Effects of winter injury on basal area and height growth of 30-year-old red spruce from 12 provenances growing in northern New Hampshire

Basal-area increment and height growth of 30-year-old red spruce (Picearubens Sarg.) from 12 rangewide provenances growing in a plantation in northern New Hampshire were measured for a 3-year period (1986 through 1988) in which severe and (or) frequent winter damage to needles occurred. Growth of uninjured trees and injured trees were compared. Basal-area increments were successively smaller for groups of trees arranged in increasing order of average needle damage as a portion of the upper crown and number of years that the trees were injured. A similar pattern was observed for height growth, but the effect of winter damage was not as great on height growth as on basal-area increment. Growth losses following winter injury, especially height growth, were much greater for trees in provenances classed as pure red spruce than for trees in provenances where introgressive hybridization with black spruce (Piceamariana (Mill.) B.S.P.) has been demonstrated. For pure red spruce populations, repeated injury in 3 successive years or a sustained average of 30% or more needle damage resulted in losses in basal-area increment and height growth of up to 59 and 30%, respectively. Basal-area growth of the most severely injured trees in New England - New York provenances was 63% less than that of uninjured trees. These results support the contention of others that winter injury could be an initiating or perpetuating factor in red spruce decline.