My apologies for the delayed response, I didn't get a notification indicating you had responded.  The trails are maintained/managed by Huntsville Area Mountain Bikers (HAMR) in coordination with Monte Sano State Park and the North Alabama Land Trust.  I am part of the trail committee for HAMR and work extensively with both the state park and land trust.  The trails I deleted were decommissioned several years ago by all parties involved. Some trails were too difficult to maintain while others were removed at the request of the property owners.  The trails that traversed private property were originally approved by the owners but some owners ended up putting their property up for sale and asked that we remove them, so we did.  

The point is, I'm part of the organization that manages the trails on Monte Sano and we decommissioned/removed them several years ago for the reasons mentioned above - they’re not authorized by land managers or property owners.