Mysterious Tree Damage

Last Wednesday I posted evidence of tree damage in my woods. 

click on image for a closer look

 

Bark stripped and shredded from the limbs of live ash trees.  Having never seen anything like this before I was puzzled as to who or what did this. 

I sent my photos over to my pal Jamie who is a biologist and Senior Wildlife Outreach Specialist with UW Extension and she immediately emailed me an answer. 

Bark stripping by tree squirrels - grey or fox and hopefully my trail camera will confirm this by catching them in the act.

I knew we had both species of squirrel in the woods yet I've never encountered evidence of this behavior.  Sure, beavers, porcupine, mice and rabbits will gnaw and strip bark from a tree.  I guess I can add squirrels to the list too.  As it turns-out, squirrels prefer to strip branches that are horizontal, but have been known to strip trunks too. The damage can be extensive.  Bark stripping generally occurs in late winter - yet it can occur in the spring if trees don't produce mast.

There are all sorts of theories for this behavior - including discomfort caused by pregnancy, snacking and just plain enjoyment.  Even the scientists are not completely sure of the root cause.  Go figure.  You can learn more about bark stripping here.