According to scientists at Penn State University, spotted lanternflies do not typically kill the trees and plants they feed on, but they can cause branches and segments to die off. However, they have been found to kill cultivated grapes, which can have devastating consequences for vineyard owners and regions that heavily rely on vineyards to create jobs and generate revenue. They have also killed the Ailanthu altissima, known as the tree of heaven, though this is classified as a noxious and invasive weed tree.

Aside from removing dead or diseased branches, you should prune your trees somewhere between every one and three years. Some people—particularly commercial farmers—prune their apple trees yearly to produce higher yields. This is the best way to promote tree health. That said, the average homeowner can get away with hard-pruning their mature apple tree every other year or every three years. 

Unfortunately, if you cut the top off a palm tree, it will die. Instead of budding or branching out, the top begins to slowly rot. That's why having a professional tree trimming at least twice a year is a good idea. If you don’t have experience with trimming your palm tree, you might accidentally cut the top off, leaving a dead and rotting tree in your wake.

If the roots are still alive, the dead tree will usually try to put out new shoots. That doesn’t mean the tree will survive or that the dead parts of a tree will come back to life. If parts of the tree have died and turned gray or rotten, nothing will bring them back to life and they need to be safely removed.