植物生态学报 ›› 2023, Vol. 47 ›› Issue (3): 0-0.DOI: 10.17521/cjpe.2022.0321

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Granier原始公式计算树干液流速率的适用性分析—以毛白杨为例

赵小宁1,田晓楠1,李新2,李广德3,郭有正1,贾黎明4,段劼4,席本野4   

  1. 1. 北京林业大学
    2. 北京时域通科技有限公司
    3. 国家开放大学农林医药学院
    4. 北京林业大学省部共建森林培育与保护教育部重点实验室
  • 收稿日期:2022-07-29 修回日期:2022-09-09 出版日期:2023-03-20 发布日期:2023-02-28
  • 通讯作者: 席本野

Analysis of the applicability of Granier’s original equation for calculating the stem sap flux density — take Populus tomentosa as an example

小宁 赵1,晓楠 田1,Li Xin2,Guang-De LI3,有正 郭1,Li-Ming JIAJIE DUAN5,Ben-Ye XI   

  • Received:2022-07-29 Revised:2022-09-09 Online:2023-03-20 Published:2023-02-28
  • Contact: Ben-Ye XI

摘要: 热扩散探针(TDP)在林木蒸腾研究中应用极广,其测定数据的计算精度直接影响对林木和林分耗水的精准定量。Granier原始公式(Fd=0.0119K1.231)是计算TDP测定数据的标准方法,但其准确性备受质疑。为系统了解Granier原始公式的适用性和明确对其校正的必要性,本研究以毛白杨(Populus tomentosa)为试验材料,采用室内茎段法和整树容器法,针对不同型号的TDP探针评估Granier原始公式的精度,并对比不同方法校正公式的应用效果。与茎段法实测值相比,Granier原始公式计算的液流速率平均低估52.3%–61.4%。通过茎段法和整树容器法得到的校正公式分别为Fd=0.0362K1.870和Fd=0.0105K0.976;且一种方法下得到的校正公式,在其它方法条件下应用时存在较大偏差。与Granier原始公式相比,整树容器法校正公式计算的大田生长状态下7 株林木的平均液流速率没有显著变化(P > 0.05),但茎段法和其它研究中得到的毛白杨校正公式的计算结果均显著变大(P < 0.05)。以整树容器法数据做对比,Granier原始公式的精度明显高于其它校正公式,其相对平均绝对误差和均方根误差分别为10%和0.0005 cm/s。此外,校正公式的系数在不同林木间存在较大差异,但其数值与探针插入非导水边材的比例呈显著负相关 (P < 0.001)。综上,利用TDP测定液流时,可能有必要对Granier原始公式进行校正,但不同方法校正公式的应用效果差异巨大,表明以往研究中得到的校正公式具有很大局限性。本研究未找到充足证据支撑“有必要采用校正公式以精确估算毛白杨液流速率”的观点,因此建议继续对该树种延用Granier原始公式。

关键词: 蒸腾, 水分利用, 水分关系, 热扩散, 杨树

Abstract: Aims To systematically understand the applicability of Granier's original equation to Populus tomentosa and clarify the necessity of its calibration. Methods Taking Populus tomentosa as the experimental material, this study used the stem weighing method and the whole-tree potometer method to evaluate the accuracy of Granier's original equation for different types of TDP, and compared the application effects of different methods. Important findings Compared with the measured values by the stem weighing method, the sap flux density calculated by Granier's original equation was underestimated by 52.3%–61.4% on average. The calibrated equa-tions obtained by the stem weighing method and the whole-tree potometer method are Fd = 0.0362K1.870 and Fd = 0.0105K0.976, respectively. The calibrated equation by one method has a large deviation when applied to other methods. Compared with Granier's original equation, the average sap flux density of seven trees in the field growth state calculated by the whole-tree potometer method calibrated equation did not change significantly (P> 0.05). But the calculation results of the stem weighing method and other studies were significantly larger (P<0.05). Compared with the data of the whole-tree potometer method, the accuracy of Granier's original equation is considerably higher than that of other calibrated equations, and the relative average absolute error and root mean square error is 10% and 0.0005 cm/s, respectively. In addition, the coefficients of the calibrated equation were obviously different among different trees, but their values were significantly negatively correlated with the ratio of probe insertion into sapwood without water conduction function (P<0.001). In summary, Correcting the original Granier's equation may be necessary when using TDP to measure the sap flux density. However, the application effects of different calibrated equations vary greatly, indicating that the calibrated equations obtained in previous studies have sig-nificant limitations. This study did not find sufficient evidence to support the view that it is necessary to use a calibrated equation to estimate the sap flux density of Populus tomentosa. Therefore, it suggested continuing to use the calibrated equation of Granier for this tree species.

Key words: transpiration, water use, water relation, heat dissipation, poplar