利用森林水文学方法，对郑州市3种代表性行道树大叶女贞、二球悬铃木、雪松的冠外雨量、冠内雨量与树干径流进行了观测。结果表明：在一定降雨量范围内，这3种不同树种的冠外雨量、冠内雨率、树干径流量、树干径流率和树冠截留量都与空旷地降雨量正相关，而冠内雨量变异系数与树冠截留率则呈负相关。当降雨量较小时，这3种树种的冠内雨量、树干径流量、树干径流率和树冠截留量的差值较小；随着降雨量的增加，其差值逐渐增大。同一降雨量条件下，二球悬铃木树冠截留量最小而冠内雨量最大；大叶女贞树冠截留量与冠内雨量居中；雪松树冠截留量最大而冠内雨量最小；这3种不同树种的冠内雨量、树干径流量、树冠截留量与降雨量和降雨强度的关系可能与枝叶特征、树皮性质、枝条与树干夹角等因素有关。行道树对降水再分配的作用对“海绵城市”设计具有一定的生态学意义，但所有行道树的树干径流均很小，不利于补充树池范围内土壤水分。%Using the forest hydrological method,this paper observed the precipitation inside and outside tree crown and the stem flow of three representative street trees of privet ,sycamore and cedar in Zhengzhou City. The result showed that:in a certain range of precipitation,the penetration rainfall and its rate,the stem flow and its rate and the canopy interception of three tree species had a positive relationship with precipitation outside the tree canopy. But the variation coefficient of penetration and canopy interception rate had a negative relationship. When the precipitation was small, there was a little difference in penetration,stem flow and canopy interception among three tree species. When the precipitation increased,the difference increased gradually either. On the same rainfall condition,the sycamores tree had the smallest canopy interception but had the largest rainfall. The Cedar tree had the largest canopy interception and the smallest penetration. And the privet tree had the middle of canopy penetration and rainfall. The relationship among inside crown rainfall,stem flow,canopy interception,respectively,and rainfall and its intensity may be related to the characteristics of tree’s leaves,bark,branches,trunk angle and other factors. The precipitation redistribution funcion of street trees had an ecological indication for the“Sponge City”design,but the tree stem flow of all three street trees was very small,which was not favorable to replenish the soil moisture in the tree pool.
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