This birch tree in my backyard has "two" trunks "splitting" near the ground. One of them has a lot more die off than seems normal over the past several years. About 2/3 of the half in question budded and grew leaves this year, however they are drooping and some have already browned and dried. Not sure if its related but: A. There is a greenish moss sparsely covering a lot of the trunk. B. Also last time it rained a lot earlier this spring, a large number of mushrooms appeared near the base of the tree. C. There are holes in the tree trunk Please note that I am focusing the images on the concerning portions. There is about half of the tree that from the leaves and branches seems healthy, though both trunks are looking the same from the bottom. Please let me know if you want/need any close ups on any particular feature. I can also try again at a different time of day, the sun isn't positioned well for a good shot of the entire tree. What do you recommend? Thanks you!