以不同林龄（幼龄、中龄、老龄）华北落叶松为研究对象，依托国家级森林生态系统定位观测站，连续5年采用热扩散式茎流计法（树木蒸腾）和称重法（土壤蒸发）对华北落叶松土壤蒸发与植被蒸散耗水及其环境因子进行定量监测，定量分析蒸腾、蒸发等各蒸散的强度与环境因子的关系。结果表明：2012-2017年不同林龄土壤蒸发量和蒸腾耗水量均呈“几”字形变化规律，在7-8月达到最大，4-6月呈急剧增加趋势，9月以后有所降低；当土壤含水量>18 %，地被植物并不抑制土壤水分的蒸发；当土壤含水量<18 %，地被植物抑制了土壤水分的蒸发；土壤蒸发量与土壤温度和土壤含水量均呈显著的正相关。相关性分析表明林木蒸腾强度与土壤含水量、太阳辐射强度、土壤温度呈正相关，也即华北落叶松林木蒸腾强度随各环境因子变量值的增加而增加；然而，林木蒸腾强度与自身属性（冠幅、胸径、株高）呈负相关关系，即随着林木的生长，其蒸腾作用受到了一定的抑制。综合分析表明：影响华北落叶松耗水最直接的因素是土壤水分含量，当土壤含水量较小时，华北落叶松首先满足自身对于土壤水分的需求。

Ｒelying on national forest ecosystem research station，Larix principis－rupprechtii in Qinling Mountains is taken as the study area in five years． In order to quantitatively reveal the levels of transpiration and evaporation intensity and their relationship with environmental factors，the Larix principis－rupprechtii plantations water consumption and related environmental factors are monitored in this region． Then the effects of vegetation structure on vegetation characteristics of water consumption are analyzed． The weighing method is used to measure the soil evaporation and thermal dissipation probe ( TDP) is used to measure the sap－flow dynamics． Combing with the investigation of environmental factors，the data are analyzed． The results show that soil evaporation and water consumption of Larix principis － rupprechtii plantations vegetation increase and then decrease，which are the highest in July and August，and then decrease． When the soil water content is above18%，the ground cover plants not inhibit soil moisture evaporation． Soil evaporation model shows that the soil evaporation is positively correlated with soil moisture content and temperature． Correlation analysis shows that Larix principis－rupprechtii plantations are positively related to the soil water content，the solar radiation intensity，soil temperature，namely forest transpiration intensity will be increased with the increase in the environmental factor variable values． However，the forest transpiration intensity and own properties ( crown breadth，diameter at breast height，plant height) shows a negative correlation，which is with the growth，forest transpiration will be suppressed． Overall，the main factor that affects forest water consumption is the soil moisture，if the soil water contents decrease，the forest vegetation will solve their demand for water in the first place．