Perkins T D, Adams G T, Lawson S, Hemmerlein M T
Forest Decline Project, Department of Botany, University of Vermont, Burlington, VT 05405-0086, USA.
Tree Physiol. 1993 Sep;13(2):119-29. doi: 10.1093/treephys/13.2.119.
Red spruce (Picea rubens Sarg.) in high elevation forests of northeastern North America suffers from frequent and severe winter injury, leading to apical dieback, decreased growth, and high mortality. To examine the role of winter desiccation and freezing injury in winter damage, weekly assessments of cold tolerance and water content were made on current-year foliage collected from native red spruce trees at a high elevation site over two winter seasons. In both years, foliage maintained high water contents and adequate cold tolerance; nonetheless, slight to moderate injury was observed each year on some trees. Despite brief thaw periods each winter, no mid-winter dehardening sufficient to put foliage at risk of freezing injury was evident. These findings suggest that, at least in some years, winter injury to current-year red spruce foliage is produced by a mechanism other than desiccation or absolute low temperatures.
北美东北部高海拔森林中的红云杉（Picea rubens Sarg.）经常遭受严重的冬季伤害，导致顶梢枯死、生长减缓以及高死亡率。为了研究冬季干燥和冻害在冬季损害中的作用，在两个冬季里，每周对从高海拔地区的原生红云杉树上采集的当年生叶片进行耐寒性和含水量评估。在这两年中，叶片都保持了较高的含水量和足够的耐寒性；尽管如此，每年在一些树上都观察到了轻微到中度的损伤。尽管每年冬天都有短暂的解冻期，但没有明显的冬季中期脱锻炼现象足以使叶片面临冻害风险。这些发现表明，至少在某些年份，当年生红云杉叶片的冬季伤害是由干燥或绝对低温以外的机制造成的。
