We have a vole problem in our yard, still working out exactly how to get rid of them. In the mean time, we just planted a new apple tree, cherry tree, as well as haskap and saskatoon berry bushes. How can we protect all of our new trees from the voles? Also, is there anyway to tell they've been nibbling at the roots? Thanks!
The only thing I ever do about pest problems, is create suitable habitat for predators. In this case, it looks like you need snakes. Snakes need cover and somewhere to go at night where they won't be exposed. Rock piles and brush piles work really well. Mine live in machine built hugelkultur beds that have lots of spaces for snakes to breed and hide. Many snakes also like to have a water source. Given these two things, snakes and lizards will go a long way to controlling rodent problems. They will also gobble up slugs, snails, wire worms and many other bugs.
Not a quick fix, but one that is almost guaranteed to work in the long run.
I'm assuming you'll get a lot of snow in Alberta? That's always when the voles do the most damage, since they can tunnel through the snow cover and girdle the trees. I get a ton of snow, have a ton of voles (next to a huge meadow) and I'm just now experimenting with apple trees.
When I planted my apple trees, I made a small circular cage out of 1/4" hardware cloth about 2ft high. I made sure the bottom part of the hardware cloth was not smooth (little spikes sticking down). I wrapped the cage around the trunk of the tree and buried it as deep as I could without disturbing the roots. Ideally, this cage will go at least 12" above the snow line (I wasn't able to do this).
Other strategies I found in my research:
Get some of that 3" black drain tube, cut a slit in it along its length, and wrap it around the trunk. Backfill the inside with pea gravel
Keep grass near your orchard low cut (so they don't have the cover)
Plant some little windmills around the yard (see attachment). They'll create vibrations that moles/voles dislike
We'll see how all this does after this winter. I admit, I'm most nervous about vole damage. They go crazy over here in the winter, and I struggle to see a way past luck that I will realistically stop them. The good news is once a tree is established (5+ years), it's much less likely to suffer damage.