六盘山不同坡向华北落叶松林分蒸腾对环境因子的响应  

Transpiration of Larix gmelinii var.principis-rupprechtii Plantations on Different Slope Aspects in Liupan Mountains in Response of Environmental Factors

作　　者：杨世纪 万艳芳 白雨诗 王冬梅[1] 于澎涛[2] 王彦辉[2] 王巍樾 陈瑜佳 Yang Shiji;Wan Yanfang;Bai Yushi;Wang Dongmei;Yu Pengtao;Wang Yanhui;Wang Weiyue;Chen Yujia(Collegel of Soil and Water Conservation,Beijing Forestry University,Key Laboratory of Soil and Water Conservation and Desertification Combating of Ministry of Education,Beijing 100083;Ecology and Nature Conservation Institute,CAF,Key Laboratory of Forestry Ecology and Environment of National Forestry and Grassland Administration,Beijing 100091)

机构地区：[1]北京林业大学水土保持学院、水土保持与荒漠化防治教育部重点实验室,北京100083 [2]中国林业科学研究院森林生态环境与自然保护研究所,国家林业和草原局森林生态环境重点实验室,北京100091

出　　处：《林业科学》2025年第3期108-120,共13页Scientia Silvae Sinicae

基　　金：“十四五”国家重点研发课题(2022YFF1300404);国家自然科学基金项目(U21A2005,U20A2085,42161144008)。

摘　　要：【目的】在作为我国黄土高原重要水源地宁夏六盘山的半干旱区,定量研究华北落叶松人工林蒸腾对气象条件、土壤水分、林冠结构的响应规律及其坡向差异,为该区域林水协调管理提供理论依据。【方法】2023年5—10月,在叠叠沟小流域西北坡NW50°、正北坡N0°、东北坡NE30°的典型坡面中部,各设置1块20m×20m华北落叶松人工林固定样地,连续监测树干液流密度、气象因子(表示为日潜在蒸散量PET)和0~60cm土层含水量(表示为相对土壤含水量REW),并定期监测林冠层叶面积指数(LAI),分析不同坡向林分蒸腾对PET、REW和LAI的响应。【结果】1)2023年生长季(5—10月),正北坡林分日均蒸腾量最大(0.93mm·d^(-1)),比西北坡(0.59mm·d^(-1))和东北坡(0.73 mm·d^(-1))分别高0.34、0.20 mm·d^(-1);在干旱期(REW<0.45)的林分蒸腾各坡向间较接近且差异不显著(P>0.05)。2)林分日蒸腾量随REW和LAI增加呈先快速上升后缓慢上升并渐趋稳定的变化,可用指数函数描述;随PET增加呈先快速上升后缓慢上升并在达到某峰值后略微下降的变化,可用二项式函数描述。3)林分日蒸腾量对PET的响应在非干旱期(REW>0.45)显著强于干旱期(REW<0.45),表现为林分蒸腾量随PET增加的增长速率在非干旱期大于干旱期,且阴坡林分的增长速率明显高于半阴坡林分;而干旱期林分蒸腾量受到土壤水分的限制,表现为林分蒸腾随REW增加呈快速增加趋势,且半阴坡的增长速率明显高于阴坡,即半阴坡林分蒸腾对土壤干旱的响应比阴坡林分更敏感。基于各因子对林分蒸腾影响的贡献率分析,发现REW是导致干旱期林分蒸腾差异的主导因素,平均贡献率为10.21%,且在半阴坡样地的抑制效果最明显(11.8%);在非干旱期,LAI是导致林分蒸腾差异的主导因素,偏离正北方向越大时LAI抑制林分蒸腾效果越弱。【结论】在持续土壤干旱期,华北落叶松林分蒸腾受到土�【Objective】This study aims to quantitatively study the transpiration of Larix gmelinii var.principis-rupprechtii plantations on different slope aspects in response of meteorological conditions,soil moisture,and forest canopy structure in the semi-arid area of Liupan Mountains in Ningxia,which is an important water source area on the Loess Plateau of China,so as to provide a theoretical basis for the integrated forest-water management in this region.【Method】From May to October 2023,a fixed plot of 20 m×20 m of L.gmelinii var.principis-rupprechtii plantation was set in the middle of typical slopes with different slope aspects(northwest slope NW50°,north slope N0°and northeast slope NE30°)in the small watershed of Diediegou.The sap flow density,meteorological parameters(represented by potential evapotranspiration,PET),and the soil water content of 0-60 cm soil layer(represented by the relatively extractable soil water,REW)were monitored continuously,and the canopy leaf area index(LAI)was regularly measured,to analyze the response of stand transpiration to PET,REW,and LAI.【Result】1)During the growing season(May to October)in 2023,the average daily transpiration of the stand on the north slope was the highest(0.93 mm·d^(-1)),-1 which was 0.34 and 0.2 mm·d higher than that on the northwest slope(0.59 mm·d^(-1))and on the northeast slope(0.73 mm·d^(-1)),respectively.During the soil drought period(REW<0.45),the stand transpiration rates on different slopes were close with each other and showed no significantly difference(P>0.05).2)The daily stand transpiration rapidly increased first and then slowed down and gradually stabilized with rising REW and LAI,with an exponential function,while the daily transpiration rapidly increased first and then slowly increased and then decreased slightly after a certain peak with rising PET,with a binomial function.3)The response of daily transpiration to PET was significantly stronger during non-drought periods(REW>0.45)than that during drought periods(REW<0.45),showi

关 键 词：华北落叶松 林分蒸腾 坡向 干旱 土壤水分 潜在蒸散 

分 类 号：S715[农业科学—林学]