My dad lives on the road north and west of the golf course (top of the map).  A lot of the land is private.  It is also lowland swamp and not good mountain biking.  The light green double line between roads in the left lower quadrant are power lines.  Very hilly but probably rideable.  If you get lost or break down in Hartley and walk out to the west you end up on Howard Gnesen.  Much shorter than walking back to the nature center.  Mostly downhill back to UMD.  You can also drop into trails from there to Hartley park with a short hike from the road if you are coming up from west Kenwood.

I selected the map for area 10. SLC-Parcels-10.kmz. It seems to show every parcel of land, and who is the registered taxpayer on the parcel, in St. Louis County.

Much of the area in question is tax-forfeited land. You do have to have the Google Earth software on your computer for it to work.

My first reaction to that revelation is that it's attractive to think about the prospect of expanding the parks.  My second thought was to recall that I'd heard that substantial portions of some of the existing parks are tax-forfeited county land, rather than city-owned.  I wonder if the new parks fund will ever have sufficient money to pry some of that away from the county.

They could have been cut by local gatherers hunting for Sorels and other such fungi.