The water that reaches the ground in forests by trickling down the tree trunks.
water that is caught on leaves, needles, branches, and bole and eventually flows down the bole onto the forest floor.
In Hydrology, stemflow is the flow of water down the trunk or stem of a plant. In tropical rainforests, where this kind of flow can be substantial, erosion gulleys can form at the base of the trunk. However in more temperate climates stemflow levels are low and have little erosional power.