How much of a problem are the bears in your area? I live now in an area that has occasional bears, and for the most part, they have enough to eat in the local forests that they aren't much of a problem. I used to live on the outskirts of Sequoia National Park. Again, we had the occasional bear wander through on its way to the river, but most of the bears stayed up in the park area. However, one year there were few berries in the park area, and our town was inundated with bears. I think they decimated many, many gardens that year.
If you really want to grow something there, you can install an electric fence around the trees. There are electric fences powered by solar. We use one along one side of our backyard fence.