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    辽东半岛赤松和蒙古栎林降雨再分配特征及其相关性分析

    Precipitation redistribution characteristics and its correlation analysis of Pinus densiflora and Quercus mongolica forests in the Liaodong Peninsula of northeastern China

    • 摘要:
        目的  降雨再分配是森林生态系统重要的水文过程,分析辽东半岛地区赤松和蒙古栎林降雨再分配特征,为区域典型林分的生态水文分析及模型建立提供参考。
        方法  以辽宁仙人洞国家级自然保护区内的赤松和蒙古栎林为调查观测对象,选择林外降雨量(POF)、林内穿透雨量(TF)、树干径流量(SF)和树冠截留量(IF)为指标,应用回归分析法建立林外降雨量与各类指标的关系方程,并分析2种林分的降雨特征及其变化规律。
        结果  (1)赤松林穿透雨量、树冠截留量和树干径流量分别为388.5、215.3、66.5 mm,占林外降雨量的57.96%、32.12%、9.92%;蒙古栎林穿透雨量、树冠截留量和树干径流量分别为421.7、119.0、55.5 mm,占林外降雨量的70.73%、19.96%、9.31%。(2)低强度降雨时,赤松和蒙古栎林的初始迟滞时长1 h左右,而中等和高强度降雨时,迟滞时长较短,明显小于1 h。且赤松林的树冠截留迟滞时间较长,迟滞作用更强,截留效果更好。(3)林外降雨量与穿透雨量、树干径流量呈极显著线性正相关(P < 0.001),赤松林和蒙古栎林产生穿透雨l、树干茎流量的最小降雨量分别为4.2、5.8和2.0、2.5 mm。(4)赤松和蒙古栎林的树冠截留量与林外降雨量呈极显著(P < 0.001)二次函数关系,树冠截留作用与林外降雨同时产生。当林外降雨量分别大于90.0、70.0 mm时,赤松和蒙古栎林的树冠截留量分别在10.0、7.0 mm左右。(5)林外降雨量与树冠截留率呈极显著负相关(P < 0.001)的幂函数关系,当林外降雨量分别大于90.0、70.0 mm时,赤松和蒙古栎林的树冠截留率趋于平稳,降低到20%和10%左右。
        结论  降雨再分配过程中,赤松林的树干径流量、截留量和截留率大于蒙古栎林,而赤松林穿透雨量小于蒙古栎林,赤松林降雨再分配作用强于蒙古栎林。林内穿透雨存在迟滞效应,迟滞时长受降雨强度和林分类型影响,且赤松林的迟滞时长大于蒙古栎林。林外降雨量与树干径流量、穿透雨量、树冠截留量呈极显著正相关,与树干径流量、穿透雨量呈线性函数关系,与树冠截留量呈二次函数关系,与树冠截留率呈极显著负相关的幂函数关系。

       

      Abstract:
        Objective  Precipitation redistribution is an important hydrological process in forest ecosystems. Analyzing the precipitation redistribution characteristics of Pinus densiflora and Quercus mongolica can provide a reference for the analysis of ecological hydrological parameters and model establishment of typical forest stands in eastern Liaoning Province of northeastern China.
        Method  Taking the Pinus densiflora and Quercus mongolica forests in the Xianrendong Nature Reserve as the survey and observation objects, the selection of precipitation outside the forest (POF), throughfall (TF), stem flow (SF) and canopy interception (IF) were used as indicators. The regression analysis method was used to establish the equations of POF and various indicators, and the precipitation characteristics and their changes of the two forests were analyzed.
        Result  (1) In the Pinus densiflora forest, TF, IF and SF were 388.5, 215.3 and 66.5 mm, accounting for 57.96%, 32.12% and 9.92% of the POF, respectively. In the Quercus mongolica forest, TF, IF, and SF were 421.7, 119.0 and 55.5 mm, accounting for 70.73%, 19.96% and 9.31% of the POF, respectively. (2) At low intensity precipitation, the initial lag time of Pinus densiflora and Quercus mongolica forest was about 1 h, while for medium and high intensity rainfall, the lag time was shorter, significantly less than 1 h; and the canopy interception time of the Pinus densiflora forest was longer, the hysteresis was stronger, and the interception effect was better. (3) The rainfall outside the forest was significantly and linearly positively correlated with the penetration rainfall and stem flow (P < 0.001). The minimum rainfall producing TF and SF by Pinus densiflora forest and Quercus mongolica forest was 4.2 , 5.8 mm and 2.0, 2.5 mm. respectively. (4) The canopy interception of Pinus densiflora and Quercus mongolica showed a significant quadratic function relationship with rainfall (P < 0.001). Canopy interception occurs simultaneously with rain outside the forest. When the rainfall was greater than 90.0 and 70 mm, the canopy interception of Pinus densiflora and Quercus mongolica tended to be stable at about 10 and 7 mm, respectively. (5) The rainfall outside the forest had a very significant negative correlation with canopy interception rate (P < 0.001), showing a power function relationship. When the rainfall outside the forest was greater than 90.0 and 70 mm, the canopy interception rates of Pinus densiflora and Quercus mongolica forest tended to be stable, decreasing to about 20% and 10%, respectively.
        Conclusion  In the process of precipitation redistribution, the SF and IF of the Pinus densiflora forest is greater than Quercus mongolica forest, while the TF of Pinus densiflora forest is smaller than Quercus mongolica forest. Redistribution of Pinus densiflora forest is stronger. There is a significant delay in TF in the forest, the lag time is affected by rainfall intensity and stand type, and the lag time of Pinus densiflora forest is greater than Quercus mongolica forest. The POF is significantly positively correlated with SF, TF and IF, and it has a linear function relationship with tree SF and TF. It has a quadratic function relationship with the IF. There is a significant negative correlation between the POF and canopy interception rate, and it is a power function relationship.

       

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