This Spring Trails Half Marathon is run in the Forest of Dean at the end of March, using the same organization (but a different course) as the Autumn event. Starting on the road adjacent to the Speech House Hotel in the heart of the forest, the course then leaves the road to follow a loop of well maintained forest trails (with gentle inclines) before eventually leading back to the Speech House Hotel for the finish.
This annual event is organised by The Rotary Club of the Royal Forest of Dean and supported by the Forestry Commission. Proceeds are used to support charities, both locally and nationally.

You can enter the event online here: http://www.forestofdean-halfmarathon.co.uk/spring_trails/index.php