新疆山地针叶林乔木胸径-树高关系分析

Study on Relationship between Height and DBH of Mountain Coniferous Forests in Xinjiang

树木的生长包括了径向生长和垂直生长两个方面,这两方面具有密切的关系,这一关系既受到树木本身的控制,同时也受森林立地条件的影响。通过分析新疆阿尔泰山、天山南北坡以及昆仑山区11个地点120个样方的胸径-树高关系。结果表明:昆仑山的尖削度(taper)显著大于其余3地,其潜在最大树高(potential height,H*)显著小于阿尔泰山和天山北坡。随着海拔的升高,针叶林尖削度显著上升,潜在最大树高显著下降;随年降水的增加,尖削度显著减小,而潜在最大树高显著增加。一般线性模型(generall inearmodel,GLM)分析表明,尖削度和潜在最大树高受年降水、坡向和林型等因素影响较大,而受年平均气温的影响较小,说明新疆山区针叶林胸径-树高关系主要受水分的影响,即水分是生产力的限制因素。胸径-树高与气候的关系具有区域分异,在北疆,尖削度受坡向、坡位和年平均气温的影响较大,而受年降水的影响较小;在南疆,尖削度主要受年降水和坡向的影响,其次是年平均气温。

Growth of trees includes two dimensions,i.e. diameter and height. The height-diameter relationship is affected by climatic and topographic conditions as well as species properties. In this paper,the relationship between stem diameter at breast height （DBH） and stem height （H） of coniferous forests is analyzed based on 120 sample plots investigated from 11 locations in the Altay Mountains （Altay）,Kunlun Mountains （KL in abbreviation,the same below）,and northern and southern slopes of the Tianshan Mountains （NT and ST respectively） in Xinjiang. The potential heights （H＊） of trees in each plot were estimated. The results show that the taper of coniferous forests in KL,calculated with DBH/H,is higher than that in other regions,and the potential height in KL is lower than that in Altay and NT. For different forests,the taper of Pinus sibirica,Abies sibirica and Picea obovata forests is lower than that of Larix sibirica and Juniperus forests. The taper of Picea schrenkiana forests is lower than that of Juniperus forests but higher than that of Picea obovata forests. The H＊ of Juniperus forests is lower than that of other forests. Taper increases with the increase of altitude but decreases with the increase of AP in whole Xinjiang. For different regions,taper increases but H＊ decreases with the increase of altitude in Altay and NT,but there is no notable change of taper and H＊ with the increase of altitude in ST and KL. For different forests,the taper and H＊ of L. sibirica and Picea schrenkiana forests increase and decrease significantly with the increase of altitude separately. The taper of Pinus sibirica and A. sibirica forests increases significantly with the increase of altitude. According to the GLM （General Linear Model） analysis,change of the height-diameter relationship with environmental factors is different from different regions and scales. Annual precipitation （AP）,aspect of sample plots （ASP） and forest type are the most important variables to taper and H＊ in whole Xinjiang. ASP,slope position （POS） and mean annual temperature （MAT） are important in north Xinjiang,and ASP,AP and MAT are important in south Xinjiang.