When I took my first class in tree risk assessment, the instructor told us the story of a young couple that died after they sat on a hammock tied between two trees. Turns out the trees were standing dead and the couple were crushed as the trees came down upon them. The couple did not notice the trees were dead, but saw the hammock and proceeded to sit in it. The couple did not do a risk assessment on the trees before trusting that the trees would hold them up.
Which brings me to something I see quite often: swings, hammocks, zip lines, etc. in trees. Sometimes the object is drilled into the branch or trunk. Sometimes straps are wrapped around the branch holding the swing in place. Parents who love their children hang swings in trees for them. Trees are living things and change over time. Trees are not concrete pillars. Trees must put on a new ring of annual growth and straps that hold a swing can quickly become a tourniquet. A bolt through a branch starts the decay process and weakens the branch or kills the tree from oak wilt. Woodpeckers excavate a cavity looking for insects. The branch holding the swing is weakly attached and pulls away from the trunk. A storm comes through and starts a crack. There are endless scenarios.
Children start out small and lightweight, but over the years grow, putting extra weight on a branch. How is that branch doing all those years? Who is checking on the condition of the branch and can it hold the weight of your kid or the neighbor’s? A two-inch diameter branch falling from a sufficient distance can kill a person.
Any object drilled or strapped to the branch is not good for the health of the tree. Trees need to move with the wind, grow, drop branches naturally, and respond to their environment. If you want a safe place for you or your children to play, buy a swing set or a hammock stand instead. Don’t trust your loved ones to a tree that was never meant to be a playground.