Forest of Ae is forestry commision land and has a well signed car park for mtb called the '7Stanes' car park. The car park has a map on it. It doesn't have easy routes, just red and black. Details at www.7stanes.gov.uk. The red route is long and diverse. (19k) Lots of trees, a few granite drop offs and much to challenge you. But the true pearl is the last 3 miles of huge berms and jumps. The berms are 10 feet high in places. The jumps are similar and air is mandatory. Fantastic!