Boyce R L, Saunders G P
Department of Biological Sciences, University of Denver, Denver, CO 80208, USA.
Tree Physiol. 2000 Oct;20(16):1077-86. doi: 10.1093/treephys/20.16.1077.
Water relations of Engelmann spruce (Picea engelmannii Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) trees growing at an elevation of 3230 m on Mt. Evans, Colorado, USA, were studied during the winters of 1995-1996 and 1996-1997. During both winters, current-year and 1-year-old shoots were collected weekly and their relative water contents (RWC) determined. Measured meteorological parameters were used in a conifer winter water relations model, WINWAT, to simulate changes in shoot RWC of P. engelmannii and A. lasiocarpa during the winter. The model failed to predict shoot RWCs in 1996-1997 when calibrated with 1995-1996 data. The cold early summer of 1995 inhibited xylem formation, which appears to have caused lower rates of water recharge to the needles during the 1995-1996 winter than during the 1996-1997 winter. We conclude that summer climate strongly affects winter water relations in these subalpine species, and that changes in both summer and winter climate must be considered when predicting future ranges of these species.
对生长在美国科罗拉多州埃文斯山海拔3230米处的恩氏云杉（Picea engelmannii Parry）和亚高山冷杉（Abies lasiocarpa (Hook.) Nutt.）树木的水分关系进行了1995 - 1996年冬季和1996 - 1997年冬季的研究。在这两个冬季，每周采集当年生和一年生嫩枝并测定其相对含水量（RWC）。将测量的气象参数用于针叶树冬季水分关系模型WINWAT，以模拟恩氏云杉和亚高山冷杉嫩枝在冬季的RWC变化。当用1995 - 1996年的数据进行校准时，该模型未能预测1996 - 1997年嫩枝的RWC。1995年寒冷的初夏抑制了木质部形成，这似乎导致1995 - 1996年冬季针叶的水分补充率低于1996 - 1997年冬季。我们得出结论，夏季气候强烈影响这些亚高山物种的冬季水分关系，并且在预测这些物种未来的分布范围时必须考虑夏季和冬季气候的变化。
