Bark beetles, engravers and other pests can invade and cause damage to forests across the United States. In Washington, our Douglas-fir trees are susceptible to a variety of wood boring pests. Luckily these pests are treatable. Pests mostly affect unhealthy, sick and declining trees, but generally healthy trees can be affected in the right conditions. Bark beetle pest treatment is a 3-5 year treatment plan best accomplished in cooperation with a Forest Management Plan or Forest Stewardship Plan.