Nice photos. Thanks for posting them.
We have a similar "little critter". It lives underground and feeds on roots of high $$$ younger trees. Then, the trees just fall over.
I had some Gopher-mole "peanuts" shipped down. They are in a yellow plastic cone, and, cut the tip of the cone and shove it in the tunnel. I just look for escape holes in the ground, and drop a few peanuts in there. Seems to have lowered the rate of cut offs, or else, the trees are big enough now, that the roots are not as appealing ??
Here, people don't keep their fences in order, so, calves, horses and goats get on other farms and feed on leaves and bark. We are the only ones with any amount of replanting of timber, for several miles. Most farms are dairy for cheese processing by the owners and sell as block cheese.
At least, those tubes makes it easy to find the seedlings. I sprayed roundup in lines across the farm, to burn down the grasses, and, planted in the lines. 6-8 weeks later, it was difficult to find some of the seedlings.
I need to get my hard drive to where I can enable the mouse function, so I can access photoshop and photos of how we did the planting. For some reason, a Win XP repair disc will not enable the mouse function. XP boots up, but, I can't use the mouse or arrows to open programs.
Right now, I run Win 7 on a slave heard drive, which is a PIA.
I may go to Fl this coming spring, and will take that hard drive with me, to see if #1 Son can figure this out. Techs here are not very good.