I have two apple trees, both semi-dwarf grafted trees. They're between 25-30 years old. We've kept them pruned as best we could, they are about 15 ft. tall. They have struggled to produce good fruit due to worms, cedar apple rust (early on, which we solved by removing cedars), and increasing shade, but they were good trees until last season. They lost some wood way up in the tops. This spring, we pruned that out, but there is a lot more dead wood now, most of one tree and a good portion of the other. They just seem like they are dying. We have not had particularly bad winters, drought or anything like that the past few years.

I know grafted trees don't last forever, but is this how they go? They just up and die after 25 years?