Along with other factors, insects act as important disturbance agents in Utah forest ecosystems.

Douglas Fir Beetle

Bark beetles and balsam wooly adelgids are two insects causing extensive damage to trees across Utah. They can wipe out entire forest stands, as is evident across many portions of the Wasatch and Uinta Mountains.

Sap exuding from a Douglas fir

Trees can defend themselves by producing sap to deflect these insects as they lay their eggs below the bark. However, sap production is reduced under drought stress.

Click here to read the state’s latest report.

Egg and larval galleries of Douglas-fir beetle

During droughts, trees produce less sap and become more vulnerable to beetle attacks. Eggs and larval galleries lie just below the bark layer.

Among the first signs of this insect damage are the appearance of brown needles, followed thereafter by needle drop and eventually tree death.

Climate change is making Utah’s forests more susceptible to insect damage. Climate changes underway now are resulting in warmer winter, resulting in less over-winter death of these insects. As a result, insect damage increases and forest health decreases.

Dr. Barbara Bentz is one of the world’s foremost specialist in bark beetles.

Click here to see a video of Dr. Barbara Bentz at Utah State University talking about her research on bark beetles and what inspired her to become a research scientist.

Click here to learn more of Dr. Bentz’s current research.