From A Wiki of Ice and Fire
Wat's Wood is a forest located in House Osgrey lands in the Reach. It is made up of oaks and pines. The west way, which runs from Standfast to Coldmoat, passes through the wood.
Wat's Wood once extended all the way to Coldmoat, but the forest was harvested to make way for grazing land and fields.
Wat's Wood burned during the long drought of King Aerys I Targaryen's reign, though the fire could have been started by members of House Webber, who had issues with House Osgrey. Ser Eustace Osgrey was surprised to find the carcass of a tree cat in the forest.