sorry to be so slow in replying, but found this at the link below.

Vines that climb up trees slowly kill the tree from the base upwards by enveloping branches and twigs, blocking sunlight, causing branch and eventual tree death. The added weight of vines also makes trees susceptible to blowing over during storms. English ivy has been confirmed as a reservoir for bacterial leaf scorch (Xylella fastidiosa), a harmful plant pathogen that affects a wide variety of native and ornamental trees such as elms, oaks and maples.

I have seen ivy on trees and thought it looked nice, but I guess if left to grow for too long of a period, that it would be very detrimental to a tree.

I've seen first hand that wild grape vines, Japanese honeysuckle, and even the native trumpet vine (Campsis radicans) have managed to kill large trees.

Sue

Here is a link that might be useful: English Ivy