A topographic index to quantify the effect of mesascale landform on site productivity

MCNAB, W.H. 1993. A topographic index to quantify the effeet of mesoscale landform on site productivity. Can. J, For. Res. 23: 1100-l 107. Landform is related to environmental factors that affect site productivity in mountainous areas. 1 devised a simple index of Iandform attd tested this index as a predictor of site index ín the Blue Ridge physiographic province. ‘fhe landform index is the mean of eight slope gradients from plot center to skyline. A preliminary test indicated that the index was significantly associated with slope position and three classes of landform (ridge, slope, and cove). In a test with data from four locations, site index of yellow-poplar (Liriodendron tulipifera L.) was significantly correlated with landform index for each location (r = 0.45-0.65). Landform index and two other topographic variables together accounted for 3 1 percent of the variation in yellow-poplar site index throughout the Blue Ridge province. Landform index is a conveniently measured site variable that may be useful in various forestty-related applications, including multivariate analysis of the distribution and composition of forest vegetation.