A: if the oak trees are I'll then it would affect their health which they'll star dying which means that all the biotic organisms that depended on those oak trees for shelter would also start dying which means all the organisms that depended on the oak tree organisms would also die and so on. That way this small change will affect the whole animal community in that area. B: this change in biodiversity will greatly affect the sustainability of the forest because the animals dying would disrupt the food chain in that ecosystem while killing the whole forest.
