Winter Injury Susceptibility and Cold Tolerance of Current and Year-Old Needles of Red Spruce Trees from Several Provenances

Abstract

Winter injury to red spruce (Picea rubens Sarg.) trees from 12 provenances in a plantation near Colebrook, NH, was described and quantified in spring 1986 through 1989. Winter injury was found exclusively on current-year needles (i.e., buds and twigs were virtually uninjured), and 34% to 68% of trees were injured each year. Laboratory assessments of cold tolerance of current and year-old needles of trees representing four red spruce and four balsam fir (Abies balsamea [L.] Mill.) provenances indicated that current-year needles of red spruce, but not balsam fir, were 8° to 12°C less cold tolerant than year-old needles in late autumn and early winter. Also, throughout the winter, current-year needles of red spruce were about 10°C less cold tolerant on average than those of balsam fir, a sympatric species that does not suffer winter injury. Thus it appears that a "window" of freezing injury susceptibility exists naturally for red spruce in early winter. Provenance differences in foliar winter injury and percentage of trees injured were highly significant in 1986, 1987, and 1989, and marginally significant in 1988. Trees from Quebec, New York, and New Brunswick were consistently among the least injured each winter, whereas trees from Massachusetts and New Hampshire were consistently among the most injured. It is likely that repeated winter injury is a major contributor to the reported decline of red spruce in northern forests. For. Sci. 36(4):982-994.