Predicting variations of evapotranspiration, photosynthesis and water use efficiency in a forest with the change in LAI by the forest management

通过森林管理预测森林蒸散量、光合作用和水分利用效率随 LAI 变化的变化

基本信息

批准号：
15600002
负责人：
OUE Hiroki
金额：
$ 2.43万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

1.Observations in the fieldThe following observations were made at the micrometeorological observational tower, around the center of a coniferous forest catchment that was mainly planted with Japanese cedar and the area of which was 10.7 ha in Ozu.(1)Observation of fluxes by the eddy correlation method and Bowen ratio energy budget method(2)Transpiration and photosynthesis of a single leaf(3)Soil respiration(4)Water balance of the catchment2.ResultsVariations of daily evapotranspiration (ET) and CO_2 flux (CER) in 2005 reached maximum in May - September with minimum in winter. Correlation coefficients between these two fluxes and meteorological conditions, soil water content and four seasons revealed that solar radiation was the first and air temperature was the second factor influencing on the two fluxes. The significance test revealed that the difference between two groups of the fluxes under the condition of air temperature higher than 22 C and lower than 22 C was significant. Yearly ET was 1000 mm and absorption of CO_2 was 27.9t/ha in the forest catchment in 2005.The LAI measured was 4.93 at the observational site. By using a simple model of the canopy transpiration and photosynthesis that consists of leaf transpiration and photosynthesis model and multilayer radiation model within the canopy, variations of canopy ET and photosynthesis with the change in LAI were modeled. The predicted LAI that would make the water use efficiency highest was around 4.

1.在田间的观察，在微量标学观察塔上进行了以下观察结果，该塔的中心是在针叶林集水区的中心，主要用日本雪松种植，其区域在Ozu中为10.7公顷。（1）通过涡流相关方法和弓形预算方法（2）透明的杂物（2）透明效率（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）浮雕（2）流域2. 2005年每日蒸散量（ET）和CO_2通量（CER）的重新变量在5月至9月达到最大值，冬季最少。这两个通量与气象条件，土壤水分含量和四个季节之间的相关系数表明，太阳辐射是第一个，空气温度是影响这两个通量的第二个因素。显着性测试表明，在空气温度的条件下，两组通量之间的差异高于22 c，低于22 C的差异很显着。每年的ET为1000毫米，2005年森林流域的CO_2的吸收为27.9t/ha。在观测部位测得的LAI为4.93。通过使用冠层蒸腾和光合作用的简单模型，该模型包括叶片蒸腾和光合作用模型和冠层内的多层辐射模型，Canopy ET和光合作用的变化与LAI的变化进行了建模。预计将使用水效率最高的LAI约为4。