中国旱区森林生态系统的林冠截留综述

A Review of Canopy Interception of Forest Ecosystems in Drylands of China

林冠截留作为森林水文过程中的重要组成部分,通过调整降雨的时空分布改变区域潜在可利用水量,影响森林生态系统服务。随着气候变化,林冠截留对不同气象条件的响应体现出较大的时空差异,同时由于中国旱区的植被恢复措施,该地区植被结构发生较大改变。然而当前针对中国旱区缺乏降雨再分配研究的系统归纳和整合分析,导致气候变化和人类活动影响下中国旱区林冠截留特征尚不明确。本文在综述当前林冠截留的概念、影响因素和量化方法的基础上,通过收集和分析2010-2024年间中国旱区森林降雨再分配的249条野外观测数据,研究发现中国旱区森林生态系统林冠截留占总降雨量的比重为0%~51.6%(平均值为24.4%),针叶林和混交林林冠截留占比的平均值大于阔叶林,分别为25.6%,25.5%和21.1%,林冠截留量随年降水量的增加呈显著的增加趋势,林分密度、林龄、胸径等林分结构特征是影响不同森林类型林冠截留占比的重要因素。本文揭示了中国旱区森林和灌木生态系统的降水再分配及林冠截留占比特征,阐明了森林生态系统林冠截留与气象条件和林分结构的关系。基于上述研究,建议明确中国旱区不同造林营林措施的林冠截留差异、加强旱区林冠截留对气候变化的响应研究、探索多时空尺度林冠截留的准确量化路径,以期为旱区植被恢复和水资源可持续利用提供科学支撑。

Canopy interception plays a crucial role in forest hydrological process,altering regional water availability and influencing the temporal and spatial distribution of rainfall,thereby affecting forest ecosystem services.With climate change,the response of canopy interception to varying meteorological condition has showed a large spatial-temporal heterogeneity.In addition,vegetation restoration measures have led to significant changes in vegetation structure in Chinas drylands.Despite these changes,systematic analyses of rainfall redistribution in drylands of China are lacking and further responses of forest canopy interception characteristics in this region to climate change and human activities remain unclear.This paper reviewed the prevailing concepts,influencing factors and quantitative methods of canopy interception.By analyzing 249 field observation data of forest rainfall redistribution in drylands of China during 2010-2024,we found that the ratio of canopy interception to corresponding gross rainfall in forest ecosystems ranged from 0%to 51.6%(with a mean value of 24.4%).The average canopy interception ratios in coniferous forests(25.6%)and mixed forests(25.5%)were higher than that in broad-leaved forests(21.1%).Canopy interception increased significantly with increasing in annual rainfall.The characteristics of forest structure including,stand density,stand age,and diameter at breast height were the most important factors affecting the canopy interception ratio among different forest types.Our review revealed rainfall redistribution and canopy interception characteristics of forest and shrub ecosystems in this region,and elucidated the relationship between forest canopy interception characteristics and meteorological conditions and forest structure.Therefore,it is suggested to clarify the discrepancies in canopy interception among various vegetation restoration and forest management measures in drylands of China,to enhance studies on the responses of canopy interception to climate change in drylands.Moreover,there is a critical need to develop the precise quantification methods for canopy interception across multiple spatio-temporal scales,so as to provide scientific support for the vegetation restoration and the sustainable utilization of water resources in drylands of China.