Predicted global warming and Douglas-fir chilling requirements

Abstract

Pseudotsuga menziesii seedlings from warm coastal and cool mountainous Oregon seed sources, grown under natural conditions, were chilled at constant temperatures of 5, 7 or 9°C for 9, 11, 13 or 15 wk beginning in mid-October. The longest and coldest chilling treatment produced the greatest growth response for all seed sources. -from Authors