Experimental study on the mechanism of canopy interception using artificial Christmas trees

树冠截留量(降雨时的蒸发量)是在室外地点用放在托盘上的人造圣诞树(高65厘米到240厘米)测量的。林冠截留量占降雨量的比例在10%-20%左右，与实际林分相当。间伐减少了冠层截留；然而，我们发现了间伐增加冠层截留的情况。通过对降雨过程中的蒸发量、暴雨间歇期的蒸发量和降雨停止后的蒸发量三个林冠截留要素的测定，发现降雨过程中的蒸发量占林冠截留量的大部分。这一结果支持了一种假设，即雨滴撞击树冠产生的飞溅水滴会蒸发。

Canopy interception (evaporation at the time of rainfall) was measured at an outdoor site using artificial Christmas trees (65 cm to 240 cm in heights) placed on trays. The ratio of canopy interception to rainfall was within the range of a little more than 10% to some 20% that was comparable to that in actual forest stands. Thinning reduces canopy interception; however, we found a case that thinning increases canopy interception. Three canopy interception elements, evaporation during rainfall, evaporation during storm break time, and evaporation after the cessation of rainfall, were measured, and it turned out that evaporation during rainfall accounted for most part of canopy interception. The results support a hypothesis that splash droplets produced by raindrops hitting canopy evaporate.