Forest mortality due to fire and insect activity is already evident in the Northwest.
Continued changes in climate in coming decades are expected to increase these effects. Trees killed by a fire (left side of
watershed) and trees killed by mountain pine beetle and spruce beetle infestations (orange and gray patches, right side of
watershed) in subalpine forest in the Pasayten Wilderness, Okanogan Wenatchee National Forest, Washington, illustrates how
cumulative disturbances can affect forests. (Photo credit: Jeremy Littell, USGS).