Fyldewhite
Tour Winner
From your description it sounds like a penalty. Unless for some reason that was the only way he could get into the tree??
He could have easily taken a stance without touching the tree, however, he would have had a dodgy stance and prob not been able to hit a full shot at the green.
Sorry, missed this bit in earlier post as well as Chrisd's addition to the decisions. Certainly a penalty.
In situations like these it's usually pretty obvious what's fair and not fair at the time but there's inevitably a grey area. The key bit is taking a stance that improves things by the least possible amount to enable you to play it regardless of which direction you want to hit it.