北京城市公园人工林生态系统水分利用效率的季节变化  

Seasonal Variations in Water Use Efficiency of Plantation Ecosystem in an Urban Park of Beijing

作　　者：谢静 张峰 周泽圆 于海群 韩艺 杨春欣 蒋薇 刘进祖 刘博恩 刘鹤[2] Xie Jing;Zhang Feng;Zhou Zeyuan;Yu Haiqun;Han Yi;Yang Chunxin;Jiang Wei;Liu Jinzu;Liu Boen;Liu He(Beijing Forestry and Parks Planning and Resource Monitoring Center(Beijing Forestry Carbon and International Cooperation Affairs Center),Beijing 101118;Beijing Forestry University,Beijing 100083)

机构地区：[1]北京市园林绿化规划和资源监测中心(北京市林业碳汇与国际合作事务中心),北京101118 [2]北京林业大学,北京100083

出　　处：《林业科学》2024年第9期12-17,共6页Scientia Silvae Sinicae

基　　金：中国博士后科学基金面上基金一等资助(2013M540055)。

摘　　要：【目的】干旱、半干旱环境中人工林生态系统碳吸收与水分损失之间的平衡关系尚不明确,阐明森林生态系统水分利用效率(WUE)应对环境因子的响应机制有助于量化城市人工林碳、水通量的平衡关系。【方法】应用涡度协方差技术,结合微气象观测系统,获取北京奥林匹克森林公园内油松人工林生态系统碳、水通量和环境因子数据,运用统计和模拟方法,分析人工林碳、水通量在季节尺度的平衡关系以及在干旱、半干旱环境条件下碳吸收与水分损失之间的平衡关系。【结果】研究期2012—2014年降水少,均发生季节性土壤干旱情况,年降水量低于过去60年均值,且逐年降低,2014年降水总量仅271 mm。WUE年均值为2.2~2.9 g·kg^(-1),2012年最小(2.2 g·kg^(-1))、2013年最大(2.9 g·kg^(-1))。生长季WUE主要受植被指数(NDVI)、净辐射(Rn)、气温(Ta)、土壤水分含量(SWC)和饱和水汽压差(VPD)的影响。在季节尺度,调控WUE的主要环境因子有所不同,春季NDVI的影响最大(P<0.05),可解释春季WUE变异的48%;夏季Rn和Ta的影响较强(P<0.05),可分别解释夏季WUE变异的52%和57%;秋季SWC和VPD的影响较强(P<0.05),可分别解释秋季WUE变异的44%和54%。在生长季,WUE和Ta呈线性负相关(P<0.01),WUE与VPD和R_n呈非线性负相关(对数曲线关系),WUE与SWC呈线性正相关(P<0.01);然而在极端干旱月份,如2014年5、6和8月,WUE与SWC呈负相关(P<0.01),WUE降至最低。2012和2013年7月均出现连续无雨的干旱期,WUE达最低值3.7 g·kg^(-1)。相较而言,在生长季的连续降水期,随着SWC增加,WUE达最大值10.3 g·kg^(-1)。【结论】干旱、半干旱环境中人工林生态系统碳、水通量是相互耦合的,季节性干旱和炎热降低碳吸收量和水分损失量,导致WUE降低。生长季的干旱期,在Ta较高的环境下,随着SWC降低,WUE降至最低。在生长季不同气温条件影响下,人工林可利用的土壤有效水与干旱【Objective】The balance relationship between carbon absorption and water loss of plantation ecosystems under the arid and semi-arid environment conditions is poorly understood.The understanding of response mechanism of forest ecosystem water use efficiency(WUE)to environmental factors is useful for quantifying carbon and water balance of urban artificial forests.【Method】Eddy covariance technology combined with micrometeorological sensors were used to monitor ecosystem carbon and water fluxes and environmental factors of Pinus tabuliformis plantation of Beijing Olympic Forest Park for years 2012—2014,and statistical and simulation methods were used to analyze balance relationship between carbon and water fluxes in plantation ecosystems at the seasonal scale.【Result】All 3 years were dry years with little precipitation during the study period,resulting in seasonal soil drought.Annual precipitation values were all lower than the average of the past 60 years and decreased year by year,with total precipitation in year 2014 being only 271 mm.Annual WUE value were 2.2-2.9 g·kg^(-1),with the lowest value being 2.2 g·kg^(-1)in 2012 and the highest value being 2.9 g·kg^(-1)in 2013.During the growing season,WUE was mainly influenced by vegetation index(NDVI),net radiation(Rn),temperature(Ta),soil moisture content(SWC),and saturated vapor pressure difference(VPD).Main environmental factors of seasonal WUE were changing as the following patterns.In spring,NDVI had the greatest impact on seasonal WUE,which explained 48%of spring variations in WUE(P<0.05);in summer,the influence of Rn and Ta had the greatest impacts on seasonal WUE,which explained 52%and 57%of summer variations in WUE,respectively(P<0.05);and in autumn,the influence of SWC and VPD had the greatest impacts on seasonal WUE,which explained 44%and 54%of autumn variations in WUE,respectively(P<0.05).During the growing season,WUE and Ta showed a linear negative correlation(P<0.01);WUE showed a non-linear negative correlation(i.e.,logarithmic curve rela

关 键 词：生态系统水分利用效率 碳、水通量 干旱 人工林 

分 类 号：S716[农业科学—林学] P414[天文地球—大气科学及气象学]