I've got a tall tree in the backyard that we use to practice belaying / abseiling (rappelling). However, the lowest part of the trunk does not have any branches until up to 20' / 6m, so we use a lean-on ladder. Which is a shame because I'd rather climb those feet and not "waste" them!
What would be the best way to attach wall climbing hand holds or any other things that could give us a challenge but without harming the tree (I don't want to put thick and long anchors inside a living trunk)?
So here's what I'll do. As advised by @Jory Geerts, I'll build a round-the-trunk planked miniwall. Meanwhile I've anchor-hitched 30 feet of 10mm static rope to the lowest branch and we Texas prusik it! Great practice and workout (the transfer from the rope to the tree branches is the hardest part)!