Usually, a more open view is desired here in the mountains. Some people like a lot of trees, some people don't. that all depends on the buyer. You may have some buyers turned off by the fact that the lot has burned, but then again, this will draw in other buyers. Also, in this case, if the foundation isn't usable, to "stage" the property, remove as much of the debris that you can to make it more accessible and buildable, so buyers can see the potential in the land and the view. It would be nice to plant some trees, but then again, if you're not going to live/build there, leave that open to the new owners to do. Maybe offer some credit for purchasing new trees as a gesture.