Q:I recently had a treehouse removed that had been bolted into two oaks in my yard. The holes remaining where the bolts came out are about 3-4 inches deep. Is there anything I should/could do to fill the holes or help the tree recover?

A: : Frankly, I'm amazed you were able to remove the bolts!

If a bolt or screw has been in a tree for a long enough time, the tree will usually grow around it and incorporate it into itself, making it almost impossible to remove.

We see this happen time and time again with cables we've installed in trees to help support weak connections. I've even seen trees that have grown out over the hardware and started to engulf the cable itself.

In any event, and believe it or not, I suggest re-installing the bolts you took out. This may help preclude decay organisms from entering the now-fresh wounds, and it will provide a stable surface for the tree to produce callus tissue on to close over the wound. Be sure the bolts are set in snugly.

Eventually, the tree will grow around the hardware, and after several years you may not even see where it is. In my opinion this will be as effective, or more so, than plugging the holes with anything else at this point.

However, you should still try to remember where the hardware is. If the tree ever needs some surgery, and hidden bolt can wreak havoc on a saw!