In reply to Tom Tushaw:
Glen Nevis has nice birchwoods and Dunkeld is in mature forest.
Black Crag in Troutdale is beautiful with Quayfoot, Bolderstone and Wodens nearby.
The low level Dartmoor crags are in incredible, twisted dwarf oak forests.
I grew up in the Foest of Dean climbing in the Wye Valley, so generally think of woodland crags as dank, slow drying, insect infected places, so it's good to be reminded of their finer points!