Fuzzy41, you can eliminate the tree as the culprit. There isn't a tree with foliage long enough to attenuate 72MHz signals.

Now, if we were flying with 900MHz radios, pine needles, especially wet pine needles, can completely block signals.

Like the others said...it's those three seconds of high anxiety while the plane disappears that does most of them in.

Sorry for your loss & hope you find it!