DCNR tries to protect state trees from killer insect species

Local News

CLEARFIELD COUNTY, Pa. (WTAJ) — A dangerous insect responsible for killing thousands of acres of hemlock in North Carolina has recently posed that same threat in our region. If untreated, this invasive species will likely kill all eastern hemlock trees it comes in contact with.

The hemlock woolly adelgid attacks the eastern hemlock, Pennsylvania’s state tree, by piercing it’s needles and feeding on the nutrient-rich fluids inside, causing the needles then turn yellow – as well as develop cotton-like egg masses before dying. The invasive species has spread from eastern Pennsylvania, to the western part of the commonwealth over the past two decades.

To avoid significant loss of hemlocks, which would be devastating for the environment, foresters say. Due to the many forms of wildlife that use the trees as a vital source of shelter and food, including , the state fish, the brook trout. The DCNR has developed a Hemlock Conservation Plan built around treating the state tree to avoid infestation, by treating the trees with insecticide.

Students at Penn State DuBois have partnered with the Pennsylvania Department of Conservation and Natural Resources (DCNR) to help protect hemlock trees from an invasive insect species.

The Biology 220 students made a visit to Bilger’s Rocks Recreation Area near Grampian where they treated 79 Eastern hemlock trees with insecticide to protect them against the hemlock woolly adelgid, an insect that originated in Asia.

Penn State DuBois Lecturer of Biology Lola Smith began bringing her students out to participate in this project in 2019 but was unable to in 2020 due to the COVID-19 pandemic. Smith says students helped treat nearly 200 hemlock trees between 2019 and 2021.

“This gives them hands-on experience, as well as experience with forest ecology and health,” said Smith. “They also get to see what is involved in jobs in forestry and other careers they might be interested in.” 

The DCNR says the hemlock woolly adelgid is a serious threat to hemlock forests in the state where the insect has been located in 64 out of 67 counties.

“It’s a serious threat. In North Carolina, the insect has destroyed thousands of acres of hemlock forest. We’re concerned that could happen here,” said DCNR Service Forester Rick Conrad.

“Without treatment, they will die, the trees will die,” said Mark Faulkenberry, DCNR chief of program services in the Bureau of Forestry. “It’s basically worked its way over to the Ohio border. There are only three counties in Pennsylvania that we don’t have reports of Hemlock Woolly adelgid.”

The insect infests and kills hemlocks by piercing the tree’s needles and feeding on the nutrient-rich fluids inside. Infested trees are identified by yellowing needles and cotton-like egg masses on the underside of the needles.

Foresters say the loss of hemlocks would also negatively affect the environment by depriving many forms of wildlife of shelter and food including fish. According to DCNR, the hemlock woolly adelgid was first discovered in the United States in Virginia more than 50 years ago. It has since spread to 17 states including Pennsylvania.


The Eastern hemlock was officially named Pennsylvania’s state tree in 1931 due to its prominent presence in forests across the commonwealth as well as the resources it provided for early setters building cabins.

Additional information about state conservation efforts is available on the DCNR website.

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