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Effects of competitor spacing in a new class of individual-tree indices of competition: semi-distance-independent indices computed for Bitterlich versus fixed-area plots.
- Source :
-
Canadian Journal of Forest Research . Apr2008, Vol. 38 Issue 4, p890-898. 8p. 1 Diagram, 1 Chart, 8 Graphs. - Publication Year :
- 2008
-
Abstract
- We illustrate effects of competitor spacing for a new class of individual-tree indices of competition that we call semi-distance-independent. This new class is similar to the class of distance-independent indices except that the index is computed independently at each subsampling plot surrounding a subject tree for which growth is to be modelled. We derive the effects of distance for this class as the expected value over independent samples containing a particular subject tree. In a previous paper, we illustrated distance effects implicit in eight indices of the distance-dependent class. Here, we present distance effects of four semi-distance-independent indices: density, sum of diameters, basal area, and tree-area ratio; each determined for small fixed-area plots of 0.04 ha and for Bitterlich samples of 6 m2·ha–1. We show that several members of this new class have distance effects very similar to the distance-dependent class and should, therefore, be equally effective in accounting for competitive effects in individual-tree increment models. The comparisons should inform selection of competition indices and sampling designs for growth modelling. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00455067
- Volume :
- 38
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Canadian Journal of Forest Research
- Publication Type :
- Academic Journal
- Accession number :
- 32486091
- Full Text :
- https://doi.org/10.1139/X07-192