Answer:
The Ash Trees with Ash Borer are being cut down as a way to maintain the stability of the other Ash Trees.
Step-by-step explanation:
As stated in the information given, "Ash trees are being removed when they show signs of the Ash Borer, a parasite that affects only Ash Trees and kills them off."
To preserve the other trees, these trees with the parasite must be cut down as a way to stop other trees from gaining this parasite. Its a preservation method for Ash Trees.
Hope this helps!