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Tree-Killing Insect Threatens Hocking Hills Skyline


It’s been a tough decade for Ohio’s trees. The Emerald Ash Borer is killing millions of ash trees. Now another insect threatens a key tree in Ohio’s picturesque Hocking Hills. The Hemlock Woolly Adelgid attacks and eventually kills Hemlock trees. The state of Ohio is fighting back. Hocking Hills, a popular destination for hikers, campers and tourists, many people don't necessarily realize the area owes much of its beauty to Hemlock trees. Rebecca Miller, head of the Hocking Hills Conservation Association, says a Hemlock forest is unique. “It’s cool, it smells good, the birds that are in there are really unique, it’s just a unique type of ecosystem. And that’s why I like Hemlocks,â€? Miller said. Glaciers from the far north brought the Hemlocks to Ohio. The evergreens thrive in the rocky soil of the Hocking Hills. But the trees are under attack. A small insect, the Hemlock Woolly Adelgid is the culprit. “The Hocking Hills region has by far the largest concentration of, the most acreage of Hemlock in Ohio,â€? said David Apsley, a natural resources specialist with Ohio State University Extension. “Cantwell Cliffs, which is part of the Hocking Hills State Park system ... this is where we found Hemlock Woolly Adelgid about a year ago, real close to this date,â€? Apsley said.


The tiny insects are found in white, cotton swab-like sacs. They attach to and feed on the Hemlocks’ needles. “It has like a sucking mouth part. It puts like a stylus into the base of the needle and when you get really high concentrations of these adelgids they essentially just sap the energy out of those trees and the tree will decline and die. It can be anywhere from a couple of years to 10 years before mortality,â€? Apsley said. An invasive species The adelgid or HWA, as it’s called, came from Japan. Officials first discovered the insect in Marietta, Ohio several years ago in a Hemlock that was part of landscaping. Now the HWA is spreading north. Needless to say wide patches of dead trees are not good for the Hocking Hills core industry. “Tourism is a huge thing down here in Hocking County. It’s kind of what keeps our county afloat. Economically HWA could have an impact so we decided that it would be in our best interest if we fight HWA the best we can and preserve what we have down here,â€? Miller said.


State conservationists contacted foresters at Great Smoky Mountains National Park which had fought a losing battle with the HWA. “We knew that we would only be able to save a fraction of the Hemlocks,â€? said Kristine Johnson, head forester at Great Smoky Mountains National Park. Johnson said the HWA struck after a similar insect killed most of the park’s Frasier Fir trees in the 60’s, 70’s and 80’s. “That was already a scene of devastation that was shocking and devastating for people to see and now from Clingman’s dome you can look out past the dead Frasier Fir trees to the lower elevations and see thousands of acres of dead Hemlocks,â€? Johnson said. But the Smokies did manage to save whole sections of Hemlocks through a variety of methods. Foresters used chemicals to treat trees. They also released adelgid-eating insects. How to rid the problem


Hocking Hills conservationists are using those same methods. Great Smoky Mountains Forester Jesse Webster says Ohio is in a good position to save a lot of the state’s Hemlocks. “They’ve got a leg up on what we’ve already learned and they’ll be able to use a lot of our tricks to get the best bang for their buck,â€? Webster says. While they are not native to Central Ohio, Hemlocks are a popular landscaping tree. They provide beauty, shade and privacy. “People just basically like the looks of them,â€? says Alfred Barnett, general manager of Straders Garden Centers.


Barnett says people should familiarize themselves with the appearance of HWA. “We know this is a bad insect. We know that it’s going to devastate the wild Hemlocks. We’ve already seen it in certain areas. There are hundreds of thousands of Hemlocks out right now in the state of Ohio so let’s teach people how to prevent this insect,â€? Barnett says. So if you have a hemlock or if you’re hiking in the Hocking Hills, be on the look-out for the Hemlock Woolly Adelgid. Contact the Ohio Department of Agriculture if you see it.