Observation and Simulation of Sap Flux Densities for Three Tree Species in the Humid Region of China

IF 2.1 3区环境科学与生态学 Q2 ECOLOGY

Ecohydrology Pub Date : 2025-08-17 DOI:10.1002/eco.70097

Yishan Li, Lei Cheng, Quan Zhang, Lu Zhang

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引用次数: 0

Abstract

Tree transpiration plays an important role in the hydrological cycle and largely determines the availability of watershed water resources. The Hanjiang River Basin is the source of the middle route of the south-to-north water diversion project; understanding the characteristics of tree transpiration in the basin and its key controlling factors is of great importance for sustainable water resources management of the region. In this study, we measured the sap flux density as a surrogate of transpiration for three representative tree species (oak, poplar and pine) from January 2021 to December 2023 in the Hanjiang River Basin. Results showed that incoming short-wave radiation (Rsi) and vapour pressure deficit (VPD) are the major factors controlling daytime sap flux density. The nighttime sap flux density generally correlates with the daytime sap flux density for all the tree species. A statistical model was developed for estimating daytime sap flux density based on Rsi and VPD, and the nighttime sap flux density is estimated using its dependence on daytime sap flux density. The proposed model could explain more than 85% of sap flux density variation of the three tree species. Soil water content (SWC) exhibited different impacts on sap flux density among the three tree species, with oak and pine showing clear SWC control, while poplar showed negligible SWC control. Incorporating SWC in the proposed statistical model improved the model performance for oak and pine during dry periods. This study revealed the characteristics of sap flux density of oak, pine and poplar in the Hanjiang River Basin and proposed a statistical sap flux density model for sap flux density simulations in the humid region of China.

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中国湿润地区3种树种树液通量密度的观测与模拟

树木蒸腾在水循环中起着重要作用，在很大程度上决定了流域水资源的可利用性。汉江流域是南水北调中线工程的源头；了解流域树木蒸腾特征及其关键控制因素，对区域水资源可持续管理具有重要意义。本研究以2021年1月至2023年12月汉江流域3种代表性树种（橡树、杨树和松树）为研究对象，测量了树液通量密度对蒸腾的影响。结果表明，入射短波辐射（Rsi）和水汽压差（VPD）是控制白天树液通量密度的主要因素。所有树种的夜间树液通量密度与白天树液通量密度基本相关。基于Rsi和VPD建立了估算白天树液通量密度的统计模型，并利用其对白天树液通量密度的依赖来估算夜间树液通量密度。该模型可以解释三种树种超过85%的树液通量密度变化。土壤含水量对树液通量密度的影响在3种树种中表现出不同程度的差异，其中橡树和松树对土壤含水量的影响明显，而杨树对土壤含水量的影响则可以忽略不计。在提出的统计模型中加入SWC，提高了橡树和松木在干旱期的模型性能。本研究揭示了汉江流域栎、松和杨树树液通量密度的特征，提出了中国湿润地区树液通量密度模拟的统计模型。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ecohydrology 环境科学-生态学

CiteScore

5.10

自引率

7.70%

发文量

116

审稿时长

24 months

期刊介绍： Ecohydrology is an international journal publishing original scientific and review papers that aim to improve understanding of processes at the interface between ecology and hydrology and associated applications related to environmental management. Ecohydrology seeks to increase interdisciplinary insights by placing particular emphasis on interactions and associated feedbacks in both space and time between ecological systems and the hydrological cycle. Research contributions are solicited from disciplines focusing on the physical, ecological, biological, biogeochemical, geomorphological, drainage basin, mathematical and methodological aspects of ecohydrology. Research in both terrestrial and aquatic systems is of interest provided it explicitly links ecological systems and the hydrologic cycle; research such as aquatic ecological, channel engineering, or ecological or hydrological modelling is less appropriate for the journal unless it specifically addresses the criteria above. Manuscripts describing individual case studies are of interest in cases where broader insights are discussed beyond site- and species-specific results.