SITE REGIONS REVISITED - A CLIMATIC ANALYSIS OF HILLS SITE REGIONS FOR THE PROVINCE OF ONTARIO USING A PARAMETRIC METHOD

A climatic analysis was conducted of Hills' site regions for Ontario u sing spatially distributed models of long-term, mean monthly climate d ata. Gridded estimates of eight climatic variables were generated by c oupling thin-plate smoothing spline surfaces (fitted as a trivariate f unction of longitude, latitude, and elevation) to a 1-km resolution di gital elevation model of Ontario. The gridded climate estimates were u sed to characterize the climate of each site region. New climatic clas sifications for the province were calculated from these data using a c lustering algorithm. They were also compared with the existing site re gion boundaries. The analyses confirm many of the general climatic gra dients established by Hills, but also suggest where major revisions sh ould be made. The climatic models present new analytical opportunities for mapping plant-climate response in the context of forest planning and management.