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Decay following pruning of Balsam fir in the Maritime Provinces of Canada Van Sickle, Gordon Allan 1969

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DECAY FOLLOWING PRUNING OF BALSAM FIR IN THE MARITIME PROVINCES OF CANADA by GORDON ALLAN VAN SICKLE B.S.F., The University of B r i t i s h Columbia, 1965 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN FORESTRY Faculty of Forestry We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA October, 1968 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and Study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . It i s understood t h a t copying or p u b l i c a t i o n of t h i s thes.i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department of The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada Date r~)rf~^J^ ^ , S; / i ABSTRACT As management of forests and parks intensifies, pruning of conifers becomes more common. Thus understanding the role of wounds as possible entry courts for decay fungi i s v i t a l . In order to study some aspects of t h i s , three natural stands, one i n New Brunswick and two i n Nova Scotia, which had been pruned k to 7 years ea r l i e r by industrial or displaced workers, were examined. Five pruned and two unpruned balsam f i r (Abies balsamea (L.) M i l l . ) trees from each stand were dissected; cultural isolations were taken from 207 knots where pruning had caused l i t t l e or no apparent damage to the bole, and from 169 blazes resulting from less careful prunings. A l l 15 pruned trees, ranging i n age from 23 to k2 years, had decay attributable to pruning which averaged 1.7$ of the stem volume. This incidence and volume of decay exceeds that recorded i n unpruned trees 40 to 60 years old i n New Brunswick. Axe blazes were the major entry court for decay-causing fungis basidiomycetes were associated with 12% of the blazes and with 5% of the more carefully pruned knots. Neither stem nor butt decay was found In the unpruned trees. In a further study, 7 branches on each of 30 balsam f i r trees near Fredericton, N. B. were experimentally axe pruned; some carefully, some carelessly; both during tree dormancy and during wet and dry periods i i of active growth. Thirty additional branches were saw pruned. At periods of 2 to 3 weeks, 5 to 7 months and 17 to 19 months after pruning, cultures were made i n the f i e l d from 70 of the pruning wounds. Within 2 weeks of the l a t t e r period, the trees were dissected, measured and further cultures were made i n the laboratory from the same 70 wounds. Eighteen months after pruning, 28 of 30 trees had decay averaging 3.9$ of stem volume and basidiomycetes were isolated from 22 (31$) of 70 wounds. In the controls butt decay only occurred i n h> of 10 trees. These studies show: ( l ) that blazes into sapwood (careless pruning) were more frequently infected than those where l i t t l e or no sapwood was exposed; (2) the incidence of infection was least i n branches pruned during the dry period and about equal for those pruned i n the wet-active and dormant periods; and (3) the successlonal pattern began with imperfect fungi and bacteria, and terminated with decay fungi. i i i CONTENTS Page Abstract i L i s t of Tables v L i s t of Illustrations v i i Acknowledgments i x Vita Introduction 1 Literature Review 3 Incidence of Decay After Pruning 3 Season of Pruning 5 Experimental and Survey Methods 7 Experimental Pruning, Acadia Forest Experiment Station 7 Study Area 7 (a) Dormant Pruning 8 (b) Active-wet Pruning 10 (c) Active-dry Pruning 12 Tree Measurements and Fruit Body Survey 12 Field Culturing 1^  Dissection of Pruned trees 15 Survey of Pruned Balsam F i r and White Spruce 17 Cull Study 17 Study Areas 18 Results 20 Experimental Pruning of Balsam F i r 20 Field Culturing 21 Dissection of Pruned Trees and Laboratory Culturing 25 Fruit Body Survey 33 Cull Survey of Pruned Trees 33 Balsam F i r 33 White Spruce 37 i v Discussion References Appendix I . I I . I I I . IV. Page 38 45 Botanical and common names f o r tree species 49 referred t o i n t e x t . Botanical names f o r fungi referred to i n t e x t . 50 Schedule of pruning and c u l t u r i n g f o r 33 balsam 52 f i r trees at Acadia Forest Experiment S t a t i o n , New Brunswick. Related data f o r a l l wounds or knots from which 53 basidiomycetes were i s o l a t e d i n 30 pruned balsam f i r at Acadia Forest Experiment S t a t i o n . LIST OF TABLES Average branch diameter and wound size following pruning of 7 branches on each of 30 balsam f i r trees. Weather during 5 day period centered about day of pruning. Proportion of pruned balsam f i r branches from which basidiomycetes were isolated i n f i e l d cultures. Analysis of variance for incidence of basidiomycetes following careful and careless axe pruning of balsam f i r at three different times and from three different times of is o l a t i o n . Proportion of basidiomycetes isolated during f i e l d and laboratory culturing of the same pruned balsam f i r branches. Number of pruning wounds, A-G, with basidiomycetes during f i e l d and laboratory culturing and pro-portion of decay associated with each fungus. Incidence of each basidiomycete isolated during f i e l d and laboratory culturing from branches pruned at three different times. Incidence of balsam f i r pruning wounds infected with basidiomycetes according to wound size. Fruit bodies of wood-decay fungi collected from standing dead trees and slash near the site of the pruning study at Acadia Forest Experiment Station. Data on 5 balsam f i r trees i n each of 3 pruned stands. Number of knots and wounds from which basxdiomycetes were isolated i n 5 balsam f i r trees i n each of 3 pruned stands. Frequency of isol a t i o n of different organ-isms i n apparently normal and discolored wood associated with pruned branches of balsam f i r . V l l LIST OF ILLUSTRATIONS Figure Page Typical wounds produced by pruning balsam f i r branches. A. carelessly axe pruned, D. carefully axe pruned, G. saw pruned. Basal section of pruned branches showing 11 location of iso l a t i o n attempts. Pruned balsam f i r , trees 2 and 3« Unpruned 13 branches to 10 f t were clipped to 6 In. from the bole. A natural 37-year-old balsam f i r stand on 18 Crowdis Mountain pruned and thinned i n 1963 and being managed for Christmas trees and pulpwood. Corticium laeve f r u i t body on a wound resulting 21 from branch pruning of this balsam f i r tree less than 1-j years earlier. Cultural results at different times following 23 pruning of balsam f i r at Acadia Forest Experiment Station. Radial stem section of knots carefully axe 25 pruned during dormancy ( l e f t ) and growth (right). Corticium laeve and Stereum purpureum were isolated from the branch on the right and l e f t respectively. 8 Radial stem section of knot carefully saw pruned from which Stereum purpureum and basidiomycete 1 were isolated. 26 Transverse sections of tree no. 30 taken every foot from ground le v e l to 10 f t . This 36-year-old balsam f i r tree contained 17.5l'° of i t s volume as firm decay. S i r i c i d l a r v a l galleries are evident (arrow) and the location of wounds A, C and S are noted. Aureobasidium pullulans was isolated from C 2 weeks after pruning, Peniophora sp. from E 5 months after pruning and Corticium laeve from A 17 months after pruning. Amylostereum c h a i l l e t i i was isolated i n the laboratory from wound A. Radial stem section of knot and wound from which Amylostereum c h a i l l e t i i was Isolated and s i r i c i d larvae taken. Evidence of wound on balsam f i r h years after pruning (left.) "Radial section of same wound from which Stereum sanguinolentum was isolated (right). i x ACKNOWLEDGMENTS W, R. Newell assisted with f i e l d work, culturing and compilation of results, Dr. M. K. Nobles ident i f i e d cultures of Stereum purpureum and Corticium laeve, L. P. Magasi confirmed or corrected the i d e n t i f i -cation of the major groups of the basidiomycetes, and Dr. R. S. Forbes offered valued c r i t i c i s m of the manuscript. The late Dr. J. E. Bier, Faculty of Forestry, University of B r i t i s h Columbia, guided the early stages of this study and gave encouragement and inspiration. Dr. A. Kozak suggested the analysis of variance which was used. Gordon Allan Van Sickle October 15, 1968 DECAY FOLLOWING PRUNING OF BALSAM FIR IN THE MARITIME PROVINCES OF CANADA INTRODUCTION In the Maritime Provinces numerous pruning projects have been i n i t i a t e d u t i l i z i n g unemployed or displaced workers. The Nova Scotia Department of Lands and Forests i s interested i n managing vast areas of the Cape Breton plateau as a Christmas tree-pulpwood operation. Numerous 1/ areas are suited to th i s style of management for balsam f i r , a native species, reproduces well on a variety of s i t e s . Stands can then be pruned and thinned to 2500 to 3000 stems per acre, approximately 6ofo of which can l a t e r be cut for Christmas trees and the balance l e f t f o r pulpwood. In the Maritimes, growing of Christmas trees i s a small, but important industry which augments the annual income of many farmers. Annual export from the Region i s about 4.0 m i l l i o n trees of which 2.5 m i l l i o n are from Nova Scotia, nearly 1.5 m i l l i o n from New Brunswick and less than 0.5 m i l l i o n For botanical names of this and other trees referred to, see Appendix I. 2 from Prince Edward Island (McLeod, 1968). Regionally, balsam f i r i s one of the most Important sources of pulpwood. The removal of the lower whorls of branches by pruning f a c i l i t a t e s easier movement i n the stand, encourages formation of f u l l e r - f o l i a g e d trees, increases l a t e r a l twig development, and provides a good bottom whorl of branches. Most areas, however, w i l l not y i e l d sizable quantities of well-shaped Christmas trees i n d e f i n i t e l y and consideration should be given to a future y i e l d of pulpwood (McLeod, 1968). R. Mason (personal communication), contractor f o r pruning and thinning operations on Crowdis Mountain, Cape Breton Island, N.S., observed that nearly a l l the trees pruned i n 1962 and cut i n 196^ f o r the Christmas market had some butt rot, thus raising the question of c u l l i n the remaining trees. Accordingly, a preliminary survey was made during September, 1965 of f i v e randomly selected pruned balsam f i r trees (Van Sickle, 1966). A l l contained noticeable firm decay. Basidiomycetes were isolated from 15 of 39 wounds where sapwood was exposed at the time of pruning and from k of 7k knots after careful pruning which exposed only the cut surface of the • branch. Numerous problems evident i n t h i s study could not be overcome unless one was present at the time of pruning. I t was not known, for example, i f the association of a fungus with branch stubs resulted from several single-branch infections, or i f i t was an extension of heart rot established through broken tops or dead leaders. Uncertainty also existed whether decay entered through l i v i n g or dead branches and before or after the branches were pruned. Questions of who did the pruning, using what tools, at what time of year and which year could seldom be answered as early 3 pru.rd.ngs were not well documented and were usually winter works programs rather than forest operations. Consequently, i t was decided to exper-imentally prune a small number of trees to follow closely the Infection process and to determine i f incidence of decay-causing fungi i s altered by more careful pruning or by timing the operation to coincide with certain weather conditions. LITERATURE REVIEW Incidence of Decay After Pruning That benefits from pruning might be reduced or n u l l i f i e d by heart rot infections entering through pruning wounds has seldom been questioned. Andrews (195*0 concluded that pruning protects ponderosa 2/ pine from decay by Polyporus anceps by eliminating recently dead branches, the p r i n c i p a l i n f e c t i o n avenues. Similarly, Baxter (196?) reported that small, much-weathered branch stubs provided infection courts for Fomes p i n i and suggested that early pruning would have reduced the probability of infection. Andrews (195*+) f e l t knots exposed by pruning were unimportant as entrance points for disease. Davidson and Redmond (1957) found branch stubs the most important infection courts for trunk decaying fungi i n i ; r T o 7 n o m e n c l a t u r e for t h i s and other fungi included i n this paper, see Appendix I I . white spruce, while i n red spruce, wounds were as important as branch stubs. Childs and Wright (1956) evaluated the practice of clubbing and sawing-off of dead and l i v i n g branches of young Douglas f i r and concluded that heart-rotting fungi often gain entrance through pruning wounds, but the average extent of decay was s l i g h t . Others working on a variety of coniferous hosts who agree that proper pruning caused no defects of any p r a c t i c a l importance include Harris (1966), Herman (1963), Bauger and Orlund (1962), Finnis (1953) and Hawley and Clapp (1935). In B r i t a i n , decay following pruning i s attributed to pruning of large (2 i n . + diameter) branches or to careless work, especially brashing (branch removal to f a c i l i t a t e access to stands), which leaves torn bark or long ragged stubs (Henman, 1963). Uncontrolled lopping of trees i n India, resulted i n i n j u r i e s through which fungi entered (Bagch.ee and Bakshi, 1950). In central New York State, Risley and Silverborg (1958) found Stereum sanguinolentum causing extensive heart rot associated with wounds after branches, averaging 0.5 to 1 i n . diameter, had been pruned. Five years after the Norway spruce trees were axe pruned, f r u i t bodies were abundant both on branch stubs and exposed sagwood. The resulting decay progressed rapidly and i n some trees both heartwood and sapwood were decayed resulting i n death. Sleeth (1938) and Spaulding and MacAloney (1935) also reported that S. sanguinolentum infected wounds and formed f r u i t bodies when 2 to 5 i n . white pine branches were pruned. They concluded that young infected trees would be worthless before reaching a merchantable size and they cited a Swedish report of S. sanguinolentum entering blazes on Norway spruce and i n less than two years causing decay that extended an average of 2 m from the wound. 5 Toole (1961) reported rot associated with 29$ of the 1696 dead branches sampled i n pruned hardwood trees, but S k i l l i n g (1958) found no indication that a r t i f i c i a l pruning encouraged development of decay i n sugar maple and white elm. The work outlined above involves studies i n a l l parts of the world on a variety of species, i n different seasons, emphasizing attacks by different fungi under different climates, using different tools and for different reasons; hence, the d i f f i c u l t y i n obtaining a concensus. None of these studies, however, concerned balsam f i r , the wood of which i s completely lacking i n natural d u r a b i l i t y to decay (Bakuzis and Hansen, 1965). Considerable information, however, i s available regarding natural wounds on balsam f i r as entry courts f o r decay fungi. Early workers (Basham, Mook and Davidson, 1953; Spaulding and Hansboroiagh, 1944; Kaufert, 1935 and McGalium, 1928) considered dead branches and stubs the most important infection courts of the destructive heart rot fungus, S. sanguinolentum, but t h i s has not been v e r i f i e d . In a r t i f i c i a l i n f e c t i o n experiments, dead branches unlike l i v i n g branches did not serve as points of entry f o r S. sanguinolentum (Davidson and Etheridge, 1963). Their further work showed this fungus becomes established i n heartwood sol e l y by way of i n j u r i e s to l i v i n g stems and branches. Since pruning wounds are a form of injury, they could easily be infection courts. Season of Pruning Ho agreement exists on the best season for pruning. Ralston and Lemien (1956) and Hawley and Clapp (1935) preferred dormant season 6 pruning, but c h i e f l y f o r convenience i n the work schedule. Roth (1939) stated wounds made during the growing season heal more rapidly than those made at other seasons of the year, but care i s needed to avoid excessive bark stripping. Childs and Wright (1956) found much higher fungal inf e c t i o n from spring pruning than from autumn pruning. Henman (1963) reported European studies based on the incidence of fungal damge, which showed the only safe time for pruning to be the dormant season. On the other hand, Roth (1939) reported the work of Swarbrick and Priestley i n England who found "wounds made between A p r i l and September rapidly blocked the entry of decay; wounds made during September and October were blocked only p a r t i a l l y and those made from October to May seldom were blocked u n t i l the following spring." Similarly, Davidson and Etheridge (1963) found i n f e c t i o n highest i n trees damaged i n the winter and lowest i n those injured i n mid-summer, Bauger and Orlund (1962), however, reporting on pruning performed i n the autumn, winter and l a t e spring, found no season to be less suitable than the others. Similarly, Lohrey (1963) found no s i g n i f -icant differences i n the time required for healing of wounds made throughout the year. Etheridge (1965), the f i r s t to consider the requirements of the infecting organisms, determined that spores of S. sanguinolentum were produced from mid-April to mid-November, but infection of balsam f i r occurred only during periods of rain and when mean d a i l y temperatures were between 38 to 60 F. Sus c e p t i b i l i t y of summer produced i n j u r i e s f e l l rapidly and i r r e v e r s i b l y Zk hr aft e r exposure (which agrees with Bakuzis 7 and Hansen, 1965» that aging of wounds increases resistance to infec t i o n ) , but winter produced i n j u r i e s were s t i l l susceptible when thawing commenced early i n A p r i l . Unfortunately, similar data are lacking for other fungal organisms or hosts. EXPERIMENTAL Al© SURVEY METHODS Experimental Pruning, Acadia Forest Experiment Station Study Area In March, 1966 a detailed pruning study of balsam f i r was started at the Acadia Forest Experiment Station, 13 miles east of Fredericton, New Brunswick. The study area l i e s within the Eastern Lowlands Section (A. 3) of the Acadian Forest Region (Rowe, 1959) which i s "characterized by softwood stands of black spruce, red spruce and balsam f i r or mixed woods i n which these species are associated with white pine, red maple, sugar maple, yellow birch and white birch. The gently undulating plain i s underlain by flat-bedded sandstones, shales and conglomerates. The surface t i l l s are mostly of a clay loam or sandy loam texture and podzolic i n s o i l p r o f i l e development." Much of t h i s area i s i n Canada Land Inventory class 5 (31 to 50 f t mai). The stand chosen f o r study had an understorF " of f a i r l y open-grown balsam f i r with l i v i n g crowns within two feet of the ground. The average age of the balsam f i r at ground l e v e l was 39 years and the s i t e index was 25 at 50 years. Many of the overstory hardwoods were girdled during winter of 196l. 8 T h i r t y - f i v e balsam f i r trees of good form and free of noticeable insect or disease damage were numerically tagged. On each tree, between 2 and 8 feet above the ground, seven branches were selected and let t e r e d A to G inclusive. Generally only one branch per whorl was selected and the l e t t e r sequence and compass bearing of the f i r s t chosen branch on each tree was varied systematically so branches of the same notation were not always on the same side of the tree or at the same height. The trees were then randomly assigned to three groups of ten, one tree was designated as an extra i n each group and two were l e f t to be used as and i f needed. Ten additional trees were designated as controls and received no treatment. On March 10, 1966, a Stevenson weather screen containing a maximum-minimum thermometer and Fuess hygrothermograph was established i n the stand and maintained u n t i l September 19, 1966. (a) Dormant Pruning On March 23, 1966, while the trees were s t i l l dormant, a l l 35 branches lettered A and 35 lettered B were pruned using a hand axe; A branches were carelessly pruned i n such a manner that the bark and outer sapwood were wounded (Fig. l ) , B branches were pruned as carefully as possible without leaving a protruding branch stub or s i g n i f i c a n t l y wounding the bole (Table 1). The status ( l i v i n g or dead) and the diameter of each pruned branch were recorded and basal 1-ft sections were labelled and taken to the laboratory. Within 2k hr each was s p l i t through i t s center and three small pieces of wood aseptically removed (Fig, 2 ) and placed on Zfo malt agar slants to establish the presence or absence of fungi i n the branches at time of pruning. Unpruned branches i n and near the whorls c o n f i n i n g A and B were clipped k to 6 i n . from the bole using hand pruning shears to reduce the Figure 1. Typical wounds produced by pruning balsam f i r branches. A. c a r e l e s s l y axe pruned, D. c a r e f u l l y axe pruned, G. saw pruned. p o s s i b i l i t y of decay entry through these branches, but s t i l l provide a microclimate about the pruned branches s i m i l a r to that around a f u l l y pruned t r e e . During the f i v e days, March 21 to 25, centered about the day of dormant pruning, the mean d a i l y temperature ranged from J6 to 4^-0 F averaging 38 F, and measurable p r e c i p i t a t i o n (.01 i n . or more) was recorded on three 1/ days (Table 2 ) . Balsam f i r buds i n t h i s area normally f l u s h about May 11 . Forbes, R. S. (Unpubl. data, 196?) A phenological survey of the Maritime Provinces based on shoot growth measurements on balsam f i r . 10 Table 1. Average branch diameter and wound size following pruning of 7 branches on each of 30 balsam f i r trees. Branch and date of pruning Avg. pruned branch diameter (n=30) (in.) AVK. size of pruning wound. Length Width (in.) (in.) Area » ( i n . 2 ) March 23 (dormant) A B 0.45 0.45 3-3 0.9 1.2 0.7 o.5 b July 4 (active-dry) C D 0.41 Q.42 3.7 1.2 1.3 0.9 2.4*; 0 . 9 b June 9 (active-wet) E F G 0.42 0.38 0.41 3.9 1.2 0.7 1.2 0.8 0.7 2< 0.4 b Area = L . W Area = H + Wj 2 = TTr2 (b) Active-wet Pruning On June 9, 1966 following a period of moderate temperatures and high humidities and no change forecasted, branches lettered E were carelessly axe pruned, those lettered F, were car e f u l l y axe pruned, and those lettered G (Fig. were pruned using a hand saw to undercut and then cut from above to prevent tearing the bark when the branch f e l l . As i n the dormant pruning, other branches near those pruned were clipped and basal sections of branches E, F and G were taken to the laboratory and cultured. During the f i v e days June 7 to 11, measurable precipitation was recorded on three days; for 76 hr the rela t i v e humidity exceeded 80$, averaging 78$, and the mean d a i l y temperature ranged from 46 to 63 F, averaging 54 F (Table 2 ) . Based on l a t e r a l shoot elongation, approximately 11 Figure 2. Basal section of pruned branches showing l o c a t i o n of i s o l a t i o n attempts. Table 2. Weather during 5 day period centred about day of pruning. 5 day mean No. hr Type and date Temperature (F) r e l a t i v e r e l a t i v e No. days of pruning 5 day mean range humidity humidity ppt. >.01 i n . ' (j) > 80$ Dormant 38 36-40 83 86 3 March 23 Active-wet 54 46-63 78 76 3 June 9 Active-dry 64 61-69 63 42 0 Ju l y 4 12 50% of the growth was completed by t h i s date . (c) Active-dry Pruning On July 4, 1966 following a period of high temperatures and low humidities, and no change forecasted, branches lettered C were carelessly axe pruned and those "lettered D were car e f u l l y axe pruned (Fig. l ) . As before, sections of the pruned branches were cultured and the remaining branches from ground l e v e l to 8 to 10 f t were clipped 4 to 6 i n . from the bole (Fig. 3) . During the f i v e days, July 2 to 6, no measurable pre c i p i t a t i o n was recorded, and for 42 hr the r e l a t i v e humidity exceeded 80$, averaging 63$ and the mean d a i l y temperature ranged from 61 to 69 F, averaging 64 F (Table 2 ) . July 4 coincided with the f i v e year average date for completion of shoot elongation f or balsam f i r . Tree Measurements and F r u i t Body Survey As an indication of the inoculuim present for possible infection, samples of f r u i t bodies found on l i v i n g or dead standing or f a l l e n trees were collected June 23, 1966. These were dried and the i d e n t i f i e d specimens are deposited i n the Ideological Herbarium at the Forest Research Laboratory, Fredericton, N.B. On July 6, 1966 after a l l trees had been pruned the location of each was mapped and record made oft diameter at breast height, the aspect 17 Forbes. (Unpubl. data, 196?) Ibid. 13 Figure 3« Pruned balsam f i r , trees 2 and 3« Unpruned branches to 10 f t were clipped k to 6 i n . from the bole. of each pruned branch with respect to cardinal compass points, the length and width to the nearest 0.1 i n . and the height above ground level to nearest foot of each wound. The 30 pruned and 10 control trees averaged 39 years at ground lev e l , 3«1 i n . dbh, 21.^ f t i n height, and 1.1 f t per year i n terminal 14 growth for the past 6 years. The l i v e crowns (top of pruning) averaged 8.3 f t i n height. Seven branches were pruned from each of the 30 trees and 202 of the 210 t o t a l (96.2$) had green foliage when pruned. The diameters of pruned branches averaged 0.42 i n . (s = 0.12), ranging from 0.2 to 0.8 i n . Field Culturing Two to three weeks after each period of pruning, is o l a t i o n attempts were made from the wounds on 10 randomly selected trees (Appendix I I I ) . Each wound was surface s t e r i l i z e d with 70$ alcohol and allowed to dry before three small wood chips (one next to knot and one each above and below the knot) were removed and placed on 2$ malt extract agar slants. Isolations were to be made using a s t e r i l i z e d increment hammer (Hubert, 1954), but because positioning the hammer and the variable size of the wood chip was a problem, narrow carpenter chisels were used. On October 17»1966, 5 to 7 months after the branches were pruned, 10 wounds of each type, A to G inclusive, were surface s t e r i l i z e d and isolations made as before, Similarly, on October 17, 1967, 17 to 19 months after pruning, the last 10 wounds of each type were cultured i n the same manner. The presence on the wound surfaces of f r u i t bodies or insect emergence holes was noted at this time. After 20 to 27 days under laboratory conditions of l i g h t and temperature, a l l tubes were macroscopically examined and classified as containing! no growth (negative) bacteria, imperfect fungi (Fungi Imperfect!) or a mixture of two or more organisms. Cultures suspected of being 15 basidiomycetes were examined microscopically and when necessary sub-cultured to obtain pure cultures. Cultures of imperfect fungi were l a t e r examined microscopically and c l a s s i f i e d to form family and occasionally to form genus according to Barnett (i960). Basidiomycetes with d i s t i n c t i v e characteristics (Stereum sanguinolentum and Amylostereum c h a i l l e t i i ) were frequently i d e n t i f i e d using mounts prepared from the tube, but a l l others and the unidentified cultures were transferred to P e t r i plates and examined weekly for six weeks according to methods outlined by Nobles (1965). Basidiomycetes were recognized by the presence of clamp connections, or i n those that are simple septate the combination of f i b e r hyphae, chlamydospores, etc, I t i s generally accepted that basidiomycetes are the major wood decay fungi; with one exception (white spongy heart rot of sugar maple caused by Hypoxylon deustum), non-basidiomycetes are believed incapable of causing decay i n l i v i n g trees (Basham and Morawski, 1964; Wagner and Davidson, 1954). The assumption was made that basidiomycetes isolated from stained wood were capable of causing decay and the basidiomycetes isolated and i d e n t i f i e d i n t h i s study are known i n the l i t e r a t u r e to f u l f i l Koch's postulates. Dissection of Pruned Trees Within 15 days of the l a s t f i e l d culturing, the 35 pruned and 10 control trees were f e l l e d at ground l e v e l and cut into 1-ft bolts to the l i v i n g crown, or u n t i l no decay was noted on the cross section. I f the stem diameter was not then less than 3 i n . , the tree was cut into 4-ft bolts u n t i l this l i m i t was reached, the inside bark diameter of the transverse face of each section was measured to the nearest 0.1 i n , as were the diameters of a l l defects on these faces. Wood noticeably softer than normal, healthy 16 heartwood was c l a s s i f i e d as unfirm decay. I f the reduction i n hardness was very s l i g h t , I t was c l a s s i f i e d as firm, decay. Tree volumes to l i v i n g crowns and the volumes of firm and unfirm decay were calculated using Smalian's 6/ formula . Butt decays were traced to t h e i r uppermost l i m i t and t h e i r volumes calculated separately. Stump age was determined by ring count or i n the few cases of hollow centres, the age at stump was estimated by adding to the number of rings countable, the average number of years required by 10 other trees i n the plot to reach a radius corresponding to the radius of the rot column. Total tree height was also recorded as were any defects overlooked when the trees were selected. A l l bolts containing pruning wounds from which i s o l a t i o n s were attempted 3 to 15 days e a r l i e r were taken to the laboratory and dissected using a bandsaw. Each wound was sectioned v e r t i c a l l y through the knot (branch base embedded i n the wood of a tree trunk) and examined f o r evidence of decay or discoloration. Within 24 hr of dissection, three i s o l a t i o n attempts were made from the margin of the discolored zone, or from the 1966 growth ring i f no discoloration was evident. Small s u p e r f i c i a l chips were removed with a flamed scalpel then a smaller chip was cut from the sapwood and transferred aseptically to a malt agar slant. Several knots of clipped, unpruned branches on each tree were also dissected and examined. Bolt sections were stored at 35 F for 20 to 25 days at which time the cultures 17 ^T±JSL L Volume i n f t = 2 where 2 B = area of large end of bolt, f t b = area of small end of bolt, f t L = length of bolt i n f t 17 were examined and c l a s s i f i e d . A l l knots that yielded negative cultures or imperfect fungi, as well as several with basidiomycetes, were recultured as checks. Survey of Pruned Balsam F i r and White Spruce Cul l Study Three commercially thinned and pruned areas with f a i r l y complete records were located i n 1967: a balsam fir-white spruce stand i n the Green River watershed, RestigouchsCounty, N.B., and two balsam f i r stands on Crowdis Mountain, Cape Breton Island, N.S. (Fig. k). In each area f i v e pruned and two unpruned control balsam f i r trees were randomly selected and cut at ground l e v e l . At the Green River s i t e f i v e pruned and two control white spruce trees were included. A l l trees were scaled and the percentage decay was estimated as previously outlined. The boles were transferred to the laboratory and stored at 35 F and within 1 to 7 weeks dissected using a bandsaw to r a d i a l l y section wounds and embedded branches. Record was made of branch diameter, status ( l i v i n g or dead) as judged by a macroscopic examination of growth rings and presence of bark inclusions, height of branch above base i n 1-ft classes, wound size, and v i s i b l e signs of decay or discoloration. Within Zk hr of dissection, three i s o l a t i o n attempts were made from the exposed faces as previously outlined. Cultures were stored and c l a s s i f i e d as before except only basidiomycetes were retained f o r i d e n t i f i c a t i o n . 18 Figure 4. A natural 37-year-old balsam f i r stand on Crowd!s Mountain pruned and thinned i n 1963 and being managed for Christmas trees and pulpwood, Study Areas Block W3 i n the Green River watershed i s crown land containing approximately 15 acres that was thinned and brashed, i n August, I960 by woods employees of Fraser Companies Limited. The area has a moderate slope 19 with a northeastern aspect. Both balsam f i r and white spruce averaged 35 years of age at ground l e v e l . Rowe (1959) c l a s s i f i e d this area as Gaspe section (B. 2) of the Boreal Forest Region; characterized by "plateau-like highlands... which are a northeastward extension of the Appalachian Mountain system. The major forest cover types are dominated by conifers, although mixed conifer-hardwood stands are not uncommon. Balsam f i r , black spruce and white spruce, often i n combination with white birch form the characteristic cover types. Thin podzol p r o f i l e s with rather heavy, but poorly-structured B horizons, are common i n the well-drained position." Crowdis Mountain, Cape Breton Island, N.S, i s l a r g e l y crown land currently leased and clear cut by Bowaters Mersey Paper Company Limited, but i n 1969 i t w i l l be transferred to Nova Scotia Pulp Limited. Much of the area has heavy natural regeneration of balsam f i r with 6,000 to 10,000 plus stems per acre. About 1,000 acres have been thinned and pruned with axes, saws and a pruning machette to approximately 2,500 to 3i000 stems per acre. The Cape Breton plateau section (A .6) of the Acadian Forest Region as c l a s s i f i e d by Rowe (1959) "shows marked s i m i l a r i t i e s to the Gaspe section. Balsam f i r , white spruce, black spruce and white birch are the chief species, with the f i r dominating. Shallow s o i l s p r e v a i l and p r o f i l e development under the cool-moist climatic conditions i s to humus podzols, gleysols, and peats, according to drainage." Two locations on the plateau were sampled; one was thinned and pruned by R. Mason, Sp r i n g h i l l , N.S. during June, 1962, the other during September, I963. The average age of balsam f i r was 37 years and 24 years, respectively. Both areas had a s i t e index of 25 at 50 years and would be i n Canada Land Inventory class 5 (31 to 50 f t mai). RESULTS Experimental Pruning of Balsam F i r Three balsam f i r trees were deleted from the sample and replaced by predetermined alternates. Tree 28 was injured by a f a l l i n g tree during winter 1966, a mycelial fan of A r m i l l a r i a mellea was found at the base of tree 5 and tree Ik was cultured out of sequence. The remaining 10 trees i n each group had not been v i s i b l y injured to influence the effects of pruning. Butt decay was present i n l / 3 of the pruned trees, but ended i n the f i r s t 1-ft bolt and was not i n contact with decay attributed to pruning. Cultures from the butts of three trees yielded A. mellea and one yielded 3. sanguinolentum. Four control trees also contained measurable butt decay, but the average percent of volume decayed i n the Ik trees was only 0.24% Macroscopically similar f r u i t bodies were observed i n October, 1967 on wounds on seven trees; one sporophore (Fig. 5) was i d e n t i f i e d as Corticium laeve. 21 Field Culturing Of 420 isolations made at the time of pruning from the basal end of pruned branches, 402 (95.7$) were s t e r i l e , 16 (3.8$) yielded a variety of imperfect fungi, 3 contained bacteria and 1 from a dead branch, ho. 10 B contained an unidentified nodose septate basidiomycete. As the cultures made i n October, 1967 from 10 B yielded only bacteria an 22 an imperfect, i t was f e l t that the decay fungus f a i l e d to enter the bole and there was no need to delete t h i s branch from the sample. Of 210 isolations made during each period, I.e. 2 to 3 weeks, 5 to 7 months, and 17 to 19 months after pruning; 1.4$, 6.6% and 19.5$. respectively contained basidiomycetes, 10.9$. 18.1$ and 21.9$. respectively yielded moniliaceous imperfects, and 53.4$, 47.6$ and 22.4$, respectively yielded dematiaceous imperfects (Fig. 6 ) . Bacteria were present i n 7.6$, 37.6$ and 68.6$ of the cultures. Less than 10$ of cultures made at any one time contained Penicillum spp. Because a single tube frequently contained as many as three different organisms, totals often exceed 100$, In the t o t a l 630 f i e l d cultures made, Phialophora spp. (8,2$) were the most common moniliaceous fungi, Aureobasidium pullulans type IV (11,4$) and A. pullulans type III (7.8$) were the most common dematiaceous fungi. Types I I I and IV are as designated i n the culture c o l l e c t i o n of the Faculty of Forestry, University of B r i t i s h Columbia, and are similar to those described by Barnett (i960) and Funk ( i960). I t i s possible that the l a t t e r , t y p i f i e d by thick-walled resting spores, i s simply a resting stage of the former i n which blastospores are abundant. The resin-inhabiting fungus Retinocyclus abietis occurred i n 4.0$ of the cultures. Less frequently occurring imperfect fungi included Fusarium, Cephalosporium, Alternaria, Torula, Graphium and Trichocladium. Representative cultures have been retained i n the stock culture c o l l e c t i o n at the Forest Research Laboratory, Fredericton, N.B. One or more basidiomycetes were obtained i n f i e l d cultures from 34 of the 210 wounds examined (Table 3) . The proportion of branches con-taining basidiomycetes increased from .05 at »2 to 3 weeks to .31 at 17 to 19 months after pruning. Most decay-causing fungi were isolated from 23 Figure 6. Cultural results at different times following pruning of balsam f i r at Acadia Forest Experiment Station,, branches pruned during active growth i n the wet period (.23), followed closely by those pruned during dormancy (.18) and were least (.08) for branches pruned during growth i n the dry period (Fig. 7) . Carelessly pruned branches consistently had a higher proportion (.24) of basidiomycetes than carefully pruned branches (.09). An analysis of variance (Keeping p. 219-227, 1962), indicated significant differences at the 5$ l e v e l of 24 Table 3. Proportion of pruned balsam f i r branches from which basidiomycetes were i s o l a t e d i n f i e l d c u l t u r e s . Type and time of pruning Avg. time of i s o l a t i o n (excluding) sawn) Dormancy Active-dry Active-wet Type of i s o l a t i o n Care- Care-l e s s f u l l y Care- Care-l e s s f u l l y Care- Care-l e s s f u l l y Sawn (Pruning plus) 2-3 weeks o a 0 0 .1 0 .05 5-7 months .1 .3 .1 0 .3 o .1 .13 17-19 months *6 .1 e 2 » 1 .8 .1 .3 .31 Avg. f o r type of pruning .23 .13 .10 .07 .40 .07 .13 Avg. f o r time of pruning .18 .08 .23 -a proportion of 10 branches examined from which basidiomycetes were i s o l a t e d . p r o b a b i l i t y between the occurrence of basidiomycete i n c a r e f u l l y and care-l e s s l y axe-pruned branches and among the times of c u l t u r a l i s o l a t i o n (Table 4 ) . Saw pruning ( F i g . 8 ) , however, was not s i g n i f i c a n t l y d i f f e r e n t at the 5% l e v e l to c a r e f u l axe pruning with respect t o incidence of decay-causing f u n g i , 25 Figure 7° Radial stem section of-knots carefully axe pruned during dormancy ( l e f t ) and growth (right). Corticium laeve and Stereum purpureum were i s o -lated from the branch on the right and l e f t respectively. Dissection of Pruned Trees and Laboratory Culturing Measurable decay (Fig. 9) attributable to pruning occurred i n 28 of 30 pruned trees. Butt decay, only, occurred i n 4 of 10 unpruned control trees. The average volume decayed i n the 28 trees was .02 f t ^ (3«9$ of the stem volume) only 17 to 19 months after 7 branches on each tree were pruned. There was considerable variation (range .02$ to 18.9$) i n the amount of decay i n trees, largely because of the action of different fungi. Most was firm decay with only 2 trees having a trace of unfirm decay. One or more basidiomycetes were isolated during f i e l d culturing from 22 (73$) of the pruned trees. Laboratory cultures made from the same branches as, and 26 Figure 8. Radial stem section of knot carefully saw pruned from which Stereum purpureum and basidiomycete 1 were isolated. immediately following the October, 1967 f i e l d cultures provided similar relationships, but a higher overall proportion of basidiomycetes (Table 5). During dissection of tree 17, branch E, numerous l a r v a l galleries were noted and one small larva with a single anal spine was identified as Sirex juvencus L., the woodwasp from which S t i l l w e l l (1966) isolated A. c h a i l l e t i i . The adult woodwasp i s attracted to and oviposits i n weakened and newly dead balsam f i r ( S t i l l w e l l , 1966) and apparently was attracted to the pruning wounds. Other larvae found (Family Melandryidae and Ichneumonidae) were those commonly parasitic on the woodwasp. Larval galleries were found i n a l l but 1 of the 9 trees from which A. c h a i l l e t i i was isolated and of 16 knots or wounds from which this fungus was isolated, 27 Table 4. Analysis of variance f o r incidence of basidiomycetes f o l l o w i n g c a r e f u l and careless axe prunin. g of balsam f i r at three d i f f e r e n t times and from three d i f f e r e n t times of i s o l a t i o n . Source of V a r i a t i o n DF MS F F .05 Time of pruning (C) 2 .0351 I .63 N.S.a 4.10 Careful vs careless pruning-CA VS A-J_) 1 .1089 5.04 * 4.96 Time of i s o l a t i o n (T) 2 .1116 5.17 * 4.10 A * T 2 ,0906 4.19 * 4.10 ErrorD 10 .0216 Total 17 N.S, not s i g n i f i c a n t . * s i g n i f i c a n t at 0,05 p r o b a b i l i t y l e v e l n o n - s i g n i f i c a n t C * A and C * T Interactions pooled to the error term, i n s e c t g a l l e r i e s were found i n 8 ( F i g , 10). Had each branch been completely d i s s e c t e d , g a l l e r i e s might have been found i n more branches, but sometimes the entry court could have been a d i f f e r e n t wound some distance from the point of i s o l a t i o n . Basidiomycetes were i s o l a t e d from a l l but 4 of the 30 pruned trees during f i e l d and lab o r a t o r y c u l t u r i n g . When the amount of decay present i n each tree was proportioned according to the t o t a l number of cultures of each basidiomycete obtained from that t r e e , i t was estimated that A. c h a i l l e t i i was associated with approximately 46$ of the decay 28 Figure 9 . Transverse sections of tree no. 3 0 taken every foot from ground l e v e l to 10 f t . This 36 - y e a r - o l d balsam f i r tree contained 17.5$ of i t s volume as f irm decay. S i r i c i d l a r v a l gal ler ies are evident (arrow) and the location of wounds A, C and E are noted. Aureobasidium pallulans was isolated from C 2 weeks after pruning, Peniophora sp. from E 5 months after pruning and Corticium laeve from A 17 months after pruning. Amylostereum c h a i l l e t i i was isolated i n the laboratory from wound A. 29 Table 5. Proportion of basidiomycetes isolated during f i e l d and laboratory culturing of the same pruned balsam f i r branches. Type and time of pruning Dormancy Active-dry Active-wet Avg. time Type of isola t i o n Care- Care-less f u l l y Care- Care-less f u l l y Care- Care- Sawn less f u l l y of i s o l a t i o n (excluding sawn) Fie l d a .6b .1 • 2 .1 .8 .1 .3 .31 Laboratory .9 .2 A A .7 .2 A Al Avg« of lab cultures for type of pruning .55 AO A5 a f i e l d culture results repeated from Table 3. proportion of 10 branches examined from which basidiomycetes were isolated. Figure 10. Radial stem section of knot and wound from which Amylostereum c h a i l l e t i i was isolated and s i r c i d larvae taken. 30 present after pruning. C. laeve caused 21$ of the decay followed by purpureum with 9$» Peniophora sp. 5$i and S. sanguinolentum 4$ (Table 6). The balance was attributed to several unidentified basidiomycetes. With but two exceptions, laboratory recultures yielded the same organisms as did the o r i g i n a l laboratory i s o l a t i o n attempts. Cultures from 41 branches that had previously yielded bacteria and/or imperfect fungi again yielded bacteria and/or imperfects. Similarly, cultures from 4 branches again yielded basidiomycetes indicating retention of v i a b i l i t y Table 6. Number of pruning wounds, A-G, with basidiomycetes during f i e l d and laboratory culturing and proportion of decay associated with each fungus No. of knots or wounds which yielded basidiomycetes Decay amounta Laboratory associated Basidiomycete F i e l d cultures at cultures with fungus 2-3 5-7 17-19 17-19 ($) weeks months months months White rots Amylostereum c h a i l l e t i i 1 1 - 14 46 Corticium laeve - 1 9 7 21 Peniophora sp. 1 - 1 2 5 Stereum sanguinolentum - 1 - 3 4 Stereum purpureum - - 4 6 9 basidiomycete 1 — — 5 — 1 Brown rots basidiomycete 2 1 2 - - 7 basidiomycete 3 - 1 - _ 2 unidentified^ 3 — 3 3 5 Total r 9 c 22° 32 c 100 bamt. of decay per tree proportioned by no. of cultures of each basidiomycet includes groups 4-8 inclusive and mixed cultures of 70 knots and wounds examined 31 a f t e r 3 weeks cold storage. Only one branch from which bacteria were o r i g i n a l l y isolated yielded a basidiomycete, C. laeve, i n the recultures. One branch from which S_. purpureum was o r i g i n a l l y isolated yielded instead two b a c t e r i a l and one s t e r i l e culture. However, the same basidiomycete was again isolated from each of these exceptions after a further 3 weeks storage. A. c h a i l l e t i i was mainly isolated from branches pruned during the dry period of growth and during dormancy (Table 7) . This might be expected Table 7« Incidence of each basidiomycete isolated during f i e l d and laboratory culturing from branches pruned at three d i f f e r e n t times. Time of pruning Basidiomycete Dormancy Active-dry Active-wet No. % No. % No. % Amylostereum c h a i l l e t i i 5 7.8 1° 15.6 1 1.6 Dorticium laeve 7 10.9 - - 5 7.8 1 1.6 4 6.2 4 6.2 - -1 1.6 - - 8 12.6 - - 1 1.6 4 6.2 Peniophora sp. Stereum sanguinolentum Stereum purpureum basidiomycete 1 basidiomycete 2 2 3-1 - - 2 3«1 basidiomycete 3 _ _ 1 1 . 6 unidentified" 1 3 ^.7 1 1.6 4 6.2 Total 22 3^.3 13 20.4 29 45.3 a includes groups 4-8 inclusive and mixed cultures. 32 considering woodwasps are most active i n dry warm weather. Many of the infections, hox^ever, apparently occurred e a r l i e r than the expected time of oviposition i n mid-August and September ( S t i l l w e l l , 1966), Peniophora sp. and S_. purpureum were predominant i n branches pruned during the wet period of growth, C. laeve occurred i n dormant and active-wet pruned branches. Other basidiomycetes were not iso l a t e d frequently enough to determine trends. In more than 90$ of the sections examined a resin streak occurred i n the annual ring corresponding to the year of pruning. However, i t was seldom pronounced beyond the l i m i t s of the wound. Based on chi-square tests of independence, the difference i n incidence of basidiomycetes with increasing wound size (Table 8) was Table 8, Incidence of balsam f i r pruning wounds infected with basidio-mycetes according to wound size. Wound size ( i n . 2 ) Number examined Number3-infected Percentage Infected Small (0.1-1.0) 104 16 15 . Medium (1.1-2.5) 69 b 21 - 30 Large (2 .6-5.5) 37 13 35 Totals and average 210 50 24 a Total of f i e l d and laboratory culture results. b Differences between small and medium, and between small and large are significant at the 5$ l e v e l of probability. 33 s i g n i f i c a n t at the 5$ l e v e l . Moreover, a s i g n i f i c a n t l y greater number of wounds with injured sapwood contained basidiomycetes than those wounds with uninjured sapwood. There was, however, no r e l a t i o n at the 5$ l e v e l of significance between the occurrence of basidiomycetes and: pruned branch diameter (at least within the 0.3 to 0.6 i n . range tested), branch status, compass orientation, height above the ground or dbh, t o t a l height-, age or average terminal, growth of the tree. Similarly, a scatter graph revealed no correlation between tree dbh and the amount of decay attributed to pruning. Nor was there a correlation between percent of the bole with decay and the number of i n f e c t i o n courts. This may not be true were only one fungus considered, but no single basidiomycete occurred frequently enough to determine a relationship. F r u i t Body Survey A variety of f r u i t bodies were present i n the study area both on conifers and girdled hardwoods (Table 9 ) . Five were species commonly known to attack coniferous trees, f i v e occur only rarely on softwoods, and the balance are r e s t r i c t e d to hardwoods. Also collected were three saprophytic fungi, Dasyscyphus a g a s s i z i i , Aleurodiscus amorphus and Dermea balsamea; the l a s t two occasionally act as weak parasites causing cankering and dieback of balsam f i r (Conners, 196?). C u l l Survey of Pruned Trees Balsam F i r A l l f i v e pruned trees examined i n each area, Green River (A), Table 9 . Fruit bodies of wood-decay fungi collected from standing dead trees and slash near the sit e of the pruning study at Acadia Forest Experiment Station. Host Organism Balsam f i r and black spruce Balsam f i r Trembling aspen "White birch Red maple Polyporus abietinus Lenzites saepiaria Fomes pinicola Fomes p i n i Stereum sanguinolentum Stereum purpureum Pleurotus ostreatus Polyporus pargamenus Polyporus dryophilus var. vulpinus Polyporus dryophilus Stereum purpureum Fomes fomentarius Polyporus betulinus Lenzites betulina Fomes connatus Type of decay caused3-White rot of coniferous, or rarely, broad-leaved trees. Brown rot of coniferous, or rarely, broad-leaved trees. Brown rot of coniferous and broad-leaved trees. Red ring rot of coniferous, rarely broad-leaved trees. Brown heart rot of coniferous trees. White rot of broad-leaved and coniferous trees. and or or White rot of broad-leaved, rarely, coniferous trees. White rot of broad-leaved, rarely, coniferous trees. White rot of Populus spp. White rot of broad-leaved trees White rot of broad-leaved and coniferous trees. White rot of broad-leaved trees Brown rot of Betula spp. 'White rot of broad-leaved, or rarely, coniferous trees. White rot of broad-leaved trees, expecially Acer spp. a from Nobles, 19^8; 1965 . Table 10. Data on 5 balsam f i r trees i n each of 3 pruned — — ^ Avg. Avg. V o l . of decay Avg. A v g i N u m b e r examined and percentage dbh age at a f t e r pruning, pruned wound i n f e c t e d with basidiomycetes Area Date (in . ) base Avg./ Range branch area L i v i n g branches Wounds p r u n e d (yr.) tre e ($) diameter ( i n .2) (no.) {%) (no.) ($) (fo) ( i n . ) 1__W 2 Green River (A) Aug./60 3-8 3^  0.47 .02-2.08 .22 3.1 60 5.0 38 7.9 Crowd!s Mt. (B) June/62 3.4 37 1.66 .77-*+.59 .32 2.3 70 4.3 73 8.2 Crowd!s Mt. (C) 3ept./63 2.8 24 3.06 . 3 3 - ^ . 2 5 .30 1.9 77 5.2 58 20.7 Avg. 3.3 32 1.73 .28 2.4 4.8 12.4 36 Crowdis Mountain (B) and Crowdis Mountain (C) contained measurable decay-attributed to pruning. As also shown i n Table 10, average volume of decay per tree and numbers of infe c t i o n courts were least f o r trees pruned during August, intermediate i n June and highest i n September, This trend i s supported by l i t t l e evidence, but records from the weather station nearest each pruned stand reported only 3 days during August, I960 with measurable precipitation and a mean temperature 36 to 60 F, Corresponding figures f o r June, 1962 and September, 1963 are 7 and 13 days respectively. One or more decay-causing basidiomycetes (Table 11) were isolated from 9 of 15 trees. Each tree had an average of 8 dead (black) knots, Ik l i v e (green) knots and 11 measurable wounds s t i l l evident as e l l i p t i c a l slashes on the bark (Fig. 11). No decay was noted i n two unpruned trees i n each area. Table 11. Number of knots and wounds from which basidiomycetes were isolated i n 5 balsam f i r trees i n each of 3 pruned stands. Location of pruned stand Basidiomycete Green River (A) Crowdis Mt. (B) Crowdis Mt. (C) Stereum sanguinolentum 1 8 10 Amylostereum c h a i l l e t i i - - k Polyporus abietinus 1 - -Peniophora sp. - 1 -unidentified k - 2 Total 6 ,9 16 37 Figure 1 1 . Evidence of wound on balsam Radial section of same wound from which ( r i g h t ) . f i r 4 years a f t e r pruning ( l e f t ) . Stereum sanguinolentum was i s o l a t e d Of nearly 500 knots or wounds examined, discolored wood was associated with 8$ of the dead knots, 12$ of the l i v e knots and 59$ of the wounds. Decay-causing fungi were obtained i n culture from 0, 4.8$ and 12.0$ of these i n j u r i e s , r e s p e c t i v e l y . As shown i n 'Table 12, a large] proportion of cultures from discolored t i s s u e s contained basidiomycetes, imperfect fungi and b a c t e r i a , but fewer were s t e r i l e than from apparently normal wood.' White Spruce Only f i v e pruned and two unpruned-white spruce were examined and the sample i s too small f o r meaningful conclusions. Nevertheless, 38 Table 12. Frequency of i s o l a t i o n of d i f f e r e n t organisms i n apparently normal and di s c o l o r e d wood associated with pruned branches of balsam f: Cultures from Organism(s) Apparently normal wood Discolored wood (no. = 358) (no. = 135) Basidiomycetes Bacteria/lmperfects S t e r i l e 0.8$ B4.1 65.1 18.5$ 60.0 21.5 basidiomycetes were i s o l a t e d from two of f i v e pruned trees and measurable decay occurred i n one of these trees (2.04$ of volume), and one other (0.55$) from which no decay fungi were i s o l a t e d . The trees averaged 35 years at stump height and 4.1 i n , dbh. One of the 50 dead knots y i e l d e d Peniophora sp. i n culture and S. sanguinolentum and Corticium laeve were 2 i s o l a t e d from 2 of the 42 wounds. Average wound s i z e was 2.4 i n . and the average branch diameter at the time of pruning was .34 i n . DISCUSSION Pruning of balsam f i r trees should be done c a r e f u l l y or not at a l l i f some of them are to be used f o r wood or pulp. Only 1-f years a f t e r 7 branches were pruned on each of 3° tr e e st 28 trees had measurable decay averaging 3.9$ of the stem volume, and during f i e l d c u l t u r i n g , wood decay 39 fungi were i s o l a t e d from 31A% of 70 wounds or knots. The l a t t e r percentage i s probably an underestimate as there are several reasons why i t I s p r a c t i c a l l y impossible to obtain cultures from a l l i n f e c t i o n s of wood-destroying fungi (13asham, Mook and Davidson, 1953)' Davidson £1955) obtained successful cultures from only 36.6% of the butt decay examined i n the Green River area. S i g n i f i c a n t differences were present between the occurrence of basidiomycetes and c a r e f u l and careless pruning and among the times of c u l t u r a l i s o l a t i o n , but not among the times of pruning (Table 4). Careful saw pruning, however, was not b e t t e r than c a r e f u l axe pruning. Perhaps the rough surface of the sawn branch stub compared to the smooth axe pruned surfaces provided a niche more favorable f o r basidiospores. I n f e c t i o n was l e a s t i n those branches pruned during the dry period p o s s i b l y due to l e s s favorable conditions f o r d i s p e r s a l and germination of basidiospores, or the "higher temperatures may have reduced the chances of i n f e c t i o n (of S. sanguinolemtum) by causing a temporary "breakdown" i n the observed s e l e c t i v i t y of balsam f i r heartwood, thus favoring the c o l o n i z a t i o n of the wound by competing f u n g i " (Davidson and Etheridge, I963). Numerous workers (Shigo, 1967; Etheridge, 1961 and Whitney, 196l) have considered the r e l a t i v e frequency of i s o l a t i o n s of an organism from branches or wounds dead or exposed f o r known periods of time as an i n d i c a t i o n of the probable course of succession. Each worker found b a c t e r i a and non-decay fungi among the f i r s t organisms to invade and decay fungi the l a s t . S i m i l a r trends were suggested by i s o l a t i o n s made 2 to 3 weeks, 5 to 7 months, and 17 t o 19 months following pruning of balsam f i r ( F i g . 6). 40 I n i t i a l l y 96$ of the i s o l a t i o n s were negative, but w i t h i n 2 to 3 weeks t h i s had dropped to 15$ with dematiaceous imperfect fungi present i n more than 50$ of the i s o l a t i o n attempts. Only 1$ of the cultures contained b a s i d i o -mycetes. Five to seven months a f t e r the branches were pruned, the percentage containing b a c t e r i a rose sharply to 38. One year l a t e r the percentage of cultures containing b a c t e r i a and basidiomycetes had r i s e n to 69 and 20, r e s p e c t i v e l y . These r e s u l t s f o l l o w the expected pattern of succession, beginning with wood d i s c o l o r a t i o n soon a f t e r the bark i s ruptured and which i s probably i n i t i a t e d by chemical changes, but enhanced by organisms. Siegle (1967) found fungi the main producers of the phenol oxidases which catalyze the d i s c o l o r a t i o n process. I n i t i a l invasion by wood saprophytes, imperfect fungi and ba c t e r i a , induces a s t a i n , a high pH, and a high moisture content. As the s t a i n i s destroyed, the pH and water content f a l l and the wood decay organisms dominate (Good, Basham and Kadzielawa, 1968 and Good and Spanis, 1958). The continuing increase i n incidence of bacteria- suggests that basidiomycetes do not simply replace the b a c t e r i a and imperfect f u n g i , but rather e x i s t w i t h them. E i t h e r b a c t e r i a or imperfect fungi were i s o l a t e d i n immediate a s s o c i a t i o n with most of the basidiomycetes. This i s not sur p r i s i n g as ba c t e r i a are considered pioneers i n the wood decay process because of t h e i r a b i l i t y to increase thiamine (many basidiomycetes require thiamine)content of the substrate ( F r i e s , 1938). Bourchier found Bourchier, R. J . (Unpubl. rep., 1967). Wetwood and bacteria i n balsam f i r i n the Maritime Provinces. Can., Dep. Forest. Rural Develop., Intern. Rep. M-21. S. sanguinolentum mycelium produced i n l i q u i d shake cultures containing bacteria weighed about three times that produced i n bacteria-free cultures. Even less i s known of the role played by A, pullulans or many of the other imperfect fungi. Phialophora spp., the most commonly occurring moniliaceous fungi i n t h i s study, are capable of darkly staining red maple (Shigo, 1965)» but l i t t l e Is known of t h e i r role i n successional patterns or t h e i r effect upon wood properties. Numerous hyphae were observed to penetrate c e l l walls of a few wood sections which yielded cultures of Penicillium spp. or unidentified imperfect fungi, M e r r i l l (1965) found weight loss and hyphal penetration by numerous common imperfect fungi i n wood fiberboards. Obviously more work i s required on the association of bacteria and imperfect fungi with the higher fungi. Further work on succession should involve trap bolts or some means of l i m i t i n g the period of possible Infection. One of the greatest problems of successional studies based on frequency of occurrence of spe c i f i c organisms i s the uncertainty of infection time. I t i s not known, for example, whetter the basidiomycete enters the wound at the same time as the primary invaders and simply grows slowly u n t i l the substrate i s prepared or i f indeed i t s entry i s delayed. In t h i s work the basidiomycetes could occur less frequently i n i t i a l l y as suggested, or they could be more frequently isolated l a t e r simply because they have advanced further. Some basidiomycetes l i k e S. sanguinolentum may only be primary Invaders where the host i s only susceptible to infection following summer produced i n j u r i e s for about 24 hr (Etheridge, 1965)? or up to 7 days with Fomes annosus (Cobb and Schmidt, 1964). Information regarding the i n f e c t i o n process i s lacking fo r the less aggressive basidiomycete invaders. 42 Research i s needed on the effect of incipient and advanced decay on the y i e l d and quality of pulp produced. Even before wood reaches the m i l l there may be much loss as incipient decay causes sinkage during water transport (Bakuzis and Hansen, 1965). In addition, shorter periods of yard storage may be required as pulpwood or chips may decompose fas t e r following the introduction of fungi after pruning. Such general statements as "even small amounts of decay i n balsam f i r pulpwood cause serious reductions i n yields and brightness of groundwood pulps" and " i n the sulphite process decay affects the pulp produced more than for any other pulping process" (Glennis and Schwartz, 1952) have been made f o r Worth American wood species. Beath (1956) believes that for e f f i c i e n t operation of modern high speed paper machines decayed wood should make up less than 5$ of wood used at any one time. These references, however, f a i l to account f o r differences between white rots and brown rots or to distinguish between in c i p i e n t and advanced decay. In Sweden Bjorkman et a_l* (1964) found fungi that attack cellulose and l i g n i n to approximately the same extent (S. sanguinolentum, Fomes pint), and present i n a f a i r l y advanced stage of development (firm dark rot), caused a 3-5$ reduction i n weight y i e l d of sulphite pulp with mixtures of 10$ by volume of decayed wood to corresponding sound spruce and pine wood. Pulp brightness was considerably lower, but the strength p r a c t i c a l l y unchanged. Similar loss extimates are needed i n Canada. In the Maritime Provinces the future of Christmas tree-pulpwood management plans i s uncertain. The projection of present decay rates and .volumes i s unreliable, but the consistency of decay i n trees with only 7 pruned branches suggests that decay w i l l be significant i n balsam 43 f i r trees after as many as 40 to 60 branches per tree have been pruned. This study reports the presence of more decay i n younger trees than 8/ similar studies of unpruned trees . There was, however, considerable variation between areas. The average volume of decay per tree f or Green River, Acadia Station, and the two Crowdis Mountain areas were respectively 0.5, 3«9» 1.7 and 3>1$« Similarly, basidiomycetes were associated with 6.1, 46 . 6 , 6.3 and l l e 8 $ of the pruned branches at these locations (Tables 5 and 10). The high incidence at Acadia and the variety of basidiomycetes isolated (Table 6) may stem from the open, mixed wood stand and the .abundance of softwood and hardwood slash providing f or a large basidioapore inoculum. Also, the open stand may be conducive to the build up of Sirex woodwasp populations, hence the abundance of A. c h a i l l e t i i i n pruned trees. The percentage by volume of decay may vary i n trees pruned !§• to 7 years ago because the i n i t i a l rate of extension of a heart rot fungus i n a tree may be much more rapid than that prevailing l a t e r and may stop almost completely after a r e l a t i v e l y rapid i n i t i a l advance (Wagener and Davidson, 1954). More i s known, however, about the amounts of decay after a period of time than about annual rates of decay. The low volume of decay i n the Green River area may be due to many pruned branches being l e f t with long stubs. Furthermore, no Infection occurred at Acadia through branches clipped 4 to 6 i n . from the bole, so clipping branches at a distance from the bole may reduce the incidence of decay, increase volume growth and provide a good lower whorl of branches 17 Smerlis, 1961; Davidson, A. G. (Unpubl. rep., 1951) A study of decay i n balsam f i r (Abies balsamea (L.) M i l l . ) i n the Green River Watershed of New Brunswick. for Christmas trees. This of course would only be suited to a Christmas tree-pulpwood operation for i t would be many years before clear wood was formed. Differences i n amount of infection by trunk decay fungi could be due to factors associated with spore germination and infection (Davidson, 1955)- Spore formation, liberation and dispersal might also be involved but v i r t u a l l y nothing i s known of required conditions for even the most common and important of decay fungi. Were more known, i t might be possible to prune when conditions were least favorable for the fungus. This study has indicated that hot dry periods may be best for pruning which agrees with recommendations for pruning plantations i n Kenya (Griffen, 1967). I t i s apparent that pruning of balsam f i r , whether by axe or saw, i s not to be recommended i f discoloration and decay are to be avoided i n a crop retained for a pulpwood harvest. Further research i s needed on: ( l ) branch removal by clipping remote from the bole thereby reducing injuries which provide entry courts for decay fungi; (2) weather conditions favorable for basidiospore production, dispersal, germination and infection; (3) the role of bacteria and imperfect fungi i n the discoloration and decay process; (4) the annual rate and t o t a l expected amount of decay following i t s entry into the stem; and (5) the effect of white and brown rots i n varying amounts on f i n a l y i e l d and quality of pulp. When this knowledge i s at hand, pruning operations may be timed with conditions unfavorable to the i n i t i a t i o n of discoloration and decay or at least to know what losses to expect i n the end product. 45 2/ REFERENCES Andrews, S. R, 1954. E f f e c t of pruning on western red rot i n young ponderosa pine i n the southwest. J . Forest. 52s 33-38. Anonymous. I963. Native trees of Canada. Can., Dep. Forest., B u l l . 6 l Ottawa. 291 pp. Bagchee, K. and B. K. Bakshi. 1950• Some fungi as wound parasites on Indian t r e e s . Indian Forest. ?6s 244-253• Bakuzis, E. V. and H. L, Hansen. 1965. Balsam f i r , a monographic review. Univ. Minnesota Press, Minneapolis. 445 pp. Barnett, H. L. I960, I l l u s t r a t e d genera of imperfect f u n g i , Burgess .Publ, Co, Minneapolis, 225 PP« Basham, J . T., P. V. Mook and A. G, Davidson. 1953• New information concerning balsam f i r decays i n eastern North America. Can. J. Sot. 31: 334-360. • • and Z. J . R. Morawski. 1964. C u l l studies, the defects and associated basidiomycete fungi i n the heartwood of l i v i n g trees i n the fore s t s of Ontario. Can., Dep. Forest., Publ, 1072. Ottawa, 69 pp. Bauger, E. and A. Orlund. 1962. A study of pruned trees of S i t k a spruce, Abies grandis, western hemlock, Norway spruce, and Thuja p l i c a t a . (Eng. sum.) For. Res. I n s t . West Norway. Publ. 36s 173-197-Baxter, D. V. 1967. Disease In for e s t plantations! t h i e f of time. Cranbrook I n s t . S c i . , B u l l . 51• 251 pp. Beath, L. R. 1956. The use of stained and rotten wood i n the manufacture of newsprint. Forest. Chron. 32* y^-l-^k-^. Bjorkman, E. et a l . 1964. The use of decayed wood from some conifers and broadleaf trees f o r chemical pulping purposes. Stud. Forest. Suecia, Stockholm. 66 pp. T Abbreviations i n accordance with American Standard f o r P e r i o d i c a l T i t l e Abbreviations, 1963. Amer. Stand, Ass. N.I. 19 pp. 46 Childs T. ¥. and E. Wright. 1956. Pruning and occurrence of heart rot i n young Douglas f i r . U. S„ Dep. Agr, P a c i f i c N. W. Forest Range Exp. Sta., Res. Note 132, 5 PP» Cobb, F, W. and R. A. Schmidt. 1964. Duration of s u s c e p t i b i l i t y of eastern white pine stumps to Fomes annosus. Phytopathology 54i 1216-1218. Conners, I. L. 196?. An annotated index of plant diseases i n Canada. Can., Dep. Agr., Publ. 1251, Ottawa. 38I pp. Davidson, A. G. 1955• Decay of balsam f i r (Abies balsamea (lO M i l l . ) i n the Maritime Provinces of Canada, Ph.D. Thesis, Univ. Toronto. 88 pp. and C. E, Brown. 1968, Disease cause code. Can,, Dep. Forest. Rural Devlop. 164 pp. and D. E. Etheridge. 1963, Infection of balsam f i r , Abies balsamea (L.) M i l l , by Stereum sanguinolentum (Alb. and Schw. ex Fr.) Fr. Can. J . Bot. 4ls 759-765> and D. R. Redmond, 1957• Decay of spruce i n the Maritime Provinces. Forest. Chron. 33s 373-380, Etheridge, D. E. 1965. Factors affecting infection of balsam f i r by Stereum sanguinolentum. Proc. Can. Phytopathol. Soc. 31 * 12. . I96I. Factors affecting branch infection i n aspen. Can. J. Bot. 39s 799-816. Finnis, J. M. 1953• Experimental pruning of Douglas f i r i n B r i t i s h Columbia. B r i t . Columbia Forest Serv., Res. Note 24. 26 pp. Fries, N. 1938. Uber die Bedeutung von Weichsstoffen fur das Wachstum verschiedenes P i l z e . Symbolae Bot. Upsaliensis 3 ' 1-188. Funk, A, I960. Descriptions of cultures of Fungi Imperfect! and Ascomycetes associated with forest damage i n B r i t i s h Columbia. Can., Dep. Agr., Forest B i o l , Div., V i c t o r i a . 17 pp. Glennis, D. W. and H. Schwartz. 1952. Pulpwood decay: effect on y i e l d and quality. Paper Ind. 34: 738-740. Good, H. M.«,J. T. Basham and S. D. Kadzielawa, 1968, Respiratory a c t i v i t y of fungal association i n zones of heart rot and stain i n sugar maple. Can, J . Bot. 46: 27-36. and W. Spanis. 1958. Some factors affecting the germination of spores of Fomes igniarius var. populinus (Neuman) Campbell, and the significance of these factors i n in f e c t i o n . Can. J. Bot. 36: 421-437. 47 G r i f f i n , H. D. 1967. Further studies on Stereum sanguinolentum A l b . and Schw, ex F r i e s i n Kenya f o r e s t p l a n t a t i o n s . (Abstr.) Forest. A b s t r . 29i 851. H a r r i s , A. S. 1966. A t e s t of pruning S i t k a spruce i n Alaska. U, S. Dep. Agr. Note NOR-13. 3 pp. Hawley, R. C. and R. T. Clapp, 1935. A r t i f i c i a l pruning i n coniferous p l a n t a t i o n s . Tale Univ., Sch. Forest. B u l l . 39s I-36. Herman, D. ¥ . 1963. Pruning conifers f o r the production of q u a l i t y timber. B r i t . Forest. Comm., B u l l . 35. 55 pp. Hubert, E. E. 1954. I s o l a t i o n s of fungi i n the f i e l d using the Swedish increment hammer, J , Forest, 52: 131. Kaufert, F. 1935* Heart rot of balsam f i r i n the Lake States, with s p e c i a l reference to f o r e s t management. Agr. Exp. S t a . , Univ. Minnesota, Tech, B u l l . 110. Keeping, E. S, 1962. Introduction to s t a t i s t i c a l inference. Van Nostrand, Prunceton, N. J . 451 pp. Lohrey, R. E. 1963. Healing time f o r pruning wounds i n a red pine p l a n t a t i o n . U. S, Dep. Agr., Res. Note LS - 24. McGalium, A. W. 1928. Decay i n balsam f i r (Abies balsamea M i l l . ) . Can., Dep. Agr., B u l l . 104, Ottawa, McLeod, J . ¥. 1968. Christmas t r e e management In the Maritime Provinces. Can., Dep. Forest. Rural Develop., Inform. Rep. M-X-15. 54 pp. M e r r i l l , W. 1965. Decay of wood and wood fiberboards by common fungi i m p e r f e c t i . Holz. und Organismen Internationales Symp., B e r l i n , p. 69-76. Nobles, M. K. 1965• I d e n t i f i c a t i o n of cultures of wood-inhabiting hymenomycetes. Can. J . Bot. 43: 1097-1139. , 1948. Studies i n f o r e s t pathology. ICC, I d e n t i f i c a t i o n of cultures of wood-rotting f u n g i . Can. J , Res. 26: 281-431. Ralston, R. A. and ¥ . Lemien. 1956. Pruning pine plantations i n Michigan. Michigan State Univ., B u l l . 221. 27 pp. R i s l e y , J . H. and S. B, S i l v e r b o r g . 1958. Stereum sanguinolentum on l i v i n g Norway spruce following pruning. Phytopathology 48: 337-338. Roth, E, R. 1939. The e f f e c t of pruning on the heartrot hazard i n hard-woods. U. S. Dep. Agr. Mimeo. 9 pp. 48 Rowe, J. S, 1959. Forest regions of Canada. Can., Dep. N. A f f . Nat. Resources, B u l l . 123. Ottawa. 71 pp. Shigo, A. L, 1967. Successions of organisms i n d i s c o l o r a t i o n and decay of wood. I n t . Rev. Forest Res. 2: 237-299. . 1965. Decay and d i s c o l o r a t i o n i n sprout red maple. Phytopath-ology 55s 957-962. S i e g l e , H. I967. M i c r o b i o l o g i c a l and biochemical aspects of heartwood s t a i n i n Betula papyrifera Marsh, Can. J. Bot. 45: 147-154. S h i l l i n g , D. D. 1958. Wound healing and defects f o l l o w i n g northern hardwood pruning, J . Forest. 56s 19-22. S l e e t h , B. 1938. Pruning wounds as an avenue of entrance f o r fctereum sanguinolentum i n northern white pine p l a n t a t i o n s . U, S, Dep. Agr,, Allegheny Forest Exp, Sta,, Tech. Note 22: 1-3« S m e r i l i s , E. 1961, Pathological condition of immature balsam f i r stands of Hylocomium - Oxalis type i n the Laurentide Park, Quebec. Forest. Chron. 37s 109-115. Spaulding, P. and J, R, Hansborough. 1944, Decay i n balsam f i r i n New England and New York. U. S. Dep. Agr., Tech. B u l l . 872 and H, J . MacAloney. 1935* Stereum sanguinolentum, a dangerous fungus i n pruning wounds on northern white pine. U. S, Dep. Agr., N. E. Forest Exp. Sta., Tech, Note 19, 2 pp. S t i l l w e l l , M, A. 1966, Woodwasps ( S i r i c i d a e ) i n conifers and the associated fungus, Stereum c h a i l l e t i i i n eastern Canada. Forest S c i . 12: 121-128. Toole, E. Ro 196l. Rot entrance through dead branches of southern hard-woods. Forest S c i . "J% 218-226. Van S i c k l e , G. A, i960. Assessment of decay i n pruned coniferous stands i n Nova S c o t i a . Can., Dep. Forest, Rural Develop., Inform. R-ep. M-X-4. 10 pp. Wagner, W, W. and R. W. Davidson. 1954. Heart rot s i n l i v i n g t r e e s . Bot0 Review 20: 61-134. Whitney, R. D. 1 9 6 l . Root wounds and associated root vots of white spruce, Forest. Chron. 37: 401-411. APPENDIX I Botanical and common names for tree species referred to i n text. 10/ Botanical Name Common name Abies balsamea (L.) M i l l . Balsam f i r Abies grandis (Dougl.) L i n d l . Grand f i r Picea abies (L.) Karst. Norway spruce Picea glauca (Moench) Voss White spruce Picea mariana ( M i l l . ) BSP. Black spruce Picea rubens Sarg. Red spruce Picea sitchensis (Bong.) Carr. Sitka spruce Pinus ponderosa Laws. Ponderosa pine Pinus resinosa A i t . Red pine Pinus strobus L. Eastern white pine Pseudotsuga menziesii (Mirb.) Franco Douglas-fir Thu.ia p l i c a t a Donn Western red cedar Tsuga heterophylla (Raf.) Sarg. Western hemlock Acer rubru.m L. Red maple Acer saccharum Marsh. Sugar maple Betula alleehaniensis B r i t t . Yellow birch Betula papyrifera Marsh. White birch Populus tremuloides Michx. Trembling aspen Ulmus americana L. White elm w Nomenclature i n accordance with that Can., Dep. Forest. B u l l . 61. 1963. used i n Native Trees of Canada, 50 APPENDIX I I I i / Botanical names for fungi referred to In text. Aleurodiscus amorphus (Pers. ex Fr.) J. Schroet. Amylostereum c h a i l l e t i i (Pers. ex Fr.) Boidin, A r m i l l a r i a mellea (Fr.) Kummer. Aureobasidium pnllulans (D By.) Arnaud Corticium laeve Pers. ex Fr. Dasycyphus a g a s s i z i i (Berk, and Curt.) Sacc. Dermea balsameae (Pk.) Seaver Forties anhosus (Fr.) Karst. Pomes connatus (Weinm.) G i l l . Fomes fomentarius (L. ex Fr.) Kichx Fomes p i n i (Thore ex Pers.) Lloyd Fomes pinicola (Sw. ex Fr.) Cke. Hypoxylon dexstum (Hoffm. ex Fr.) Grev. Lenzites betulina (L. ex Fr.) Fr. Lenzltes saepiaria (Wulf. ex Fr.) Fr, Pleurotus ostreatus (Jacq. ex Fr„) Kumm. Polyporus abietinus Dicks, ex Fr, Polyporus anceps Pk, Polyporus betulinus B u l l , ex Fr. Polyporus dryophilus Berk, Polyporus dryophilus var. vulpinus (Fr.) Overh. 11/ Nomenclature i n accordance with that used by Davidson and Brown (1968). Disease cause code. Can., Dep. Forest, and Rural Devlp. 164 pp. APPENDIX II (continued) Polyporus pargaraenus F r . Retinooyclus a b i e t i s (Crouan) Groves and Wells Stereum purpureum (Pers. ex Fr.) F r . Stereum sanguinolentum (Alb. and Schw. ex Fr.) APPENDIX I I I . Schedule of pruning and culturing for 33 balsam f i r trees at Acadia Forest Experiment Station, New Brunswick. Pruning and branch stub cultures (2 isolates each branch) Field cultures (3 isolates each knot) Time after pruning 2-3 weeks 5-7 months 17-19 months Laboratory cultures (3 isolates each knot) A l l recultures November 23, 196? wound (A) Dormant March 23, 1966 branch (B) wound (C) Active-dry July 4, 1966 branch (D) wound (E) i.ctive-wet branch (F) June 9, 1966 branch (G) (saw) Tree nos. Tree nos. 27.16.14.25, 22,2 ,20,18, 21.15.13.26, 5 ,7 ,23 ,4 ,9 , 24,19,(32) 29,(31) Group I Group i l A p r i l 6, 1966 October 17, 1966 Group I I I Group I July'22, 1966 October 17, 1966 Group I I Group I I I June 28, 1966 October 17, 1966 Tree nos, 12,8,28 ,30, 1 7 , 3 , 6 , 1 , 11,10,(33) Group I I I October 17, 1967 Group I I October 17, 1967 Group I October 17s 1967 Group I I I October 23-31, 1967 Group I I October'23-31, 1967 Group I October 23-31, 1967 APPENDIX iv. Related data for a l l wounds or knots from which basidiomycetes were i s o l a t e d i n 30 pruned balsam f i r a t Acadia Forest Experiment Station.' Tree Tree Dia- Wound Size Compass Height no & Age dbh Height % of meter Length Width Area1' orien- wound Field Lab Insect branch (years (in.) (ft) volume of (in.) (in.) ( i n / ) tation above Cul- cul- g a l l -op v±th pruned of ground tures^ tures° eries stump) decay branch (in.) wound (ft) 1 A a 48 2.8 17.4 17.22 0.7 7.3 1.5 5.5 N 6 FI, b Ac,Sp,FI -B 0.6 1.5 1.0 1,2 ¥ 6 FI,b Ac.FI.b -2 C 33 2.0 15.6 1.16 0.4 2.0 1.0 1.0 E 7 Pl.FI FI,b -D 0.3 0.6 0.6 0.3 E 6 Bl.FT F l -3 _ A 35 1.8 13.8 9.69 0.2 3.5 0.8 1.4 S 4 FI,b Ac -- E 0.4 4.5 1.0 2.2 N 5 C1,FI, b — — — 4 - B 45 2.2 15.0 14.83 0.5 1.0 0.7 0,6 ¥ 5 B5.FI, b _ _ _ -C 0.4 5.5 1.0 2.8 S 4 FI,b Ac + —• D 0.4 1.5 1.3 1.5 s 7 FI,b Ac + 6 A 35 3.0 22.6 7.09 0.4 2.3 1.0 1.2 S 6 C1,B5, Ss,B5 -b,FI G 0.5 0.8 0.7 0.4 ¥ 6 B2.FI _ _ _ -8 — A 47 2.6 19.3 2.07 0.4 5.0 1.2 3-0 ¥ 7 Cl,b Cl -B 0.6 1.4 0.9 1.0 S 7 C1,FI Cl -9 — C 52 3.7 27.6 2.72 0.4 3.0 1.4 2,1 N 6 FI,b Ac,b D 0.4 0.8 0.8 o.5 ¥ 6 FI,b Ac,b + — E 0.4 2.2 1.4 1.5 N 5 P1,FI _ _ _ -APPENDIX IV. (continued) Tree Tree Dia- Wound Size Compass Height F i e l d Lab Insect no • & Age dbh Height ,0 OX meter Length Width Area" orien- wound branch volume of ta t ion above Cul-c c u l - g a l l -with decay pruned branch of wound ground tures tures 0 eries 10 - A 46 4.9 29.7 0.33 0,4 3.2 1.5 2.4 E 4 Cl,b C l . F I , b -12 - A 52 2.7 20.2 18.88 0.4 2,0 1.0 1.0 E 6 Cl.FI, b Ac,b + - D - E 0,4 0.6 1.0 0.5 N 4 A c . F l _. _ _ -0.4 3.5 1.0 1.8 W 4 B3,FI,b -15 - E 38 4.3 29.7 0.02 0.5 4.0 1.7 3.4 E 6 C l , P2 Cl -16 - E 37 2.8 19.0 4.23 0.4 2.5 • 1.5 2.1 E 5 FI,b Sp — - G 0.3 0.7 0.7 0.4 W 4 b,FI Sp -17 - A 4.6 28.8 3.58 0.5 4.5 1.5 3.4 W 5 Cl ,b , Cl,Ss -F l 18 - C 48 2.6 16.2 9.09 0.5 3.5 1.2 2.1 N 4 FI,b Ac, b - D 0.5 3.0 0.7 2.7 N 6 FI ,b Ac -19 - C 51 5.2 32.1 1.37 0.4 4.5 1.5 3.4 E 4 Ac,FI - - - -- E 0.8 5.0 1.5 3.8 N 8 Sp,b P2 — - F 0.6 1.5 1.5 1.8 S 7 FI ,b Sp -- G 0.5 0.8 1.0 0.6 E 6 FI,b Ac -21 - E 44 5.5 28,8 0.41 0.6 3.2 1.8 2.9 W 5 C1,FI, b B2,b, Cl — 22 - B 21 2.5 20.1 4.76 . 0.4 0.6 0.8 0,4 W 6 _ _ _ -F l 23 - C 26 2.7 20.1 0.92 0,4 3.0 1.0 1.5 w 7 B6,FI, b B7,FI, FI,b -24 - E 36 2.7 20.9 0.47 0.4 7.0 1.0 3.5 E 6 Cl.FI, -b b APPENDIX IV (continued) Tree Tree Dia- Wound Size Compass Height no. & Age dbh Height ' % of meter Length Width Area orien- wound Field Lab Insect branch volume of t a t i o n above cul- cul- g a l l -with pruned of ground tures 0 tures 0 eries decay branch wound 2 5 - E 34 2.7 18 .3 0 .97 0 .5 3 . 5 LL»2 2 . 1 S 6 Sp,FI, b PI -- F 0 .5 1 .5 0 . 5 0 . 8 S 6 Sp,FI, Sp,b -- G 0.4 0,4 0 . 5 0 . 2 E 6 \J B l , Sp,b -26 - E 42 2 .7 18 .5 2 .33 o„5 5 . 5 1 . 0 2 . 8 N 8 Sp,FI Sp -- G 0 .4 0.8 0 . 9 0 , 6 E 7 B1,FI, Cl,b, -b F l 27 - E 29 2 .3 18.0 0 0.2 0 .7 0 . 9 0 . 3 N 3 B4,b, b,FI -F l 29 - B 50 3 . 3 23,4 9 . 2 6 0.4 1.7 0 . 7 X e 1 W 7 3 5 , F l , "h - - - -- C 0 .5 7.0 1 . 5 5.2 S 6 u FI,b Ac + - D 0 .6 1 .5 1 . 0 1.2 N 6 FI,b Ac + 30 - A 36 3.4 2 5 . 3 17 .54 0.4 4 .5 1 .5 3 . 4 S 4 Cl,b Ac,b,FI - E 0.4 5.0 1 . 0 2 . 5 E 5 PI,BR, _ _ _ -FI,b 31 - A 28 2.0 14 .5 2 .47 0 .5 3 . 5 1 . 0 1 .7 W 3 B2,Ss, _ _ _ -F l - F 0.4 3 . 5 1 .2 2 , 1 E 5 B2.FI _ _ _ -32 - E 32 2 . 5 1 7 . 5 0.20 0 .5 5.0 1 .0 2 .5 W 7 B1,FI, "h FI,b -- G 0 .3 0.4 0 . 3 0 . 1 E 5 U Bl.FI FI,b _ 33 - A 28 2 .5 18 .3 2 .94 0 .5 3.0 1 .0 1 .5 W 4 FI ,b Ss,FI -Avg. 39.1 3 . 1 21.4 4.14 0 .45 2 .9 1.1 1.7 5 . 5 APPENDIX IV (continued) a Branches A (careless) B '(careful) axe primed March 23, 1966; C (careless) D (careful) July 4, 1966j E (careless) F (careful) G (sawn) June 9, 1966. b . 2 Wounds A, C, E, diamond shaped, A = L.W ; B, D, F, g more or less c i r c u l a r A = r . 2 c Listed i n order of decreasing number of cultures i n each trees Ac = Amylostereum c h a i l l e t i i Cl = Corticium laeve Ss = Stereum sanguinolentum Sp = Stereum purpureum Bl, 2 ... = unidentified basidiomycete PI, 2= i n Penlophora spp. FI = Fungi Imperfecti b = bacteria — - = not cultured 

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