Thanks so much for all your help! And sorry it has taken me so long to respond!! I really do appreciate your responses and the wealth of information you provided. I looked up the Michigan State bulletin on Pine Wilt, as suggested. It was very helpful. It also confirmed the diagnosis made here. I agree that it is Pine Wilt that is killing our trees. I'm attaching a picture of a stump from a tree that died a couple of years ago. As predicted above, there are many, many small holes in the lower trunk. I don't remember seeing the blue-stain fungus, but then, it was several years ago and I wasn't looking for it. The MSU bulletin said that there is a high correlation between high temperatures and the incidence of Pine Wilt, especially when the trees are already stressed by drought. Sounds like conditions were just right for the last two years. I'm also attaching pictures of the trees from 7 years ago, when we moved here. I agree that they don't look full and robust, but I can't see that they've changed that much. We have a well and they are at the back of the lot, so watering them is not practical. What would be the best way to feed them? I'm also attaching a picture of the ground around the trees, as you requested. We don't do anything but mow there. Does anyone have a suggestion for replacement trees? I know we should use natives. What would be best? It's the west side of the property adjacent to a farmer's field, so it's quite windy. Would White Pine be a good windbreak? Thanks to all of you for your help and suggestions! I certainly do appreciate it!!