Assessing the Impact of Soil Moisture on Canopy Transpiration Using a Modified Jarvis-Stewart Model

In dryland regions, soil moisture is an important limiting factor for canopy transpiration (T). Thus, clarifying the impact of on T critical comprehensive forest—water management and sustainable development. this study, T, meteorological factors (reference evapotranspiration, ETref), (relative water content, RSWC), leaf area index (LAI) in a Larix principis-rupprechtii plantation Liupan Mountains region Northwest China were simultaneously monitored during growing seasons 2017–2019. A modified Jarvis—Stewart model was established by introducing RSWC different layers (0–20, 20–40, 40–60 cm, respectively) to quantify independent contribution T. Results showed that with rising ETref, firstly increased then decreased, LAI, gradually stabilised, respectively. The able give comparable estimates those derived from sap flow measurements. has obvious specificity, rate 20–40 cm (13.4%) 0–20 (6.6%) where roots are mainly distributed significantly higher than layer (1.9%). As status changes moist (RSWC0–60cm ≥ 0.4) drought < 0.4), role compared other layers. impacts coupled into can genuinely reflect environmental influence be used contributions it potential become new tool guide protection forest resources.