高级检索
    马菁, 郭建斌, 刘泽彬, 王彦辉, 张紫优. 六盘山华北落叶松林分蒸腾日内变化及其对环境因子的响应[J]. 北京林业大学学报, 2020, 42(5): 1-11. DOI: 10.12171/j.1000-1522.20190468
    引用本文: 马菁, 郭建斌, 刘泽彬, 王彦辉, 张紫优. 六盘山华北落叶松林分蒸腾日内变化及其对环境因子的响应[J]. 北京林业大学学报, 2020, 42(5): 1-11. DOI: 10.12171/j.1000-1522.20190468
    Ma Jing, Guo Jianbin, Liu Zebin, Wang Yanhui, Zhang Ziyou. Diurnal variations of stand transpiration of Larix principis-rupprechtii forest and its response to environmental factors in Liupan Mountains of northwestern China[J]. Journal of Beijing Forestry University, 2020, 42(5): 1-11. DOI: 10.12171/j.1000-1522.20190468
    Citation: Ma Jing, Guo Jianbin, Liu Zebin, Wang Yanhui, Zhang Ziyou. Diurnal variations of stand transpiration of Larix principis-rupprechtii forest and its response to environmental factors in Liupan Mountains of northwestern China[J]. Journal of Beijing Forestry University, 2020, 42(5): 1-11. DOI: 10.12171/j.1000-1522.20190468

    六盘山华北落叶松林分蒸腾日内变化及其对环境因子的响应

    Diurnal variations of stand transpiration of Larix principis-rupprechtii forest and its response to environmental factors in Liupan Mountains of northwestern China

    • 摘要:
          目的   理解林木蒸腾日内变化及其对主要环境因子的响应规律,进一步阐释短时间尺度下环境条件调控森林蒸腾的机理。
          方法   以宁夏六盘山香水河小流域华北落叶松人工林为研究对象,在2018年生长季(5—10月)连续监测样树的树干液流变化,并同步观测气象条件和土壤湿度,分析小时尺度的林分蒸腾对环境因子的响应,并建立多因素影响的蒸腾模型。
          结果   (1)在小时尺度上,林分蒸腾量(T)对太阳辐射(Rs)和饱和水汽压差(VPD)的响应均呈二次多项式函数关系;随Rs和VPD的增加,T均先增加,当Rs和VPD分别达到666.7 W/m2和1.86 kPa后达到峰值,然后逐渐减小。(2)T对土壤可利用水分(REW)的响应符合趋于饱和的指数关系,T随REW的增加表现为先增加,当REW > 0.3后,T逐渐趋于稳定。(3)在确定T响应Rs、VPD和REW的类型并耦合形成蒸腾模型后,利用生长季内的奇数天小时观测值进行拟合参数,并用偶数天小时观测值进行验证,得到T响应多因素变化的耦合模型:T = (− 6.347 0 × 10− 5\begindocumentR_\rms^2\enddocument− 0.637 0Rs − 208.734 8) × (− 0.003 2VPD2 + 0.013 8VPD + 0.001 7) × (− 0.008 1 − 0.004 6(1 − exp(− 12.469 6REW))),该模型在校准阶段(R2 = 0.74,纳什效率系数(NSE)= 0.82)和验证阶段(R2 = 0.77,NSE = 0.84)均表现出较好的模拟效果。
          结论   在小时尺度上,林分蒸腾量可以由耦合了太阳辐射、饱和水汽压差和土壤可利用水分影响的耦合模型进行较好的预测。本研究结果可为精确预测变化环境下的华北落叶松林分日内蒸腾提供理论基础,同时模型的构建方法可为其他区域和其他树种的林分蒸腾模型的建立提供参考依据。

       

      Abstract:
          Objective   This paper aims to examine the diurnal variations of stand transpiration and its response to environmental factors in a Larix principis-rupprechtii plantation, and to further explain the regulation mechanism of environmental conditions to the stand transpiration in short time scale.
          Method   A field experiment was conducted in a Larix principis-rupprechtii plantation stand located in the Xiangshuihe Watershed within the Natural Reserve of Liupan Mountains, Ningxia of northwestern China. The sap flow of sample trees was continuously monitored in the growth season (from May to October) in 2018. The meteorological and soil moisture conditions were continuously measured simultaneously. The response of hourly stand transpiration (T) to environmental factors was analyzed, and a T model coupling the effects of multiple influencing factors was established.
          Result   It was shown that: (1) the response of T to solar radiation (Rs) and vapor pressure deficit (VPD) followed a binomial equation. The T firstly increased with rising Rs and VPD till to peak at the thresholds of 666.7 W/m2 and 1.86 kPa, and then gradually decreased afterwards. (2) The T response to relative extractable water (REW) of the 0−60 cm soil layer followed a saturated exponential growth function. The T increased firstly with rising REW, and then became stable when the REW was above 0.3. (3) The response functions of T each individual driving factors (Rs, VPD and REW) were determined using the upper boundary line method, and then were coupled to form the frame of T model. Thereafter, the observed data of odd-days and even-days were used for model fitting and validation. The fitted model is: T = (− 6.347 0 × 10− 5\begindocumentR_\rms^2\enddocument− 0.637 0Rs − 208.734 8) × (− 0.003 2VPD2 + 0.013 8VPD + 0.001 7) × (− 0.008 1 − 0.004 6(1 − exp(− 12.469 6REW))). The model was well calibrated (R2 = 0.74, Nash coefficient (NSE) = 0.82) and validated (R2 = 0.77, NSE = 0.84).
          Conclusion   The T variation can be well predict by the T model coupling the effects of solar radiation, vapor pressure deficit, and soil moisture conditions. This model can accurately predict the variation of T of Larix principis-rupprechtii plantation under changing environment. Meanwhile, the model establishment approach used here can be a reference for developing the stand transpiration model in other regions and for other tree species.

       

    /

    返回文章
    返回