Why does my tree foam when it rains?
Our Arborists answer:
This occurs when rain water dissolves chemicals from the treebark as it flows down the stem of the tree. This changes the surface tension of the water, so that when it drips down towards the base of the tree, air is introduced due to the turbulence of the water, and foam is formed because of the altered surface tension.
This also occurs in other areas such as rock (rock foam) and in rivers and oceans, where phosphates combine with water and air to produce foam.
Tree foam happens in all types of trees and is noted as occurring in all continents where trees grow.
In conclusion,there is no need to call your local tree service. If there is foam on your tree during or after rain it is nothing to worry about. In fact it looks quite magical, even snow like, so its something to enjoy.