Inter-specific differences in water use and environmental response of three potential evergreen tree species in south subtropical China
[Objective]This study aimed to explore the inter-specific differences in water use among potential green tree species including Schima superba,Castanopsis chinensis,and Pinus massoniana in the southern subtropical mixed forest community,in conjunction with meteorological conditions and tree physiological characteristics.Understanding their adaptation mechanisms under complex environmental changes could optimize tree resource allocation in greening applications and promote sustainable ecological development.[Method]The changes in stem sap flow of S.superba,C.chinensis,and P.massoniana were monitored using the Granier heat dissipation probe method.Environmental factors such as temperature,humidity,photosynthetically active radiation,air pressure deficit,and soil water content were analyzed.[Result]During both dry and wet seasons,S.superba,C.chinensis,and P.massoniana exhibited a unimodal curve of"high in day and low in night"for sap flow.In the dry season,significant differences were observed in the average daily sap flow rates among the three species.Specifically,C.chinensis demonstrated the highest average daily sap flow density,reaching 11.84±1.13 g·m-2·s-1,while S.superba and P.massoniana exhibited relatively lower densities of 7.81±0.74 and 8.71±1.64 g·m-2·s-1,respectively.In the wet season,overall sap flow rates increased,with S.superba and C.chinensis maintaining higher rates with average daily densities of 9.41±4.74 and 12.05±5.18 g·m-2·s-1,respectively,while P.massoniana exhibited a lower average daily density of 6.59±3.24 g·m-2·s-1.Photosynthetically active radiation and vapor pressure deficit were identified as key factors driving sap flow.As photosynthetically active radiation and vapor pressure deficit increased,sap flow rates of all three species showed an upward trend,but growth rates slowed noticeably once photosynthetically active radiation and vapor pressure deficit reached certain thresholds.Soil water content had a relatively low impact on sap flow rates.[Conclusion]Among the three greening tree species,P.massoniana exhibits relatively lower sap flow density,while S.superba and C.chinensis have higher sap flow densities.During extreme weather conditions,P.massoniana demonstrates greater resilience to drought compared to broad-leaved tree species.In future urban greening projects,it is imperative to fully consider the water utilization characteristics of different tree species and make rational combinations in order to achieve the objectives of water conservation and greening.
SAP flowwater useenvironmental factorslandscaping tree species
万方数据
维普
