It looks like rabbits have made a feast of my Japanese Maples last winter and stripped 75% of the bark off my Red Dragon which subsequently died. The Waterfall Maple had put out leaves this spring but I am concerned that the damage has actually girdled the tree. See photos.
Will the tree heal on its on?
Or will I need to do a bridge graft?
If the latter, where do I graft the bottom to? I can’t seem to find any bark on near the base to make the bottom grafts.
Thank you for contacting Toronto Master Gardeners.
It is sad to lose young trees like this. I am not sure if this picture is from the tree that died or the one that has some leaves.
The layer under the bark of a tree is called the cambium. It contains the xylem and phloem cells that transport all the water and nutrients up the tree and the carbohydrates ( food) from the leaves out to rest of the tree. When the entire trunk is girdled (encircled) the tree is unable to get water and nutrients and the tree will die.
When a tree has damage but still has some cambium left to move water and nutrients and food around it will continue to struggle along at least in the short term. The tree builds a barrier around damaged areas which isolates the damage from the tree. This way it protects itself from infections and routes the flow of its nutrients etc. around the damaged area. So yes the tree does fix itself but if the damage is too large the tree can not grow and thrive and will eventually die.
If 75% of your tree is girdled I fear that is too much for a young tree to compensate for. You can leave it out of curiosity to see how it progresses but you probably want to start looking for a replacement tree.
The grafting you mentioned is a complicated procedure that needs to be performed in the spring long before leaves come out. Grafting is better for older trees and often is not successful. It opens the tree up to many infections as well. I have included a link below that goes through the steps required. There is also a photo that shows what it looks like when it succeeds. If your tree is for ornamental purposes a graft would certainly take away from the tree’s appearance.
When preparing for the winter next year you may want to protect the trunks of your young trees to avoid this happening again. When protecting your trunk in the winter you need to go higher than the the snow line. Rabbits are just as happy to sit on the snow and eat higher up as eat at the base of the trunk. There are commercial protections you can buy to wrap around your trunk or you can fashion a cage with chicken wire to keep the rabbits away from the trunk. If you wrap your trunk be aware in the spring that it will trap moisture against the trunk which can cause other problems.
I am including a link below which talks about creating a rabbit fence.
Good Luck.
https://msue.anr.msu.edu/news/bridge_grafting_as_a_life_saving_procedure_for_trees
https://www.ipm.iastate.edu/ipm/hortnews/2011/10-12/rabbits.html