There is an easy way to remove fenceposts, if you have a pickup truck that can closely approach. Attach a chain at the base of the post, and put a wheel next to the post (a rim) that the chain drapes over before being attached to the truck, which will pull the chain.
The rim transfers the force of the pull from the truck from horizontal to vertical, pulling the fencepost straight up, which extracts it much more easily.
Hope that helps you create this amazing forest.
Thanks!