Frost avoidance by selection for late budburst in Picea sitchensis.
Abstract
The nature and extent of genetic variation among clones of Queen Charlotte Island provenance was estimated in relation to likely dates of budburst in past years at Eskdalemuir and Braemar (two upland sites with long temp. records), and return times of potentially damaging frosts for early- and late-flushing clones. Mean date of budburst on lateral shoots of young Sitka spruce would need to be delayed by at least 7 days in order to reduce frequency of spring frost damage at these sites from once every 3 yr to once every 4 yr, and by at least 2 wk to avoid frost damage altogether.