Environmental Influences on Winter Desiccation of Picea glauca Foliage at Treeline, and Implications for Treeline Dynamics in Northern Manitoba

摘要: Abstract Winter desiccation and mortality of coniferous foliage are important determinants carbon balance in trees thus can influence the location subarctic treeline ecotone. The purpose this study was (i) to assess variation winter viability first-year conifer needles at several heights orientations along tree boles across forest-tundra ecotone near Churchill, Manitoba, from 2008 2010, (ii) determine if there is a noticeable needle health on ongoing advance area. Growing season air temperatures around Churchill were significantly cooler 2009, resulting development shorter during 2010. Minimum epidermal conductance (gmin) varied little with height or orientation prevailing wind direction. highest values gmin occurred when previous June (t — 1) 2.9 °C than normal, lowest 2009 1...