摘要
利用树木径向生长仪研究了黄土丘陵区6年生油松(Pinus tabulaef ormis)、山杨(Populus davidiana)和辽东栎(Quercus liaotungensis)及林下灌木胡颓子(Elaegnus umbellata)4种林木整个生长季茎干的径向变化,发现4种林木的径向变化表现为膨胀收缩旋回增长的模式。在整个生长季中,山杨从5月到10月径向持续增长,增长时间最长;而油松和胡颓子的径向生长主要发生在7月份,从8月份开始其增长速率变缓;辽东栎在整个生长季节的径向生长最小。在整个生长季内,山杨径向增长了2.63 mm,胡颓子为0.64 mm,油松和辽东栎则分别为0.40 mm和0.26 mm。辽东栎日收缩量与膨胀量明显大于其他树种。通过对影响林木径向生长的15种环境因子进行主成分分析后,将主要环境因子归结为温度影响因子、湿度影响因子和降水影响因子3个主成分,并提取了影响该区几种林木生长的主要环境因子:日大于0℃的积温、最低6 h相对湿度和日降雨量。采用线性逐步回归方法,建立了日膨胀量与日收缩量与3个主要环境因子之间的关系。发现日收缩量与日大于0℃的积温成正相关,而与最低6 h相对湿度和日降雨量均呈负相关关系;而日膨胀量亦与日大于0℃的积温成正相关,而与其他环境因子的关系随着树种的不同而不同,表现出较大的变异性。
The radial changes of tree stems of 6-year-grown Pinus tabulaeformis,Elaegnus umbellata,Populus davidiana and Quercus liaotungensis in the loess hilly region were researched by dendrometer.The seasonal growth of stems was a gradual increase accompanying with diurnal shrinkage and swelling.During the whole growing season,Populus davidiana continuously grew till October and had the longest growth period.The growth stage of Pinus tabulaeformis and Elaegnus umbellata was mainly in July of a year,and the growth rate began to decrease from August.The growth of Quercus liaotungensis stem was the least.The radial growth from May to October for Populus davidiana was 2.63 mm, 0.64 mm for Elaegnus umbellate,0.40 mm for Pinus tabulaeformis,and 0.26 mm for Quercus liaotungensis,respectively.The major factors affecting stem radial growth were summarized as temperature,humidity and precipitation through principal component analysis on 15 environmental factors.Stepwise linear regression was used to describe the relationship between daily shrinkage and swelling and specified environmental factors.Daily shrinkage was positively related with 〉 0℃ accumulative temperature and negatively related with the least relative humidity during 6 hours and daily precipitation. The daily expansion was also positively related with 〉0℃ accumulative temperature,but the association with other factors varied across the tree species.
出处
《水土保持学报》
CSCD
北大核心
2007年第6期170-173,196,共5页
Journal of Soil and Water Conservation
基金
国家自然科学基金重点项目(30230290)
国家"973"项目(2002CB111502)
关键词
树木径向生长
日变化
环境因子
radial growth of tree stem
diurnal change
environmental factors
