天目山常绿阔叶林空间结构与地形因子的关系

Relationship between spatial structure and terrain factors of evergreen broad-leaved forest in Mount Tianmu

【目的】研究天目山常绿阔叶林的空间结构与地形因子之间的关系,以期为常绿阔叶林的经营管理提供科学依据。【方法】以浙江省天目山国家级自然保护区常绿阔叶林为研究对象,设置100 m×100 m的大型固定样地,用相邻格子调查方法将样地划分为100个10 m×10 m的调查单元,对样地内林木进行实测。用聚集指数、竞争指数和树种多样性混交度描述空间结构特征,以坡度、坡向、海拔和粗糙度作为地形因子,利用方差分析分析空间结构与地形因子之间的关系。【结果】①坡度过大或过小都会导致竞争指数显著增大(P<0.05)。半阳坡的树种多样性混交度显著高于阳坡(P<0.05),Ⅰ级粗糙度的树种多样性混交度显著低于Ⅲ级粗糙度(P<0.05)。随着样地内海拔的升高,林分的树种多样性混交度显著增大(P<0.05),但样地内海拔过高或过低,都会使聚集指数显著减小(P<0.05)。②在Ⅲ级粗糙度中,Ⅰ级坡的竞争指数显著高于Ⅱ级坡和Ⅲ级坡(P<0.05),Ⅱ级坡的树种多样性混交度显著高于Ⅰ级坡和Ⅲ级坡(P<0.05),半阳坡的聚集指数和树种多样性混交度显著高于阳坡(P<0.05)。在样地内的高海拔区域,Ⅰ级坡的竞争指数显著高于Ⅱ级坡和Ⅲ级坡(P<0.05);而在样地内的中海拔区域,Ⅲ级粗糙度的聚集指数和树种多样性混交度显著高于Ⅰ级粗糙度和Ⅱ级粗糙度(P<0.05)。【结论】在常绿阔叶林群落中,不同的地形因子对其空间结构特征有着不同程度的影响。在一定地形条件下,合理调控常绿阔叶林的空间结构是促进树木生长的重要经营策略。

[Objective]The objective of this study is to explore the relationship between spatial structure and terrain factors of evergreen broad-leaved forest in Mount Tianmu,so as to provide scientific reference for the management of evergreen broad-leaved forest.[Method]Taking the evergreen broad-leaved forest in Mount Tianmu National Nature Reserve of Zhejiang Province as the research object,a large sample of 100 m×100 m was set up and divided into 100 grids of 10 m×10 m investigation units using the method of adjacent grid survey.The trees in the sample plot were measured.The aggregation index,competition index and mingling degree of tree species diversity were used to describe the spatial structure characteristics.Slope,aspect,altitude and roughness were used as terrain factors.The relationship between spatial structure and terrain factors was analyzed by analysis of variance.[Result](1)If the slope was too large or too small,the competition index increased significantly(P<0.05).The mingling degree of tree species diversity on the semi-sunny slope was significantly higher than that on the sunny slope(P<0.05),and that in classⅠroughness was significantly lower than that in classⅢroughness(P<0.05).With the increase of the altitude in the plot,the mingling degree of tree species diversity increased significantly(P<0.05),but the aggregation index decreased significantly(P<0.05)when the altitude was too high or too low.(2)In roughness of classⅢ,the competition index of classⅠslope was significantly higher than that of classⅡand classⅢ(P<0.05),the mingling degree of tree species diversity of classⅡslope was significantly higher than that of classⅠand classⅢ(P<0.05),and the aggregation index and the mingling degree of tree species diversity on the semi-sunny slope was significantly higher than those on the sunny slope(P<0.05).In the high altitude area of the plot,the competition index of classⅠslope was higher than that of classⅡand classⅢslope(P<0.05),while in the middle altitude area of the plot,the aggregation index and the mingling degree of tree species diversity of classⅢroughness were significantly higher than those of classⅠand classⅡroughness(P<0.05).[Conclusion]In evergreen broad-leaved forest community,different terrain factors have different effects on its spatial structure.It is an important management strategy to regulate the spatial structure of evergreen broad-leaved forest under certain terrain conditions.