Options for supporting treehouses in living trees
There are generally 3 ways to support a treehouse in a tree, each with it's own pros & cons:
- Supporting the treehouse from the ground with minimal or no tree interference. - This is the best way to ensure that the treehouse causes the least possible damage to the tree. Go ahead and build around the tree, but keep all parts of the treehouse several inches or a foot away from the trunk, depending on the growth rate and maturity of the species. Digging holes around the trunk will likely do some root damage, but this usually pales in comparison to the damage done by other attachment methods. This may not seem like the most nostagic tree house support method, but if you want to minimize the tree damage, this is indisputably the way to go. Over time, smaller trees may grow thicker, over, and around your treehouse, making the structure feel more authentic.
- Suspending the treehouse from the tree without penetrating the bark. - If you suspend the treehouse with slings, cables, chain, or ropes, you might be able to support the weight without penetrating the bark of the tree. This causes very low initial impact and debatable impact in the long run. Take care that the tree does not grow around the slings or anything else that bears the load. Do not allow the chains or ropes to girdle the tree. Also, beware that the load is not excessive which could restrict the vascular movement of nutrients & starches in the compressed area of tree tissue (it's like you trying to pump blood past a torniquet - make sure it's not too tight).
- Installing attachment bolts into the tree tissue to pin or perch the floor beam/joist system. - The most traditional method of treehouse building is to bolt the beams & joists into the tree. Depending on the attachment method, this can cause varying levels of tree injury and growth interference over time. Basic treehouse attachment methods, such as those that pin beams to the tree with common lag bolts, tend to cause less intial trouble for the tree, but more long term trouble. More advanced methods, such as the advanced methods discussed at tree house bolts cause more initial damage because the hardware is bigger, but will allow your trees a growing chance to carry the treehouse for decades with minimal interference or future harm.
No matter which treehouse support methods you lean towards, it is important to understand the pros & cons and honestly evaluate what stresses your trees can reasonably handle.