Two springs ago, my husband and I were concerned to find a fallen tree branch in the backyard after an overnight thunderstorm. While, thankfully, it didn’t damage our home or the surrounding power lines when it came down, it did unveil a major problem we would soon have to deal with. As it turns out, it wasn’t the weather that lopped off a sizable chunk of our towering ash tree. (Well, a wind gust might have been the final straw.) What caused the damage was something else entirely.