哈尔滨城市森林树木生长状况及各生长指标的相关性分析

目的]研究哈尔滨市城市森林树木生长状况及各生长指标的相关关系,为指导城市树木管理、优化城市森林结构提供理论依据。方法]在哈尔滨市建成区随机调查单位附属林、道路林、景观游憩林和生态公益林4种林分共220块样地,每块样地中分别取4~10株树木测量其树高、枝下高、冠幅和胸径周长等指标。结果]哈尔滨市城市森林树木树高小于10 m近70%左右,枝下高绝大部分小于4m,冠幅小于50 m2的占总量的69%,胸径周长小于100 cm的树木约占80%,冠幅和胸径周长虽存有较大树木(冠幅250~325 m~2、胸径周长200~250 cm),但数量不到所调查树木总量的5%,且冠幅大小分布较离散。树高、枝下高、冠幅、胸径周长平均值分别为8.57 m、2.20 m、47.93 m~2、66.30 cm。4种指标之间呈显著正相关(P0.05)。对比4种林分发现,生态公益林树木的树高较其他3种林型高3 m左右,胸径周长长20 cm左右,道路林的冠幅小于其他3种林分6~11 m~2。结论]哈尔滨市城市森林整体长势偏小,小冠幅树木居多,且林型间差别较大,今后应加强保护大树和抚育管理幼树。

Correlations Analysis of of Growth Index an d Growth Status of Urban Trees in Harbin City

Objective] To investigate the growth status of urban trees and their correlations of growth index in Harbin City to guide management of urban trees and optimize urban forest structure.Method] 220 sites of affiliated forest, roadside forest, landscape forest and ecological welfare forest throughout Harbin City were investigated.Tree height, lowest-branch height, canopy-projection area,and diameter at breast height (DBH) of 4-10 trees from each site were measured.Result] Nearly 70%of surveyed trees were less than 10 m in height, and the lowest-branch height of most measured trees was less than 4 m.The canopy area of 69% of surveyed trees was less than 50 m2 .The DBH of about 80% of surveyed trees was less than 100 cm.Although there were trees with a large canopy area (250-325 m2 ) and DBH (200-250 cm), the proportion of their number in the total quantity of surveyed trees was less than 5%.The averages of tree height, lowest-branch height, canopy area, and DBH were 8.57 m, 2.20 m, 47.93 m2, and 66.30 cm respectively.There were significantly positive correlations between the four indicators (P<0.05). Compared with the other three types of forest, the tree height of the ecological welfare forest was higher, about 3 m, and its DBH was larger, a-bout 20 cm.The canopy area of roadside forest was 6-11 m2 smaller than that of the other three types of forest.Conclusion] Most urban trees in Harbin City are small in general.The canopy area of most trees is small, and there is a big difference between the forest types.It is needed to pro-tect big trees and manage and tend young trees in future .