Did you know that tree trunks are two degrees warmer than the ambient air? I first learnt of this from Dr Lincoln Brower who wrote a paper scientifically showing that to be true in the monarch overwintering colonies in the mountains of Mexico. Thousands of monarchs cling to each tree to insulate each other and derive warmth from the trees. 
Here in the Catskills, I can ascertain that the earth surrounding a tree melts snow faster as attested to by our dog, Amanda, taking a nap nestled to a maple tree.
