寒温带多年冻土区白桦树干液流及对降雨的响应  

Sap flow of Betula platyphylla and its response to rainfall in permafrost areas of the cold temperate zone

作　　者：尚友贤 满秀玲[1] 徐志鹏 SHANG Youxian;MAN Xiuling;XU Zhipeng(College of Forestry,Northeast Forestry University,Harbin 150040,Heilongjiang,China)

机构地区：[1]东北林业大学林学院,黑龙江哈尔滨150040

出　　处：《中南林业科技大学学报》2023年第6期125-136,共12页Journal of Central South University of Forestry & Technology

基　　金：国家重点研发计划项目(2021YFD2200405)。

摘　　要：【目的】为研究寒温带白桦树干液流对降水的响应,对不同降雨等级下的树干液流特征进行分析探究,为大兴安岭地区白桦用水策略以及管理提供依据和参考。【方法】2021年5—9月运用热扩散式探针法对寒温带白桦树干液流进行监测并同步观测气象因子和降水量。【结果】白桦树干液流在无雨天气下呈单峰形平滑曲线,峰值较高,优势木的峰值高达17.30 g·cm^(-2)·h^(-1),为中等木和被压木的1.18和2.48倍,而降雨天气下液流呈单峰或双峰形波动曲线,变化幅度相对比较平缓。相较于无雨日,3个降雨等级下的优势木日均液流均出现显著下降(P<0.05),在小雨、中雨以及大雨等级下,优势木日均液流量减少了43.02%、71.36%和56.27%,中等木液流分别减少了38.04%、48.79%和41.97%,被压木减少值依次为39.74%、59.42%和58.54%。此外,降雨前后的液流总体表现为叶盛期>展叶期>落叶期,在展叶期,降雨后的液流明显高于降雨前(P<0.05),优势木、中等木和被压木雨后液流在叶盛期变化不显著(P>0.05),落叶期优势木和中等木的雨后液流呈下降趋势(P<0.05)。相关性分析和逐步回归分析结果表明,在无雨日和降雨日,白桦树干液流均与空气温度、太阳有效辐射以及蒸气压亏缺呈正相关关系,与相对湿度呈负相关关系。小雨等级下,白桦液流变化主要取决于空气温度和蒸气压亏缺;中雨等级下,白桦液流变化主要受空气温度、相对湿度以及蒸气压亏缺的影响;大雨等级下,液流变化主要由太阳有效辐射和空气温度所驱动。【结论】降雨明显改变了不同分化等级白桦液流变化趋势及其对气象因子的响应,影响程度因降雨等级而异。【Objective】The objective of this study was to explore the response of sap flow of Betula platyphylla to precipitation in the cold temperate zone.The characteristics of the sap flow under different rainfall levels were analyzed,to provide theoretical references for the water use strategy and management of Betula platyphylla in the Daxing’an Mountain regions.【Method】From May to September 2021,the sap flow of Betula platyphylla was measured by the thermal diffusion probe method.Furthermore,the change in meteorological factors and precipitation was monitored simultaneously.【Result】The sap flow of Betula platyphylla exhibited a single-peak curve with a high peak value,which was smooth on non-rainy days.The sap flow value of dominant trees was 17.30 g·cm^(-2)·h^(-1),which was 1.18 times and 2.48 times those of the intermediate trees and suppressed trees,respectively,while the sap flow showed a fluctuation curve with unimodal or bimodal peaks in rainy days,and the variation was relatively gentle.Compared with non-rainy days,the average daily sap flow of dominant trees under the three rainfall levels was significantly decreased(P<0.05).Specifically,the average daily sap flow of dominant trees decreased by 43.02%,71.36%and 39.88%under light,moderate and heavy rainfall conditions,respectively.The average daily sap flow of intermediate trees decreased by 38.04%,48.79%and 25.54%,respectively,and the reduction of suppressed trees was 39.74%,58.09%and 59.86%,respectively.In addition,the overall pattern of the sap flow before and after rainfall was shown as leaf expansion period>leaf spreading period>leaf defoliation period,and the sap flow after rainfall during the leaf spreading period was significantly higher than that before rainfall(P<0.05).The sap flow of dominant trees,intermediate trees and suppressed trees showed no significant changes during the leaf expansion period(P>0.05),but the sap flow of dominant trees and intermediate trees showed a downward trend during the leaf defoliation period(P<0.05).The

关 键 词：寒温带 白桦 树干液流 降雨等级 

分 类 号：S715.2[农业科学—林学]