My own personal opinion is that cutting down old trees should never be taken lightly. I have gone to many campuses that are devoid of trees and are all concrete jungles of new construction. Having those oak trees on UL's campus really gives it a great southern feel.
With that being said, one of the general aspects of environmentalism is the proposition that we did not inherit the earth from our parents but are leasing it from our kids. Planting five new trees to take each one's place leaves the campus in a better posture, tree-wise then it previously is.
While I think the two most important features of UL's campus are red brick and oak trees, I think the University did its due diligence and took an environmentally sustainable course of action.