Thanks for your question that has now been referred to me.  I am having a bit of difficulty in understanding the two pictures you previously sent.  I see a vertical piece of wood with the top end gnawed off.  Is this the end that was previously underground?  What does the other end of this piece of wood look like? If this piece of wood is completely loose, could you please send me a horizontal view of it?  

Many thanks and I look forward to your response.  Thats for using our forum.

Sorry for the delay, I didn't see this second response. You are looking at the root system, or where the root system should be on my tree. I am literally holding my 3 year old pear tree upside down. The other end is just a dead pear tree. That is why this whole question (and picture) seem confusing. I pulled my tree out of the ground after 2 years of good growth and this year (year 3), it just never grew vegetation after winter. A stiff tug and it came out of the ground as you are looking at it. Zero root system, not a single piece of root even though it was buried underground. To boot, it look's like beaver sized chew marks, but there are no large animals that live near my orchard (mostly open prairie). There was a tree guard on the tree itself too.  I have trapped some pocket gophers within 100 yards of there, but nothing near the orchard. My dog is free range, so no den animas are in the area. I have racked my brain and other than a rare undiscovered species of underground beaver,  this whole things doesn't make sense to me.

Good morning,

I have no good answer for you. Sorry to disappoint you. There are no underground beavers. This is an old injury. It did not happen overnight. I’m curious as to why you are just now discovering this. I would have expected that your pear tree would have shown distress long before this. I do take note of the fact that you have been seeing unusual things for over three years.

Throw it away. Plant a new tree. Nature hold its mysteries.

Thanks for challenging me. Thanks for consulting our forum.