Winter Injury and Developmental Cold Tolerance of Red Spruce

Abstract

Of the numerous hypotheses that have been proposed to explain the reported reduction in vigor, biomass, and regeneration of red spruce (Picea rubens Sarg.) throughout various parts of eastern North America, those related to winter injury are particularly noteworthy because winter injury has been documented in red spruce forests for many years, and red spruce appears to be uniquely susceptible. That is, species sympatric with red spruce are often uninjured, or only slightly injured, by environmental conditions that result in severe winter injury to red spruce foliage. Undoubtedly, the repeated loss of current-year foliage due to winter injury, as frequently as 3 or 4 years per decade, has had a negative impact on the subsequent growth and vigor of injured trees. This chapter represents a comprehensive summary of the current state of knowledge regarding winter injury and cold tolerance in red spruce. It includes discussion of the nature, extent, and probable cause(s) of winter injury to red spruce, descriptions of unique aspects of developmental cold tolerance for this species, and evidence that certain perturbations, including atmospheric pollutants, have contributed directly to the recent high frequency of winter injury and indirectly to the decline of red spruce throughout the northern montane forests of eastern North America.