Aboveground dry matter partitioning, size variation, and competitive processes within second-growth black spruce stands
Three density-stressed black spruce (Piceamariana (Mill.) B.S.P.) populations that naturally regenerated following harvesting in 1970 were selected for study within central insular Newfoundland. Employing historical tree and stand reconstruction techniques, bark, stem, branch, foliage, and total mas...
| Published in: | Canadian Journal of Forest Research |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1993
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/x93-242 http://www.nrcresearchpress.com/doi/pdf/10.1139/x93-242 |
| Summary: | Three density-stressed black spruce (Piceamariana (Mill.) B.S.P.) populations that naturally regenerated following harvesting in 1970 were selected for study within central insular Newfoundland. Employing historical tree and stand reconstruction techniques, bark, stem, branch, foliage, and total mass distributions were estimated by age-class. Regression analysis was used to assess the effect of density stress on distributional indices, and stepwise multivariate analysis of variance was used to investigate dry matter partitioning patterns. Bark and foliar mass proportions increased with increasing density stress, whereas stem and branch mass proportions declined. Among components, decreased stem proportions best expressed the effects of increasing density stress on dry matter partitioning. Asymmetry within the mass frequency distributions for bark, branch, and foliar components shifted from negative skewness at low relative densities to positive values at high relative densities. Inequality (mass concentration) within the stem mass frequency distributions remained constant, whereas inequality within the bark mass frequency distribution declined in direct proportion to increasing density stress. Inequality within both the branch and foliar mass distributions had curvilinear relationships with increasing density stress: inequality increased from low to intermediate levels of density stress, but declined thereafter. Specific leaf areas did not differ among trees of varying size, suggesting that competition for light may not have been of consequence within the sampled stands. The results are consistent with a resource depletion competitive process, implying that competition within the dense second-growth black spruce stands may have been principally for belowground resources. |
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