| Fifty-nine trees across New York State were destructively sampled and analyzed to study the effect of inter- and intra-specific competition on tree growth among red pine (Pinus resinosa Ait.), white pine ( Pinus strobus L.) and Norway spruce (Picea abies (L.) Karst.). Four growth rates: relative growth rate (RGR), absolute growth rate (ABS), specific volume increment (SVI) and periodic average volume increment (PAVI) were calculated using the last fifteen years of growth for each tree. Six competition indices were used to find which growth rates and indices were best correlated for each species. SVI had the highest correlation with competition for white pine and Norway spruce, while competition indices were more strongly correlated with ABS in red pine. For all species, distance-independent indices explained the greatest amount of variation in bole growth. There was never a significant difference between inter- and intra-specific competition among mature, even-aged conifers in this study. |
