Unmanaged and Treated Forests (IMAGE) University of Washington Caption Left: A forest site in north central Washington that has had no known thinning or burning treatments. Right: A forest site that was previously thinned and burned. Large, fire-resistant ponderosa pine trees dominate this area, with very little flammable ground debris such as shrubs, grasses and downed wood. Credit Susan Prichard/University of Washington Usage Restrictions Credit required. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.