A retrospective study was carried out between 1992 and 1999 in the Cariboo-Chilcotin area of the Southern Interior Forest Region to quantify the effects of trembling aspen competition on lodgepole pine performance and to identify competition indices or other measures of competition that could be used by field staff. In six stands in the Sub-Boreal Spruce (SBS) dw1 and Interior Douglas-fir (IDF) dk3/dk4 biogeoclimatic variants, target pine were selected across neighbourhoods with varying densities of tall aspen (i.e., aspen as tall or taller than the target pine). Data pertaining to pine size and condition, and to the size and location of aspen within a 1.78-m radius of the target pine, were collected three times. Measurements commenced when stands were 7-12 years old. Various approaches were used to identify levels of aspen abundance where pine performance declined below acceptable levels. These included analyses of regression and correlation, tests of existing competition indices, and visual and statistical characterization of trends.
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Updated May 17, 2007