Following the loss of thermal activity the pilot elected to land in a paddock where the 5-10 knot wind would produce a right crosswind and downwind component for landing. During the base leg, which was commenced from a low height, the pilot realised that his groundspeed was high. The turn to finals was conducted at 60 knot indicated airspeed and up to 45 degrees of bank to avoid overshooting the final path. Dive brake was applied during the turn to increase the glider's descent angle but the glider stalled. During the recovery the glider collided with trees.