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Intraspecific competition processes and their management within black spruce (Picea mariana (Mill) B.S.P.) stands

University of British Columbia

The first primary objective was to assess the applicability of the resource depletion and pre-emption competition hypotheses within density-stressed black spruce (Picea mariana (Mill) B.S.P.) stands. The assessment consisted of analyzing the relationship between response variables of selected subject trees (growth, size, partitioning and allometric indices of aboveground modular components) and directional-specific indices of local competition employing regression analysis, univariate analysis of variance and multivariate analysis of variance. Results from these analyses were in accord with those predicted under the resource pre-emption competition hypothesis: directional-specific asymmetrical relationships in which larger-sized competitors dominated. Decreased branch production and changes in foliar morphology characterized the response of black spruce to increasing competition from above. These results suggest that black spruce may have evolved a highly successful strategy for competing within density-stressed populations situated on nutrient limiting sites: decreased allocation of resources to non-photosynthetic components (decreased branch production), maintenance of the photosynthetic apparatus through adjustments in foliage morphology (increased specific leaf area), and nutrient retainment through foliage retention (foliar-based growth, partitioning and nutrient indices were among the least affected). The second primary objective was to develop stand density management diagrams for natural and managed black spruce stands and demonstrate their utility in competition management. Graphic and algorithmic versions of the diagrams were developed employing data bases derived from permanent and temporary sample plots. The utility of the diagrams was demonstrated by deriving yields for various initial density conditions by site class and subsequently evaluating outcomes in terms of specified operability criteria. The third primary objective was to develop and compare sequential and double sampling designs for point-density estimation and subsequently develop a mathematical compatible approach quantitatively linking point-density estimates to future yields. Although results from sampling simulations indicated that the sequential plan required fewer samples, estimation and precision biases were greater than those obtained when using the double sampling plan. The relationship between point-density estimates and future yields was established through the use of the stand density management diagram: the diagram was used as a simulation model to derive yield estimates for a range of stocking-adjusted initial densities and site classes. Empirical regression relationships were established among the variables and subsequently summarized within a graphical, functional and algorithmic framework.

Thesis/Dissertation

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2009-03-17

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http://hdl.handle.net/2429/6123

Forestry

University of British Columbia

UBCV

DSpace