>>2424663leave no trace doesn't apply on your own private property, and its not really a big deal since you can eventually just tear it down. you can make an argument against chopping a few trees down or using some natural resources, but i'd argue its a necessary expense you'll have to make if you want to learn bushcraft/construction skills and survival skills. if you want to learn to swing an axe you'll have to cut down and limb a few trees there's no way around it. or in the case of treehouses and stuff, they're just cool when they're done right, and they're not harming a whole lot if they're out of the way AND not accessible to passer-by's or kids who might hurt themselves.
that's actually what i say is the most important and consider the most when i build shit out in the woods and leave it: if someone especially, you have to think throught the lens of what if a kid or a drunk/otherwise mentally not all there person came across it. if someone could realistically find it and fall into something or fall off of something you should do whatever you can to minimize that. bicycle lifts in treehouses is a classic for that, if you hide the controls well and build the treehouse high up + stealth.
my anecdote earlier totally goes against all this derp.
not everything you build in the woods has to be leave no trace. i've built a bunch of stuff through volunteer groups on public land like bridges or w/e.