ANF silviculturist says ‘we’re trying something’ to combat emerald ash borer killing spree on ANF

Emerald ash borer continues to devastate populations of ash trees.

The Allegheny National Forest first established a strategy to prepare for the invasive species back in 2006.

Since it was first confirmed on the ANF in 2013, EAB has been killing trees. It is estimated that mortality — all ash species — will be 80 to 100 percent within 15 years.

There are some measures underway to mitigate the damage.

Parasites have been released on a small scale.

Insecticides have been used in some trees.

Whether those measures work or not, the experience will help scientists in other areas develop plans to save trees.

“We’re trying something,” ANF Silviculturist Andrea Hille said. “If anything, let’s learn. Maybe it will benefit other places. Maybe it will benefit us.”

Some trees in Ohio are lingering through the EAB infestation. That gives scientists the hope that there is some particular immunity that could be bred into the species.

If nothing else, officials are preparing to repopulate by gathering seeds.

“The key thing is to get the seed collected and stored,” Hille said.

“It is looking to be a good year for ash seed collection,” she said. “It would be great to try to collect a little more ash seed for long-term storage at the National Seed Laboratory before we lose our remaining ash and that opportunity.”

Individuals who are interested in seed collection may contact Hille at

The same email address works for those who have identified “lingering trees” that survive waves of infestations. In addition to ash trees, the ANF is interested in American beech, American chestnut, butternut, and eastern hemlock. Hille can provide information about how to submit information about lingering trees.

About 2.5 percent of the trees on the ANF are ash, according to Hille. That’s an estimated 1.5 million ash trees.

Without serious protection, there are three options for most ash trees — cut now, cut later, or let it fall. Trees killed by EAB become hazard trees, Hille said.

The ANF’s Forest Health Collaborative is working with estimates that 80 percent of ash trees killed by EAB will fall or break within five years.

In August, the Pennsylvania Bureau of Forestry released four different species — about 4,600 individuals — of parasitoids that feed on the eggs or larvae of EAB. Hille described the parasitoids as small and wasp-like — about the size of a sweat bee. She said they do not sting humans. The results of that effort are expected to be very localized to the area of Pleasant Township where the parasitoids were released.

In many areas of the ANF, ash trees are spread far and wide, making preservation and harvesting efforts difficult or less meaningful.

In some places, they have grown in groups. The Bradford Ranger District has undertaken an ash remediation effort in one of those places. The ash throughout the 3,000 remediation area are being cut and a more diverse mix of trees is being planted to reforest the area.

Insecticides were applied to trees in 2015. Groups of about 20 trees in 27 different areas were protected “to conserve “spatially and genetically diverse germplasm and seed.”

Another 131 trees were treated with insecticide the same year at 13 developed recreation areas.

ANF staff plan to retreat 509 trees on 21 plots and 137 recreation area trees this year.

Individuals and municipalities that do not plan to protect their ash trees may be well served to look to sell them. Or, at the very least, make an arrangement to exchange the trees for the work of cutting them.

Ash is used in flooring, cabinetry, handles for tools, and sporting goods including hockey sticks, pool cues, oars, and baseball bats. “It’s a very nice, straight-grained tree,” she said. “We have been salvaging ash.” So far, “it’s been holding it’s value.”

The invasive species is spreading.

EAB is a “strong flyer,” according to Hille, but it didn’t go from Ohio and Michigan to Colorado on its own. She said primary movement of EAB is through firewood. When a person takes firewood from an area where EAB is present to an area where it is not, the species can tag along and be introduced.