ 2 + +5Mertensia paniculata 2+ 2 3+ + 3+ 3 + ++Equisetum scirpoides +++5 + + +++ + +Orthilia secunda ++ + ++ + +2Empetrum nigrum 43 2 3 + 23 5 4 +Equisetum pratense +32 + 3Festuca altaica 324++ +++++Picea glauca 646 353 6756Polytrichum commune + 43+ 5 3+2 2+Aulacomnium palustre 5223 3 ++ +2Epilobium angustifolium +545Geocaulon lividum +3 + + 2+ ++ 2Salix scouleriana 42 135243 6Mitella nuda +2+ ++Sphagnum girgensohnii 42 7 4 + 4 2 7Abies lasiocarpa 2645 2 6 3Dicranella palustris 4+ 4 2 + + +Goodyera repens +++Salix glauca 6+3254Vaccinium scoparium 4 +7 2541Vaccinium uliginosum 5+2+ +++Alnus viridis  52 34 2 6Betula nana  5++ +4 4Cinna latifolia ++ ++ + +Salix bebbiana +3 3 43 3Vaccinium caespitosum 3+369APPENDICESAppendix 5Mid-seral Black Spruce EcosystemsVaccinium membranaceum + 5++ +5Cladina arbuscula ++16Ribes triste +3+Rubus pedatus +++Arnica cordifolia ++2 +Carex disperma + ++ +Cladonia ecmocyna Equisetum arvense 6+ +4Larix laricina 66 67Leymus innovatus ++2+Listera cordata +++ +Oxycoccus oxycoccos ++5 2Rubus chamaemorus 4 +Shepherdia canadensis 4+4Viburnum edule 3+ 2Arctostaphylos alpina 4+ 4Betula papyrifera 242Calamagrostis canadensis 4 ++Fragaria virginiana +++Galium boreale ++ +Lonicera involucrata +31. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes.2. Species significance classes as defined in Table 2.Plot number131 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 6470APPENDICESAppendix 6Scientica Silvica Extension Series, Number 26, 2000Appendix 6. Plot vegetation table for the Picea mariana - Equisetum sylvaticum: Larix laricina plant subassociation, showing species significance in all plots of this plant subassociation. Species are arranged first in order of decreasing presence, then alphabetically.Plot number165 66 67 68 69 70 71 72 73 74 75 76 77Species Species significance2Picea mariana 7879757777777Hylocomium splendens 87996776789 7Pleurozium schreberi 6756697577+ 5Vaccinium vitis-idaea 4+644456 254Aulacomnium palustre 234 +23+ +74Ledum groenlandicum 7+6 6 78666 4Cornus canadensis 32 442 2+3 4Equisetum sylvaticum 5 ++4+ 3654Ptilium crista-castrensis +46552 46 3Peltigera aphthosa 23+2 +++Dicranella palustris +132++ +Larix laricina 5556 58Rosa acicularis 25 + ++2Rubus chamaemorus + 73234Rubus pedatus +432+ +Carex disperma ++ 2+4Linnaea borealis 243 ++Maianthemum trifolium  23Petasites frigidus 3+ 3+ 2Calamagrostis canadensis +++ +Cladina stellaris +2Equisetum arvense +54 6Equisetum scirpoides ++ ++Polytrichum commune +3+ +Tomentypnum nitens 626Alnus incana  267Anemone parviflora +++Betula nana  6+2Empetrum nigrum 44 3Epilobium angustifolium ++2Equisetum pratense 2+ 5Geocaulon lividum +++Pinus contorta 357Rhizomnium glabrescens  2+5Salix myrtillifolia +6 4Vaccinium uliginosum 52+Alnus viridis  25Abies lasiocarpa 7+Achillea millefolium ++Arctostaphylos alpina 4+Betula papyrifera 5+Epilobium glaberrimum ++Listera cordata Lycopodium annotinum 3+Orthilia secunda 2+Oxycoccus oxycoccos 6+Peltigera membranacea 2+Picea glauca 74Sphagnum spp.  76Shepherdia canadensis 22Sphagnum fuscum 69Sphagnum girgensohnii 67Sphagnum warnstorfii 63Viburnum edule 5+Actaea rubra +Amblystegium riparium +71APPENDICESAppendix 6Mid-seral Black Spruce EcosystemsAster ciliolatus 2Aster conspicuus +Calliergon stramineum +Cladina arbuscula +Cladonia ecmocyna +Clintonia uniflora 2Coeloglossum viride +Dicranum spp.  +Delphinium glaucum 2Drosera rotundifolia +Elliottia pyroliflorus  5Elymus glaucus 2Equisetum fluviatile +Fragaria virginiana +Galium boreale 3Goodyera repens +Icmadophila ericetorum 5Lathyrus nevadensis +Lathyrus ochroleucus +Leymus innovatus 6Lonicera involucrata 6Luzula parviflora +Lysichiton americanum +Mertensia paniculata 3Mitella nuda +Moneses uniflora +Poa spp.  +Pedicularis labradorica +Petasites sagittatus +Plagiochila aspleniformis +Plagiomnium ciliare +Platanthera obtusata +Platanthera orbiculata +Polytrichum piliferum +Populus balsamifera 5Populus tremuloides 6Pyrola elliptica +Rhizomnium pseudopunctatum 1Rhytidiadelphus triquetrus +Ribes hudsonianum +Ribes lacustre 2Ribes triste +Salix glauca 5Solidago spathulata 2Sphagnum capillifolium 5Sphagnum magellanicum 5Sphagnum squarrosum 4Trientalis europaea  +Thamnolia vermicularis +Vaccinium caespitosum 1Vaccinium scoparium +Viola palustris +1. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes.  2. Species significance classes as defined in Table 2.Plot number165 66 67 68 69 70 71 72 73 74 75 76 77Species Species significance272APPENDICESAppendix 7Scientica Silvica Extension Series, Number 26, 2000Appendix 7. Plot vegetation table for the Picea mariana - Viburnum edule: Sheperdia canadensis plant subassociation, showing species significance in all plots of this plant subassociation. Species are arranged first in order of decreasing presence, then alphabetically.Plot number178 79 80 81 82 83 84 85 86 87 88 89 90Species Species significance2Picea glauca 6 67567657557Pleurozium schreberi +7 5+65777977Rosa acicularis +2+3++++1 414Cornus canadensis ++ 5+24 25235Epilobium angustifolium +++ 3+ 31+5++Hylocomium splendens 3999 8788 77Linnaea borealis +2+3 2+ +++ 1Picea mariana 7676 6 87765Geocaulon lividum + 6 ++ +++4Shepherdia canadensis + 327 4 + 14Viburnum edule + 5+ 4+435Abies lasiocarpa + 5 2 6445Arnica cordifolia +4++ +++Galium boreale + + ++ ++3Petasites frigidus 3 +443+2Pinus contorta 76 5 6668Ptilium crista-castrensis 4+ 5 6527Aster ciliolatus 421+3Fragaria virginiana +++ 32Lonicera involucrata 2+4+Maianthemum racemosum  +3++ 3Osmorhiza berteroi  + + ++ ++Populus tremuloides 79878 7Rubus pubescens ++4+6Elymus glaucus +++Mertensia paniculata ++ 3 ++Mitella nuda Orthilia secunda ++++ +Rhytidiadelphus triquetrus +++25Spiraea betulifolia + ++5+Vaccinium caespitosum +764Vaccinium membranaceum 75 ++4Amelanchier alnifolia 4+3Aster conspicuus 364Clintonia uniflora ++5Festuca occidentalis ++Goodyera oblongifolia + +++Goodyera repens +++ +Lathyrus ochroleucus +3+Sorbus scopulina 4+Thalictrum occidentale +43Actaea rubra 1+4Equisetum sylvaticum +3+Galium triflorum ++ +Peltigera aphthosa 42Ribes lacustre ++ +Alnus incana  33Alnus viridis  63Cladina arbuscula Cladonia ecmocyna ++Cornus stolonifera +5Dicranella palustris Dicranum fuscescens ++Dicranum scoparium ++Drepanocladus uncinatus Equisetum pratense ++73APPENDICESAppendix 7Mid-seral Black Spruce EcosystemsLathyrus nevadensis ++Ledum groenlandicum 4+Lycopodium complanatum 3+Maianthemum stellatum  2+Oryzopsis asperifolia Peltigera membranacea 34Peltigera praetextata ++Platanthera obtusata +2Rubus parviflorus 3+Salix bebbiana 33Salix scouleriana 23Trisetum cernuum ++Vaccinium vitis-idaea 2+Achillea millefolium +Anemone parviflora +Angelica genuflexa +Aquilegia formosa +Arctostaphylos alpina 2Aster sibiricus +Calamagrostis canadensis +Castilleja miniata +Cinna latifolia +Cladina stellaris 5Cladonia gracilis +Delphinium glaucum +Disporum hookeri +Equisetum arvense +Equisetum scirpoides +Festuca altaica +Gymnocarpium dryopteris +Heracleum maximum  4Larix laricina 4Leymus innovatus +Lycopodium annotinum 3Mnium spinulosum  3Pulsatilla patens  +Peltigera malacea +Peltigera scabrosa 4Platanthera orbiculata +Populus balsamifera 5Pyrola asarifolia 2Pyrola chlorantha +Pyrola elliptica +Ribes triste 2Senecio triangularis +Spiraea douglasii 3Stellaria calycantha +Symphoricarpos albus +Trimorpha acris  +Viola renifolia +Zigadenus elegans 21. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. 2. Species significance classes as defined in Ta ble  2.Plot number178 79 80 81 82 83 84 85 86 87 88 89 90Species Species significance274APPENDICESAppendix 8Scientica Silvica Extension Series, Number 26, 2000Appendix 8. Plot vegetation table for the Picea mariana - Viburnum edule: Mitella nuda plant subassociation, showing species significance in all plots of this plant subassociation. Species are arranged first in order of decreasing presence, then alphabetically.Plot number191 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118Species Species significance2Picea mariana 7877887777767667 76666677787Cornus canadensis 44+635448+43465 2+254+36465Hylocomium splendens 9789877777676877 897896 7679Mitella nuda + +++++1+++++243++ 2+++++ 2Pleurozium schreberi 977777678978767 7476 7 786Rosa acicularis 2 4+4++2+ +++222 ++ 33+343 +Linnaea borealis 3 + +26+ +++375 2+ 23++2+2+Petasites frigidus 1 5 233++ +23332+ 2++++45+Picea glauca 8776767666 875 87875777 7Lonicera involucrata 3 5 4 2633++++6+53 + 535+Ptilium crista-castrensis 56467 575477677 467 6 53Mertensia paniculata ++ + 13 +++312+ + +++1 41Viburnum edule +4+ 22+++23 5 ++++4341Epilobium angustifolium +11++++++ 45+++++2Rubus pubescens 1 + 1+ +43+3 +2 443 +2 2Orthilia secunda +++ + ++++++ + ++Ribes lacustre 2 4 ++2+14 +++++3Peltigera aphthosa 3 332 2 +233 2+3 +Pinus contorta 67 4 666++ 8 5 2 5 6Populus tremuloides 5 655 + 5 8 6354 5 7Achillea millefolium + +++++ ++++++Vaccinium vitis-idaea 2254 +6 2Populus balsamifera 4 + 5 564545 76Fragaria virginiana 1+ + + ++2++Equisetum pratense ++ +23 + 24+Equisetum scirpoides 6+ ++Ledum groenlandicum 7 5++2 + 6 + 2Shepherdia canadensis +32 631Abies lasiocarpa 66+555 +Arnica cordifolia 33+ + +++ +Aster sibiricus 2 +++Galium boreale + ++++++ +Geocaulon lividum ++ 2Goodyera repens ++ ++ + + ++Actaea rubra ++ 23 +Calamagrostis canadensis 2+ 2 + + 2 +Galium triflorum 2+ 3Listera cordata ++++ +75APPENDICESAppendix 8Mid-seral Black Spruce EcosystemsPeltigera membranacea 222+ 22 +Ribes triste 22 + + 2Rubus pedatus 7+2 3 + + +Alnus incana  4+623Aster ciliolatus 1++ + ++Delphinium glaucum ++ ++++Equisetum sylvaticum +++++2Moneses uniflora ++Osmorhiza berteroi  2Platanthera obtusata ++++ ++Alnus viridis  5+4 42Aulacomnium palustre +4 +3+Betula papyrifera 4233Dicranella palustris 3+Polytrichum commune +463 7Pyrola asarifolia 3++ ++Pyrola minor +++ +Vaccinium scoparium 213 + 4Cladonia ecmocyna +++ +Equisetum arvense 7+++Lathyrus nevadensis +1 +Lathyrus ochroleucus 42 22Lycopodium annotinum 67+ +Platanthera orbiculata ++ + +Pyrola elliptica + +++Solidago spathulata ++Trisetum cernuum + +++Viola palustris +Amelanchier alnifolia ++ 3Carex disperma 4+4Cladina stellaris 3++Dicranum scoparium 3+ +Disporum hookeri +2+Heracleum maximum  222Leymus innovatus 6+ 4Rhytidiadelphus triquetrus 3+Salix bebbiana 43 3Salix scouleriana 444Sorbus scopulina ++ 2Aster conspicuus Cinna latifolia ++Cladina arbuscula Cornus stolonifera 63Festuca altaica + +Festuca occidentalis ++Plot number191 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118Species Species significance276APPENDICESAppendix 8Scientica Silvica Extension Series, Number 26, 2000Goodyera oblongifolia ++Gymnocarpium dryopteris 32Larix laricina 77Maianthemum racemosum  +5Maianthemum canadense Oxycoccus oxycoccos +4Poa spp.  ++Peltigera praetextata ++Peltigera scabrosa +2Ribes hudsonianum 2 1Salix spp.  Salix glauca 6 2Thalictrum occidentale 2 3Vaccinium caespitosum 2 2Viola renifolia ++Agrostis mertensii +Aralia nudicaulis 2Aster modestus +Betula nana  2Bryum spp.  +Carex spp.  4Calliergon cordifolium 4Calypso bulbosa +Campylium stellatum 1Carex concinna +Carex rossii 3Cladonia crispata +Cladonia gracilis +Corallorhiza trifida +Cystopteris montana +Dicranum affine 3Dicranum polysetum 2Drepanocladus uncinatus +Elymus repens +Empetrum nigrum 2Equisetum fluviatile +Frangula purshiana  +Galium bifolium +Gentianella amarella +Hypogymnia austerodes +Jungermannia leiantha +Luzula parviflora +Maianthemum stellatum  +Malaxis brachypoda  +Poa spp.  +Plot number191 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118Species Species significance277APPENDICESAppendix 8Mid-seral Black Spruce EcosystemsPohlia spp.  +Peltigera malacea +Peltigera neopolydactyla +Phleum alpinum +Plagiomnium ciliare +Polytrichum juniperinum +Ptilidium pulcherrimum +Pyrola chlorantha +Rhizomnium glabrescens  +Rubus chamaemorus +Rubus parviflorus 7Salix lucida 5Sambucus racemosa +Sphagnum capillifolium 4Sphagnum girgensohnii +Sphagnum warnstorfii 5Spiraea pyramidata +Stereocaulon tomentosum 1Tiarella trifoliata +Tomentypnum nitens 1Torreyochloa pallida +Vaccinium membranaceum +Veratrum viride +Viola canadensis +1. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. 2.* Species significance classes as defined in Table 2.Plot number191 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118Species Species significance278APPENDICESAppendix 9Scientica Silvica Extension Series, Number 26, 2000Appendix 9. Plot vegetation table for the Picea glauca & mariana - Equisetum pratense plant association, showing species significance in all plots of this plant association. Species are arranged first in order of decreasing presence, then alphabetically.Plot number1119 120 121Species Speciessignificance2Angelica genuflexa + + 4Equisetum pratense 7 5 6Hylocomium splendens + 7 7Ledum groenlandicum + 3 5Lonicera involucrata 3 4 5Mertensia paniculata 1 4 3Mitella nuda + + 2Petasites frigidus + + 5Picea mariana 8 7 7Pleurozium schreberi 7 6 6Aulacomnium palustre 5 6Carex disperma 6 3Disporum hookeri 1 +Equisetum scirpoides + 2Geum macrophyllum 3 4Listera cordata + +Moneses uniflora + +Orthilia secunda + +Oxycoccus oxycoccos + +Picea glauca 6 7Ptilium crista-castrensis 8 6Rhizomnium glabrescens  5 +Ribes triste + +Rosa acicularis 3 5Rubus pubescens 2 3Salix glauca 4 3Senecio triangularis + +Sphagnum girgensohnii 7 +Alnus incana  5Anemone parviflora +Arnica cordifolia +Aster ciliolatus +Calamagrostis canadensis 7Calliergon stramineum +Carex rossii +Cladina stellaris +Cladonia ecmocyna +Coeloglossum viride +Cornus canadensis 6Delphinium glaucum 2Dicranum scoparium +Epilobium angustifolium 2Epilobium ciliatum +Equisetum sylvaticum 6Galium bifolium +Heracleum maximum  3Impatiens noli-tangere +Larix laricina +Linnaea borealis 3Maianthemum trifolium  2Osmorhiza berteroi  2Parnassia palustris +Peltigera aphthosa 3Peltigera praetextata +79APPENDICESAppendix 9Mid-seral Black Spruce EcosystemsPetasites sagittatus 2Plagiochila aspleniformis 1Platanthera obtusata +Polytrichum commune +Ranunculus eschscholtzii +Ribes hudsonianum +Ribes lacustre 2Rubus pedatus 2Sphagnum capillifolium 4Sphagnum warnstorfii +Vaccinium membranaceum +Vaccinium vitis-idaea +Veronica beccabunga +Viola palustris +1. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. 2. Species significance classes as defined in Ta ble  2.Plot number1119 120 121Species Speciessignificance280APPENDICESAppendix 10Scientica Silvica Extension Series, Number 26, 2000Appendix 10. Selected environmental characteristics for plots of the SbPl - Lichens site association derived from the Picea mariana - Cladina stellaris plant association (110).Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Table 7.12345Zonal unit BWBSdk1BWBSdk2BWBSdk2BWBSmw1BWBSdk1Soil moisture regime* 2/MD 2/MD 2/MD 2/MD 2/MDSoil nutrient regime* VP P P VP VPElevation (m) 870 860 840 1000 1020Slope gradient (%) 10 5 24 40 2Aspect* ESNSNForest floor thickness (cm) 10 7 6 6 5Generalized textural class* L L L S LPotential rooting depth (cm) 60 60 60 60 25Water table depth (cm) N/A N/A N/A N/A N/ASoil drainage* W M W R RSoil Great Group R HFP HFP HFP HFPStand age (years@bh) 64 142 54 71 151Site index (m) 9.9 7.3 N/D 9.6 9.1Tree layer cover (%) 20 40 70 50 25Shrub layer cover (%) 11 1 5 48 5Herb layer cover (%) 2 1 0 1 1Moss layer cover (%) 70 97 38 55 8381APPENDICESAppendix 11Mid-seral Black Spruce EcosystemsAppendix 11. Selected environmental characteristics for plots of the SbPl - Moss site association derived from the Picea mariana - Vaccinium vitis idaea plant association (120).Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Table 7.6 7 8 9 10 11 12 13 14 15 16 17 18Zonal unit SBSdkSBSdw3BWBSdk1BWBSdk1BWBSdk1BWBSdk1BWBSdk1BWBSdk1BWBSdk2BWBSdk2BWBSmw2BWBSmw2BWBSmw2Soil moisture regime* 3/SD 4/SD 3/SD 4/SD 4/SD 4/SD 5/F&M 4/SD 4/SD 4/SD 4/SD 4/SD 4/SDSoil nutrient regie* PPPPMPPPPPPPPElevation (m) 890 890 1000 990 805 810 840 850 830 750 400 1100 1190Slope gradient (%) 0 0 27 6 31 24 16 27 0 11 0 11 16Aspect* FFSEESSSFSFEWForest floor thickness (cm) 5 8 13 16 30 4 14 11 11 10 6 12 11Generalized textural class* L L S S L L O L S L L L LPotential rooting depth (cm) 40 50 60 60 60 30 55 40 50 35 65 60 60Water table depth (cm) N/A N/A N/A N/A N/A N/A N/A N/A 70 N/A N/A N/A N/ASoil drainage* W W W M M M I M I W M I MSoil Great Group HFP HFP EB EB EB EB H HFP DYB HFP HFP HFP GLStand age (years@bh) N/D 95 N/D N/D 43 37 62 82 129 135 72 59 81Site index (m) N/D 8.6 N/D N/D N/D N/D 8.3 13.5 N/D 10.1 8.8 7.8 N/DTree layer cover (%) 70 72 57 30 50 31 33 36 45 83 50 60 35Shrub layer cover (%) 7 6 3 2 12 6 15 29 6 0 30 24 19Herb layer cover (%) 23571511331712Mos layer cover (%) 807890957581929796957 7045Plot number 19 20 21 22 23 24 25 26 27 28 29 30Zonal unit BWBSmw2BWBSmw1BWBSwk1BWBSwk1BWBSwk1BWBSwk1BWBSwk1BWBSdk1SBSdw3BWBSdk1BWBSdk1BWBSdk1Soil moisture regime* 4/SD 4/SD 3/SD 3/SD 3/SD 4/SD 3/SD 3/SD 4/SD 4/SD 4/SD 4/SDSoil nutrient regime* P P VP P P P P VP P VP VP PElevation (m) 1100 1000 1100 1130 1080 1050 1025 1015 785 895 905 895Slope gradient (%) 51 5 11 60 16 82 0 30 10 23 14 60Aspect* SSWNNNFNNNENForest floor thickness (cm) 14 8 12 11 4 10 11 11 7 19 11 7Generalized textural class* L L S L S L L S L L L LPotential rooting depth (cm) 60 60 70 70 60 50 50 15 15 50 10 80Water table depth (cm) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/ASoil drainage* I M W W R W R R M W W RSoil Great Group GL HFP HFP HFP HFP HFP HFP HFP EB M HFP HFPStand age (years@bh) 134 84 N/D 136 63 72 160 149 109 93 80 176Site index (m) 7.3 9.0 N/D N/D 12.7 N/D 7.9 8.9 8.6 10.5 13.2 10.0Tree layer cover (%) 55 90 50 60 41 77 50 40 36 15 45 45Shrub layer cover (%) 25 18 66 40 39 2 26 0.8 13 6 13 2Herb layer cover () 225413603111Moss layer cover (%) 99 91 100 92 80 90 94 98 90 96 98 10082APPENDICESAppendix 12Scientica Silvica Extension Series, Number 26, 2000Appendix 12. Selected environmental characteristics for plots of the Sb - Wood Horsetail. Sb site association derived from the Picea mariana - Equisetum sylvaticum: typic plant subassociation (131).Plot  number131 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47Zonal unit BWBSdk1BWBSdk1BWBSdk1BWBSdk2BWBSmw2BWBSdk2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSdk1SBSmk1BWBSmw2BWBSdk1Soil moisture regime* 6/VM 6/VM 6/VM 5/F&M 5/F&M 6/VM 6/VM 6/VM 6/VM 6/VM 6/VM 5/F&M 6/VM 5/F&M 5/F&M 6/VM 5/F&MSoil nutrient regime* VP VP P VP P P VP VP VP VP VP VP VP P P VP PElevation (m) 920 910 800 870 660 530 630 640 540 540 440 450 1020 880 930 1170 860Slope gradient (%) 10 5 0 0 16 0 10 10 0 0 10 0 0 13 8 27 11Aspect* WSFFSFWWFFWFFNSWSForest floor thickness (cm) 14 12 23 12 9 10 14 9 15 15 14 16 12 13 10 16 11Genralized textural cas*OOOOCOOOOOOOOOSCLLPotential rooting depth (cm) 50 35 60 40 60 90 45 40 50 40 60 50 45 70 40 40 60Water table depth (cm) 55 35 70 42 20 70 45 20 50 40 45 N/A 50 N/A N/A 40 N/ASoil drainage* P P I P I P P P P P P I P M W P MSoil Great Group M M M M G M F M F M M F M M HFP GL DYBStand age (years@bh) 185 151 118 99 135 141 130 137 122 71 134 72 48 87 103 86 71Site index (m) 4.7 5.2 8.1 8.7 9.5 6.7 8.6 N/D N/D 8.7 8.1 7.9 N/D 9.5 10.3 7.5 11.5Tre layer cover (%) 2060354069507496773158504026407921Shrub layer cover (%) 23 23 19 16 31 37 2 0 3 44 16 1 17 11 10 25 9Herb layer cover (%) 11 22 16 6 5 8 1 1 2 13 1 0 0 3 13 21 7Mos layer cover (%) 10 9693828099819991989195949590839583APPENDICESAppendix 12Mid-seral Black Spruce EcosystemsPlot number 4849505152535455565758596061626364Zonal unit BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSmw1BWBSmw2SBSmk1BWBSmw2BWBSwk1BWBSmw2BWBSdk1BWBSdk1BWBSmw2Soil moisture regime* 6/VM 5/F&M 5/F&M 5/F&M 6/VM 5/F&M 5/F&M 6/VM 5/F&M 5/F&M 5/F&M 6/VM 5/F&M 6/VM 5/F&M 5/F&M 6/VMSoil nutrient regime* PPPPPPMPPPPPMVPPPVPElevation (m) 390 1100 1070 1115 1120 1130 840 830 980 1010 930 1170 1080 1120 800 760 350Slope gradient (%) 0 11 31 31 16 36 11 0 16 11 8 5 29 16 20 11 0Aspect* F E W S E W S F W N E N N N W W FForest floor thickness (cm) 15 13 14 14 12 13 11 15 12 8 18 12 15 15 8 11 12Genralized textural cas*CLLLCLLLLLLSLLLLLLPotential rooting depth (cm) 55 60 40 50 40 60 30 30 48 46 15 60 45 60 60 40 60Water table depth (cm) 45 44 40 55 40 N/A N/A 15 N/A 45 N/A 48 45 45 N/A N/A 43Soil drainage* P I P I P I I P I P W I M P M I PSoil Great Group G GL GL GL GL GL GL GL GL GL HFP GL GBL GL EB GL GLStand age (years@bh) 77 62 61 128 124 117 99 92 57 53 92 100 N/D 122 118 72 106Site index (m) 11.0 9.8 7.7 7.0 6.1 7.2 10.7 9.0 10.9 N/D 10.5 N/D N/D N/D 8.1 11.1 10.1Tre layer cover (%) 404040.57070608045803025458075653380Shrub layer cover (%) 5 9 5 11 14 14 1 36 28 17 13 22 21 10 22 10 6Herb layer cover (%) 0 2 13 7 6 3 5 11 13 5 33 4 4 1 2 9 2Moss layer cover (%) 97 79 98 97 99 91 92 76 95 52 86 81 97 82 87 97 1001. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Ta ble  7.84APPENDICESAppendix 13Scientica Silvica Extension Series, Number 26, 2000Appendix 13. Selected environmental characteristics for plots of the Sb - Tamarack site association derived from the Picea mariana - Equisetum sylvaticum: Larix laricina plant subassociation (132).Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Ta ble  7.65 66 67 68 69 70 71 72 73 74 75 76 77Zonal unit BWBSmw2BWBSmw2BWBSmw1BWBSmw2BWBSwk1BWBSmw2BWBSmw2BWBSmw1BWBSmw2BWBSmw2BWBSdk1BWBSmw2BWBSmw2Soil moisture regime* 7/W 7/W 6/VM 7/W 7/W 7/W 7/W 7/W 7/W 7/W 7/W 7/W 7/WSoil nutrient regime* P VP P P VP P VP VP VP VP P VP VPElevation (m) 385 400 940 350 1120 1160 380 990 360 520 910 440 440Slope gradient (%) 0 0 16 0 0 5 0 0 0 0 11 0 0Aspect* FFWFFWFFFFWFFForest floor thickness (cm) 13 16 20 14 12 12 29 30 14 19 12 20 20Generalized textural class* C O O L L L O O O O O O OPotential rooting depth (cm) 55 35 60 30 50 30 60 50 60 40 50 70 50Water table depth (cm) 25 25 20 15 10 25 20 20 10 30 50 10 5Soil drainage* PPPPPVVVVPVVPSoil Great Group G F M GL GBL GL M H F F H F FStand age (years@bh) 73 73 129 108 151 83 109 N/D 147 124 149 74 69Site index (m) 11.6 8.8 6.9 10.9 N/D 9.3 9.0 N/D N/D N/D N/D 11.0 N/DTre layer cover (%) 356050865528354545512 2575Shrub layer cover (%) 25 0 5412392350802711181233Herb layer cover () 7115482642151737Moss layer cover (%) 100 94 90 100 32 93 91 100 100 70 93 50 4885APPENDICESAppendix 14Mid-seral Black Spruce EcosystemsAppendix 14. Selected environmental characteristics for plots of the SbSw - Soopalallie site association derived from the Picea glauca & mariana - Viburnum edule: Sheperdia canadensis plant subassociation (211). Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Table 7.78 79 80 81 82 83 84 85 86 87 88 89 90Zonal unit SBSdw3BWBSdk2BWBSdk2BWBSdk1SBS mk1SBS mk1BWBSmw2SBS mk1SBSdw3SBSmk1SBSdw3SBSdw3SBSdw3Soil moisture regime* 4/SD 4/SD 4/SD 4/SD 3/SD 3/SD 4/SD 4/SD 4/SD 4/SD 4/SD 3/SD 4/SDSoil nutrient regime* R M M P P M M M R M R R RElevation (m) 730 840 680 910 955 850 390 840 830 800 740 880 850Slope gradient (%) 2 10 0 11 0 0 10 32 5 18 8 10 5Aspect* NWFSFFESENSFNForest floor thickness (cm) 9 8 5 13 2 6 9 40 16 7 6 10 16Genralized textural cas*CLLSLLLLLLLLLPotential rooting depth (cm) 30 60 70 70 45 60 55 60 40 15 60 60Water table depth (cm) N/A N/A 70 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/ASoil drainage* I M M M R W M W W M M W MSoil Great Group GL GL R EB DYB DYB DYB HR EB DYB GL DYB EBStand age (years@bh) 98 N/D 44 N/D N/D N/D 108 N/D 100 79 94 98 96Site index (m) 12.8 N/D N/D N/D N/D N/D 13.9 N/D 10.4 12.2 8.1 11.2 11.9Tre layer cover (%) 55655345827590727570487289Shrub layer cover (%) 6 5 0 3 26 51 0 5 8 4 8 12 26Herb layer cover (%) 6 1 2 19 23 11 3 3 12 6 24 6 16Mos layer cover (%) 1 979596 0 117041818571836586APPENDICESAppendix 15Scientica Silvica Extension Series, Number 26, 2000Appendix 15. Selected environmental characteristics for plots of the SbSw - Common Mitrewort site association derived from the Picea glauca & mariana - Viburnum edule; Mitella nuda plant subassociation (212). Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Ta bl e 7.91 92 93 94 95 96 97 98 99 100 101 102 103 104Zonal unit SBSdw3BWBSdk2BWBSmw1BWBSmw2BWBSmw1BWBSmw2BWBSmw2BWBSmw2BWBSmw2SBSmk1BWBSdk1BWBSdk1BWBSdk1BWBSmw1Soil moisture regime* 6/VM 5/F&M 5/F&M 5/F&M 5/F&M 5/F&M 5/F&M 5/F&M 5/F&M 5/F&M 6/VM 5/F&M 5/F&M 5/F&MSoil nutrient regime* MMMMRVRMMRRPMMMElevation (m) 890 750 1000 390 1030 970 830 830 840 790 780 970 1030 940Slope gradient (%) 5 5 16 5 20 0 5 0 0 3 15 17 23 31Aspect* S S N W N F S F F N N N W WForest flor thicknes (cm)10 9 1312132017141 1614141211Generalized textural class* O L L C L L L L L L O O L LPotential roting depth (cm)4010 404070506050402530354060Water table depth (cm) 38 N/A N/A 45 70 N/A N/A 35 30 75 40 60 N/A N/ASoil drainage* PWIIMIIPIIIIIISoil Great Group H HFP GL G GBL GBL GL GL GL GBL FO H GL GLStand age (years@bh) 94 134 84 69 157 54 60 114 100 126 105 102 98 84Site index (m) 10.1 14.0 11.8 13.0 7.8 N/D 13.8 10.7 12.3 9.9 9.7 10.2 9.3 10.4Tree layer cover (%) 43 75 75 80 83 88 55 60 53 60 40 30 50 70Shrub layer cover (%) 15 1 8 0 65 5 4 28 11 6 1 6 2 5Herb layer cover (%) 38 4 5 0 23 2 13 36 4 55 2 9 3 7Moss layer cover (%) 87 95 97 98 96 94 64 65 92 75 98 90 100 100Plot number 105 106 107 108 109 110 111 112 113 114 115 116 117 118Zonal unit BWBSmw2BWBSmw1SBSmk1SBSmk1BWBSmw2BWBSmw2BWBSmw2BWBSmw2BWBSdk1BWBSmw2BWBSmw1SBSdkBWBSmw1BWBSmw2Soil moisture regime* 5/F&M 6/VM 5/F&M 5/F&M 6/VM 5/F&M 6/VM 6/VM 5/F&M 6/VM 5/F&M 5/F&M 5/F&M 6/VMSoil nutrient regime* MMRMMMMMMMRMVRVRElevation (m) 830 1020 940 765 500 340 450 490 970 450 950 890 995 800Slope gradient (%) 0 16 15 0 0 0 0 0 7 10 5 0 11 0Aspect* FNSFFFFFWENFWFForest floor thickness (cm) 15 16 12 11 9 15 12 10 14 15 11 12 15 23Generalized textural class* L L S L C C C C L C L O L LPotential rooting depth (cm) 60 46 30 20 60 30 60 60 25 60 60 40 60 60Water table depth (cm) 45 46 N/A N/A 25 N/A 20 10 N/A 30 N/A N/A 50 23Soil drainage* I I W I I I P P M P I I I ISoil Great Group GBL GBL DYB GBL G DYB GBL G GBL GBL GL H GL GBLStand age (years@bh) 115 153 N/D 75 76 117 62 77 99 64 83 N/D 85 N/DSite index (m) 10.6 9.1 N/D 9.9 12.6 10.5 14.0 13.8 9.2 N/D 14.0 N/D 11.6 N/DTree layer cover (%) 71 65 77 45 73 58 77 65 30 78 55 70 90 60Shrub layer cover (%) 43 27 68 4 0 0 6 6 12 1 17 8 14 1Herb layer cover (%) 17 7 7 11 1 1 7 4 2 2 17 11 17 11Mos layer cover (%) 7 81 0 927591917030214732758187APPENDICESAppendix 16Mid-seral Black Spruce EcosystemsAppendix 16. Selected environmental characteristics for plots of the SbSw - Meadow Horsetail site association derived from the Picea glauca & mariana - Equisetum pratense plant association (220). Plot number11. Plot numbers have been simplified in this report. See Appendix 17 for original plot codes. * Abbrevations as defined in Table 7.119 120 121Zonal unit SBSdw3BWBSwk1BWBSmw1Soil moisture regime* 7/W 7/W 7/WSoil nutrient regime* M R MElevation (m) 840 1020 990Slope gradient (%) 0 0 0Aspect* F F FForest floor thickness (cm) 11 9 24Generalized textural class* O O OPotential rooting depth (cm) 50 40 70Water table depth (cm) 35 30 35Soil drainage* V P VSoil Great Group H H HStand age (years@bh) N/D 172 144Site index (m) N/D 6.3 N/DTree layer cover (%) 60 50 50Shrub layer cover (%) 10 6 23Herb layer cover (%) 5 10 62Moss layer cover (%) 40 93 7288APPENDICESAppendix 17Scientica Silvica Extension Series, Number 26, 2000Appendix 17. Converstion of the plot numbers used in this report to the plot codes used in the original data set (SbKK.MDB) on file with the British Columbia Ministry of Forests, Research Branch, in the VENUS data base.plot numberplot codeplot numberplot codeplot numberplot code197-0794297-1328398-1172 97-095 43 97-153 84 97-1383 97-112 44 98-140 85 98-1184 97-184 45 98-136 86 97-0225 98-123 46 97-157 87 98-1126 97-001 47 97-078 88 98-1317 97-014 48 97-145 89 97-0068 97-046 49 97-150 90 97-0169 97-053 50 97-151 91 97-01310 97-062 51 97-154 92 97-11911 97-064 52 97-156 93 97-17812 97-075 53 97-161 94 97-14313 97-085 54 97-166 95 97-18614 97-114 55 97-169 96 97-16315 97-118 56 97-179 97 97-16516 97-148 57 97-152 98 97-16817 97-149 58 98-137 99 97-17018 97-160 59 97-159 100 98-11319 97-162 60 97-187 101 98-12620 97-176 61 97-155 102 98-12721 97-180 62 97-070 103 98-12822 97-182 63 97-087 104 97-17123 97-183 64 97-135 105 97-16724 97-188 65 97-144 106 97-18525 97-189 66 97-146 107 98-12126 98-124 67 97-172 108 98-11627 98-133 68 97-136 109 97-14028 98-139 69 97-181 110 97-13729 98-141 70 97-158 111 97-13030 98-142 71 97-142 112 97-13931 97-039 72 97-175 113 98-12532 97-044 73 97-147 114 97-12933 97-071 74 97-128 115 97-17334 97-115 75 97-035 116 97-00235 97-141 76 97-134 117 97-17736 97-122 77 97-133 118 97-16437 97-123 78 98-132 119 98-11938 97-124 79 97-113 120 97-19039 97-125 80 97-092 121 97-17440 97-126 81 97-043 122 97-01241 97-131 82 98-122

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