Genetic variation and seed transfer guidelines for ponderosa pine in the Ochoco and Malheur National Forests of Central Oregon

Adaptive genetic variation in seed and seedling traits was evaluated for 280 families from 220 locations. Factor scores from three principal components were related by multiple regression to latitude, longitude, elevation, slope, and aspect of the seed source, and by classification analysis to seed zone and elevation band in seed zone. Location variance was significant but not large. Multiple regression equations explained less than 50 percent of location variance. Slope aspect variables were important.