I use raised beds with hardwood cloth underneath. It gets pretty expensive if you want more beds and have a bad vole problem. So every spring I have to rake up these large nut shells because they are everywhere. I can't identify the tree but the shells are as large as chestnuts but don't have the pricklies on the outside. They break in half or fourths and have a pointed end. So I came up with the idea to use them deep under the bed instead of rock or hardware cloth. But before I put them in I wondered if I was just making an apartment complex for the voles!! Any thoughts on this?? Thank you!!!