Q: I have a 30 - 40 foot Oak tree on my patio in the South of France and during some excavation work some of the bark was damaged and it is now dripping sap from the 'wound', what is the best thing to seal it with?
I am concerned that because the sap is leaking it might be starving some of the tree and it is also making a bit of a mess on the patio. I do not want to lose the tree.
The callus tissue that will form around the edge of the wound will tell you where the tree is "repairing" itself. If there are any very loose shreds of bark sticking out you can carefully cut them off, but I would wait until the callus tissue forms to tell you exactly where to do this.
Do not cut into the callus as this is living tissue, and you will only further the wounding process.
Be sure to water during any extended dry spells. Since the tree has lost living bark and cambium it has less tissue that transports water up the tree, and not having enough water only adds to its stress.
I also recommend that you have a qualified arborist examine the tree to see if any other measures need to be taken.