北京市居住区林木健康评价

Health Assessment of trees in residential areas of Beijing

为了揭示北京市居住区林木健康变化特征及影响因素,提供北京市居住区林木健康经营对策。对北京市85个居住区林木进行健康特征调查,在建立林木健康评价模型评价林木健康状况的基础上,采用方差分析法和多重比较法分析不同类型居住区林木健康差异。结果表明:不同类型居住区林木健康指标差异显著(P<0.05),各指标变化规律不完全一致;不同类型居住区地表覆盖情况、光污染程度、树干倾斜度、栽植截干、树势、冠形、干形等方面普遍较差。北京市居住区林木健康指数在0.60—0.80之间,健康等级呈现右偏正态分布特点,健康林木比例为3.65%,亚健康林木(56.07%)最多,其次是中等健康林木(36.68%),不健康林木有3.50%,濒死林木仅占0.10%。居住区林木健康指数在不同区域和不同来源间差异不显著(P>0.05),在不同时期间差异显著(P<0.05),健康指数大小分别为:三—四环=四—五环>五—六环>二环内=二—三环;福利房>商品房>保障房;2009—2013年>2003—2008年=1998—2002年=1991—1997年>1956—1990年。北京市居住区林木生长处于亚健康状态,潜在影响因子如地表覆盖情况、光污染程度、树干倾斜度等指标是限制北京市居住区林木生长的重要因子。适当减小夜间照明影响、增加有机地表覆盖、避免过度的修枝截干和加强林木养护管理是当前北京市居住区林木健康生长的保障。

In this study,we aimed to identify the variations and factors determining tree health in residential areas of Beijing,and provide recommendations to tree health managements,by investigating 85 residential areas in Beijing.Tree health was evaluated using a tree health assessment model,and on the basis of this,differences in tree health among different types of residential areas were assessed using one-way ANOVA and the Duncan test.The results were as follows:tree health indicators were significantly different in different types of residential areas(P<0.05),and the variation ranks of each indicator were not completely consistent.Some tree health indicators in some types of residential area were generally poor,and factors determining this were surface coverage,light pollution,trunk lean,cutting off crown and planting,tree vigor,crown profile and stem form.Trees health indices in all residential areas of Beijing tested were 0.60—0.80,and tree health was characteristic of a right normal distribution.Healthy trees accounted for 3.65%,sub-healthy trees accounted for 56.07%,medium-healthy trees accounted for 36.68%,unhealthy trees accounted for 3.50%,and dying trees accounted for 0.10%.Tree health indices were not significantly different(P>0.05)between residential areas in different districts and origins,while differences between different assessment periods were significant(P<0.05).Ranks of trees health indices in difference types of residential area are presented:3rd—4th ring road=4th—5th ring road>5th—6th ring road>within 2nd ring road=2nd—3rd ring road;welfare housing>commodity apartment>social security housing;2009—2013>2003—2008=1998—2002=1991—1997>1956—1990.The majority of trees in residential areas of Beijing are in a sub-healthy state,and potential factors such as surface coverage,light pollution,and trunk lean are important factors restricting tree growth.Reducing the influence of night lighting,increasing the coverage of organic ground surfaces,avoiding excessive pruning of branches,and improving maintenance and management of trees will ensure healthy growth of trees in the residential areas of Beijing.