芦芽山不同海拔华北落叶松径向生长与气候因子关系的研究

LARIX PRINCIPIS-RUPPRECHTII'S RADIAL GROWTH-CLIMATE RELATIONSHIP AT DIFFERENT ELEVATIONS IN LUYA MOUNTAINS

利用采自山西芦芽山3个海拔高度的华北落叶松(Larix principis-ruppre chtii)年轮样芯建立差值年表,通过与气候因子的相关性分析,以及单年分析和多元回归的方法,探讨树木径向生长与气候因子的关系,发现各个海拔高度的华北落叶松径向生长均受到气温、降水因子的综合影响,且与降水因子的关系均较与气温因子的关系密切.机制上,生长季中低海拔华北落叶松径向生长受到土壤干旱的限制,而高海拔华北落叶松受到低温的限制.随海拔升高,华北落叶松径向生长与生长季降水因子的关系从正相关逆转为负相关.在本次研究设立的低海拔(1 972 m)与中海拔(2 237 m)采样点之间,生长季降水量增加从而跨越了其对华北落叶松生长限制的阈值.

Tree cores of Larix principis-rupprechtii were taken from 3 sites at different elevations to stand for the trees＇ growth in Luya mountains, correlation analysis, single year analysis and multiple regression method were carried on to correlate growth-climate relationship. Data showed that temperature and precipitation factors combined impact radial growth at each elevation; influence of precipitation factors on growth was found to be stronger than temperature factors. In growing season, tree radial growth was limited by soil drought at low elevation, but by low temperature at high elevation. In growing season, the positive correlationship was reversed to negative between tree radial growth and precipitation factors with increasing elevation. With elevation climbing from 1 972 to 2 237 m, precipitation in growing season increased sharply, eventually surpassing limitation precipitation threshold.