祁连山中部青海云杉年内径向生长季节变化及其对环境因子的响应

Seasonal Variation of Annual Radial Growth of Picea crassifolia and Its Response to Environmental Factors in the Central Qilian Mountains

以祁连山中段排露沟小流域青海云杉为研究对象,2018年5—10月应用带状树木径向生长记录仪对4株青海云杉径向生长过程进行测定,并同步测定气象因子和土壤温度、湿度,分析单株青海云杉径向生长的季节变化特征及其树木个体之间的差异,确定青海云杉在不同生长阶段的限制因子。结果表明:(1)4株青海云杉6月8日左右开始生长,7月28日左右结束生长,生长期约51天。(2)青海云杉径向生长季节变化特征在个体之间存在差异,胸径较小的树木(DBH=10.0 cm和11.0 cm),生长启动晚,结束早,生长期短,年累积生长量少,而胸径较大的树木(DBH=18.3 cm和21.0 cm)正好相反,生长期长,年累积生长量多。(3)青海云杉径向生长具有明显的季节变化模式,分为3个阶段,分别为启动生长阶段(5—6月初)、快速生长阶段(6月初至7月末)和结束生长阶段(8—10月),平均生长速率分别为0.35,12.99,0.54μm/d。(4)青海云杉在不同的生长阶段限制因子不同,其中,启动生长阶段,降雨和土壤温度是限制生长的主要因子;快速生长阶段,降雨和土壤体积含水量是主要因子。因此,从整个生长季来看,土壤温度和水分是影响青海云杉年内径向生长的主要因子。

Took Qinghai spruce(Picea crassifolia)in the small watershed of Pailugou in the central Qilian Mountains as the research object.From May to October 2018,the radial growth process of four strains of Qinghai spruce was measured using the belt tree radial growth recorder,and the meteorological factors were simultaneously measured.Based on the soil temperature and humidity,the seasonal variation characteristics of the radial growth of individual Qinghai spruce and the differences between trees were analyzed,and the limiting factors of Qinghai spruce in different growth stages were also determined.The results showed that:(1)The four Qinghai spruce plants began to grow on June 8 and ended on July 28,with a growth period of about 51 days.(2)The characteristics of the radial growth season of Qinghai spruce were different among individuals.The growth of trees with smaller DBH(DBH=10.0 cm and 11.0 cm)started later and ended earlier,resulting in the shorter growing period and less annual cumulative growth,while trees with larger DBH(DBH=18.3 cm and 21.0 cm)gave an opposite results,with a longer growing period and more annual cumulative growth.(3)The radial growth of Qinghai spruce had an obvious seasonal change pattern,which was divided into three stages:the initial growth stage(May to early June),the rapid growth stage(early June to late July)and the end growth stage(August to October)with the average growth rates of 0.35μm/d,12.99μm/d and 0.54μm/d respectively.(4)The limiting factors of Qinghai spruce growth were different among different growth stages:in the initial growth stage,rainfall and soil temperature were the main factors restricting growth,and during the rapid growth stage,rainfall and soil volumetric water content were the main factors.Therefore,from the perspective of the entire growing season,soil temperature and moisture were the main factors affecting the annual radial growth of Qinghai spruce.