If and when you get a tree jump up and grab your plane out of the air and trap it in it's branches. Don't climb the tree! It looks small from the ground, but when you are up swaying in the branches. You realise how high it really is.
The best fix we have found in our club.( Noarlunga Aero-sport Club) is to use a sling shot attatched to a good strong fishing line. (50 lbs, 25 kilo) should do it. You can pull the small branches, around you plane, off the tree, giving you enough space to then pull your plane out of the tree. Don't try to catch the plane as it falls! One fellow cut his tendons in his hand doing this and the plane still broke. A blanket or tarpaulin with a few helpers is a good idea to catch it.
Hope this helps retrieve a few more planes!