You failed to mention the mesh sizing, but for fruit trees even rat wire with .25" meshing probably wouldn't much damage the root structure. If you're using 1" Chicken wire the damage would definately not be significant in my opinion.

I am speaking from the experience of growing hundreds of fruit trees in mesh bags in my nursery. I use in-ground grow bags that are nitted with a substance too tough for the roots to move aside or stretch. The bags do weaken the roots as the pores are very small. This allows me to easily pop the bags out of the ground, snapping most of the roots at the outside border of the bags.

If I leave the bags in the ground too long, however the weakened roots still gain enough strength to make tree removal difficult and they eventually seem to anchor as well as trees with unobstructed roots.

I have done the same thing for all my trees. I just use the wire that is used by plaster and stucco people that looks a lot like chicken wire. It's just as effective and lots cheaper. This wire will rust out and be gone in 5 years so as the roots get bigger the wire is to old and rusted out to harm them. Buy then the tree is big enough that some gofer activity will not cause that much damage (unlike a new tree where one gofer could eat all the roots in about one meal) Normal gofer control is good enough for mature trees.
also, FYI I use a trap that has a tube and a cap, with the trap in the capped end of it, and a small hole about the size of a soda straw to let in light. The gofers come into the tube to respond to the light (they want to close off their tunnel again). I get very good results with these traps.
A few years ago the farmer next to us had been leaving that field fallow. When he came in and started working that land again every gofer in 60 acres needed a new home, and guess where the landed? yep, in my yard. (sigh) 93 gofers later we had the problem pretty much under control.

Are moles the same as gofers in terms of the root damage they can cause? My understanding is that moles don't eat the roots of plants ...

~ blink blink ~

Are moles and gofers the same thing?

I'm going to look it up ... :)

The only real protection from gophers is to trap them as they make their presents known. Everything else is only a temporary distraction in a permanent planting such as an orchard. Al

I understand that the wire openings must be 1/2" or smaller to keep gophers out, which was why I was concerned about girdling roots as they grow larger.

And yes, gophers are completely different animals than moles, though both make tunnels and mounds. Moles eat grubs and bugs, so actually have some benefit for a garden, despite tearing it up. Gophers on the other hand eat vegetative material, chiefly the roots of plants, and kill all sorts of grasses, vegetables, flowers, shrubs and even young trees.

We do trap, perhaps not very effectively. It is legal here, though I understand not everywhere. We have a hillside garden right on the edge of an undeveloped area, and will have an unending supply of new gophers for many years to come. I'm going to lay in a stock of new gopher cages to protect my new fruit trees and the grapes I plan to put in late this winter.

Rosefolly

Gophers are moles are different. Gophers love roots and eat LOTS of them. They eat the roots of stone fruit and mango like it was cheese cake. I'm not sure what moles eat.
I agree on using the wire for new trees while they get established. At least I should say that is what I do and it works for us. New trees just can't withstand a gopher attack since they have so little roots to start with. I sure feel your pain about the "unending supply of new gophers for many years to come". Any chance you can get a cat thats a good gopher hunter? May not get them all but every little bit helps. Have you seen the traps in tubes that I was talking about? They really work quite a bit better than the standard snap traps and the cat can't get to the "business" end which is pointed into the tunnel, so they are safe around the cat too.
I'm guessing there is some beauty and peacefulness to having the open space next door. Just try not to fall in a gopher hole as you watch the sunset! ::smiles his jolly smile::

Yes, i did a bit of reading, and not surprisingly, you're all spot on. The moles in my area are far less of a concern.

Here's what i read about gophers and wire:

"Because of the expense and limited practicality, exclusion is of little use. Fencing of highly valued ornamental shrubs or landscape trees may be justified. The fence should be buried at least 18 inches. The mesh should be small enough to exclude gophers; 1-inch hardware cloth will do. Cylindrical plastic netting placed over the entire seedling, including the bare root, reduces damage of newly planted forest seedlings significantly."

Good luck! And remember, Gopher Broke! :)

Softmentor, is this the kind of trap you mean?

http://www.amazon.com/Black-Hole-Rodent-Trap/dp/B0007O24US/ref=pd_bxgy_ol_text_b

Estreya, thanks for the good wishes.

Harvetman, thanks, I am encouraged and will get some netting before I plant the new trees this winter.

Rosefolly

well, that one is a little different. The ones I have are in a similar tube but then have a conventional trap, the kind that has 2 wires that close together. The one in the picture has a wire loop that draws up. May work though, haven't tried one like that.
Actually, I only have one store bought one. The others are hand made using old aluminum irrigation pipe, PVC end caps, and conventional traps. (shhhhh I kinda stole the idea from the one I bought)
I still think using wire is good when planting new trees to give them time to get enough roots to be established. That first year is so important. I would never use plastic netting in the ground. The rasceles would probably think it was a "chew toy" and chew through it just for fun anyway. I use metal, knowing that it will rust out in 3 to 5 years, but that is what I want so the roots will not be strangled by wire as they get bigger. I use the cheap construction wire they use to stucco houses. I stretch the wire out across the bottom and out to the sides of the entire planting hole. Then plant as usual. Keeps the out for a couple of years. That's all I need to let the tree get a good start.