小兴安岭原始红松林降雨截留观测及分段模拟

以小兴安岭原始红松林为研究对象,通过119场降雨的观测,对原始红松林的降雨截留再分配进行系统研究。结果表明:1)研究期内小兴安岭原始红松林的穿透降雨量、树干径流量和冠层截留量依次为636.04、14.62、177.84 mm,分别占林外降雨量的76.77%、1.76%、21.47%;2)原始红松林的穿透雨率、林冠截留率与降雨量之间均呈对数关系(P0.01),而穿透雨量、林冠截留量与降雨量之间均呈线性相关关系(P0.01);3)当降雨量0.5 mm时,原始红松林开始产生树干径流,且树干径流量和树干径流率均与降雨量呈正相关关系(P0.01);4)在原始红松林水文过程中,通过变异系数比较可知,树干径流的变异性最大,穿透雨变异性最小;5)分段模拟和分类回归树的结果显示,林冠截留与降雨量拟合曲线的分割点为2.3和9.8 mm,且与整体回归模型相比较,分雨量段的林冠截留预测模型精度高,更符合林冠截留的生态水文过程。 

Canopy interception in original Korean pine forest: measurement and dividual simulation in Xiaoxing'an Mountains,northeastern China.

The interception of precipitation by vegetation and subsequent evaporation during and after rain events are an important component of the hydrological budget of forest ecosystems, particularly for forests in ecologically and hydrologically sensitive regions such as the original Korean pine ( Pinus koraiensis ) forest. The evergreen Korean pine is the dominant canopy species in Xiaoxing'an Mountains, northeastern China. We investigated the rainfall redistribution effect and its variation in the original Korean pine forest in Liangshui Nature Reserve via 119 rainfall events. 1 ) The throughfall, stemflow and canopy interception in the original Korean pine forest were 636. 04, 14. 62 and 177. 84 mm, respectively, which accounted for 76. 77%, 1. 76% and 21. 47% of rainfall in the open field. 2) In the original Korean pine forest, the logarithmic relationships were found between throughfall rate, canopy interception rate and precipitation in the open field ( P<0. 01 ) , while it was a linear function between throughfall, canopy interception and precipitation ( P<0. 01 ) . 3 ) Stemflow was generated when the precipitation in the open field exceeded 0. 5 mm, and with the increase of rainfall, the stemflow rate increased ( P<0. 01 ) . 4 ) The maximum coefficient of variation was observed in stemflow and the minimum one in throughfall in the hydrological processes. 5 ) Dividual simulation and regression of classification showed that the break points of the interception-rainfall fitting curve were at 2. 3 and 9. 8 mm. Compared with the overall regression model, the dividual simulation had higher precision and conformed better to the eco-hydrological processes of canopy interception.