海南西部桉树人工林生长特征及其对气候环境的响应

在海南西部儋州林场选取空间相邻、自然条件相似、不同林龄序列的桉树人工林作为研究样地,通过定点系统监测,分析不同林龄桉树人工林生长变化特征及其对气候环境的响应。结果表明:1)桉树人工林胸径4—7月增长较快,7—10月增长最快,其它月份明显减缓。2)1—3a桉树人工林平均单株材积和单位面积材积年内增加幅度逐渐增加,3a达到最大值,4a较大,5a增长明显减缓。3)林龄显著地影响单株桉树生长,其中3a影响最大;土壤水分、降水极显著影响桉树生长,而气温对单株生长量影响不显著。4)土壤水分随林龄增加而减少,较低土壤水分对桉树人工林生长产生干旱胁迫作用,致使桉树单株材积增加减少,尤其是5a桉树人工林材积增加量减少最为明显。

Growth Characteristics of Eucalyptus Plantation and Their Responses to Climate Environment in Western Hainan Island

We selected 1-to-5-year old short-rotation Eucalyptus forests consisting of even-aged stand as sampling plots with adjacent space and similar natural conditions in Danzhou Forest Farm,which lies in west Hainan Island.Through continuous monitoring in the fixed sites,we analyzed the growth characteristics of different aged Eucalyptus plantations and their responses to climate environment.The results show that:1)The diameter at breast height of Eucalyptus plantation grew rapidly from mid April to mid July,fastest from mid July to mid October,and slowed down significantly in other months.2)Average volume increments of a single Eucalyptus tree and per hectare of Eucalyptus plantation increased from 1-to-3-year old.After the age of 3,the volume increments of 4 and 5 year old Eucalyptus forest slowed down,particularly the 5 year old Eucalyptus tree.3)The age of Eucalyptus affected its growth significantly,and there was the biggest influence in the third year.Both the precipitation and the soil water had significant correlations with individual Eucalyptus growth;however,the correlation between the temperature and the growth of individual Eucalyptus was not significant.4)Lower soil water was one of major abiotic stresses that caused the decrease of average individual volume increment of Eucalyptus forest,and the decrease was especially obvious of 5 year old Eucalyptus tree.