OLYMPIA, WA (MyBellinghamNow.com) – An annual report from the state Department of Natural Resources (DNR) shows concerning tree mortality rates not seen in over 50 years.

The Forest Health Highlights report comes after a 2023 aerial survey of over 22 million acres of Washington forest. At over 517,000 affected acres, it is the lowest number since 2018.

The researchers said the most concerning datapoint from the study involves the Douglas-fir Engraver beetle, which are damaging trees at a level not seen since 1969. They added that this is a significant increase since 2019, up nearly 20% from 20,300 affected acres.

The beetles are classified as “secondary bark beetles” which denotes that they take advantage of trees that are already stressed from other factors such as heat and drought. There are two other species of bark beetles, and all three species are not typically the primary cause of tree deaths.

The report also surmised that excess heat and drought is responsible for bringing the first known appearance of the California Fivespined Ips beetle into western Washington in 2022, whose numbers have only expanded since. The DNR said the cause of the higher mortality rate is not determined, but the ongoing issues with drought and heat in the area could affect the trees to the point where it is hard to recover in cooler, wetter years.