Unsure which trees to cut for firewood? For a fee, the Catskill Forest Association will mark your best trees for future timber or wildlife value. You can then cut the trees around them for firewood, giving your best trees more room to grow.
Treating your ash trees may be a good option if you have a few select trees that you want to save. Treatments can be expensive, so this is more suitable for trees near your home or cabin than in the woods. Contact an arborist to discuss treatment options.