PRODUCTIVITY OF SITKA SPRUCE IN NORTHERN BRITAIN .1. THE EFFECTS OF ELEVATION AND CLIMATE

Variation in the productivity of Sitka spruce in upland northern Britain with elevation and location was investigated by establishing 187 temporary sample plots. Productivity (General Yield Class, GYC) was found to decline by about 3.2-4.0m3 ha-1 y-1 per 100m increase in elevation. Correlations between GYC and elevation were high on individual sites but there was considerable site to site variation; GYC values at specific elevations were higher in inland and southern areas than in coastal and northern ones. The geographical distribution of the relationship between GYC and elevation was similar to known patterns of temperature and windiness. Indices of temperature and windiness proved to be highly correlated with productivity. © 1990, Oxford University Press. All rights reserved.