I live in Washington State and have a large cherry tree (trunk is about 18 inches dia) that has either a fungus or disease. The tree develops leaves, blossums, and cherries however the cherries seem to fall of before they are ripe or never fully develop. Every other year the amount of cherries are very diminshed. The treee looks like it has some kind of moss or fungus growing on it (see below), some of the growth is a soft green like moss, and the other is a flakey grey that crumbles when touched. I haven't determined if the green moss eventually dies and turns to grey. Can anyone tell me what this is and how to treat it?
The moss and lichen are generally regarded as harmless to the tree. The reduced fruit load could be due to poor pollination or other stress factors.
