Fighting Hemlock Woolly Adelgid:
One Man's Plight to Save the Eastern Hemlock

By Élan Young

Throughout the southern Appalachian Mountains the eastern hemlock forests dominate many places in the landscape. They represent the largest (by wood volume), tallest and most common trees in places like Great Smoky Mountains National Park. Increasingly, the scenic overlooks there now offer vast views of dead giants. Hemlocks are in visible, massive decline - generating much public awareness, even though what the public is seeing is the impact of a crisis that has been mounting for two decades.

Devastation is caused by an Asian relative of the aphid, Adelges tsugae, hemlock woolly adelgid (HWA), a sap-sucking insect that set up camp in the southern Appalachians much more quickly than anyone could have guessed. It was first spotted on eastern hemlock in Virginia in 1951, and eastern North American hemlock forests provided a new frontier - no enemies in sight and a seemingly endless supply of food.

Twenty years ago, the HWA spread to Shenandoah National Park. By 1992, 95 percent of the hemlocks were dead. It continued to make its way north, up through New England, and south through the forests of the Blue Ridge; it was eventually discovered in the Smokies in 2002. Mild winters there fomented a population explosion. Now the subject of much anxiety for land managers, the HWA poses the single greatest threat to both eastern and Carolina hemlocks. It's even sparked fears that the two species could become functionally extinct.

But as the HWA spreads, so too does the effort to fight them. Scientists, arborists and land managers are among some of the people racing against time to preserve the hemlocks. Arborist and TCIA member Will Blozan is one of these individuals who has lately made saving the hemlocks the cause of his life.

Blozan regularly ascends some of the tallest and largest old-growth hemlocks in existence. Climbing from the forest's darkness into the open, airy canopy offers him a friendly perspective. It's sunnier, with endless views of sky and mountain, where hummingbirds might survey his red climbing gear with curiosity. Over the years, the biggest and tallest trees have become his specialty. When it comes to hemlocks, he's downright obsessed.

"There's something about these ancient trees that's inexplicable to humans," he says.
In 1993, one year after Shenandoah's tragedy, Great Smoky Mountains National Park hired Blozan to assist with surveying the park's hemlocks and prepare for the arrival of the HWA. For three years he worked among these trees, developing a deep appreciation for the species. Along the way he developed a talent for finding champion trees. To date, Blozan has contributed some three dozen champions from over 15 species to the American Forests National Register of Big Trees. After leaving the park service, Blozan took his knowledge of trees to the private sector and started Appalachian Arborists, Inc., a tree service in Asheville, N.C., specializing in HWA management. In his spare time he shares his passion with other tree enthusiasts by serving as president of the Eastern Native Tree Society, an online community (www.nativetreesociety.org) primarily dedicated to finding the biggest and tallest trees of the East. (The acronym is ENTS, named for the enchanted trees in J.R.R. Tolkein's Lord of the Rings.)

By 2005, Blozan could see that the die-offs were going to be massive. Unable to sit idly by, he poured himself into a project of historic proportions: finding, climbing and measuring the 15 biggest and 15 tallest eastern hemlocks before they perished. He didn't want to see them go the way of the American chestnut, which, until it was obliterated by a non-native fungus in the early 1900s, had probably been the most common tree in the southern Appalachians. Yet no historical records remain for what that species was capable of in terms of height and mass. Blozan knew that if he couldn't preserve the hemlocks, he could at least preserve their data. To him, it was a matter of historical record. His seven notebooks worth of information might one day prove useful for hemlock restoration.

The project, named the Tsuga Search Project (Tsuga being the Latin genus of hemlock), was grueling and expensive, costing his company about $100,000. The quest for superlatives took him to five states, but not a single hemlock outside the southern Appalachians was over 160 feet. Prior to the Tsuga Search, the tallest known hemlock was 169.8 feet tall, another one of Blozan's height champions. (Most guidebooks describe hemlocks' maximum height at 150 feet.) By August 2007, 21 months after the project started, his team wrapped up their findings. They had climbed and measured over 9,300 feet of hemlock in some of the most remote reaches of eastern wilderness. The results clearly made his vision worthwhile. Not only did they find hemlocks that broke height and volume records, but they also engineered methods for determining tree measurements more accurately.

Walking through the woods looking for big trees is as much an art as a science. Blozan and his project partner, Jess Riddle, used a laser rangefinder and clinometer for an initial measurement before deciding if it was worth climbing for a more accurate reading - dropping a tape measure down from its top. Even from the ground, they can estimate a tree's height with amazing accuracy, which is how during a lunch break they found the first hemlock ever recorded measuring over 170 feet. Of the many hundreds they measured, only three others were found in this height range; the tallest, 173.1 feet.
The team used a park soils map to find the bedrock that Blozan and Riddle suspected was helping produce the tallest specimens, which led them to new finds in the Cataloochee, N.C., district of the Smokies. They searched every outcrop before finding the holy grail of tall trees. That day they found seven superlatives. Every cove had something in it - super-tall tuliptrees over 170 feet and red maples over 140 feet.
"There's no other place in the east with this much density and height," says Blozan. The finding secured Cataloochee as the modern day "epicenter" of the tallest hemlocks in the world. But the find was bittersweet - many of the hemlocks were too far gone. "Had we done the study earlier, we could have saved them all," he adds.

Out of the four tallest hemlocks on record, only one remains alive. Of the 30 record-breakers for height and wood volume, six are alive, but only three appear healthy enough to survive. (They have been treated with insecticides - more on that later.)
For all of Blozan's efforts to keep the hemlocks in the spotlight, he has attracted a lot of attention to himself. Reclusive by nature, Blozan seems more comfortable listening than speaking. But as the publicity increases, he willingly takes the mantle of speaking for the trees from whatever stage he can. In addition to local articles and presentations, his work has been featured in The New Yorker and Wall Street Journal. Now, he's being filmed for a documentary about the hemlocks, a project begun through a friendship and fueled by a shared sense of purpose.

The documentary, entitled "The Vanishing Hemlock: A Race Against Time," is currently being filmed in Great Smoky Mountains National Park. Filmmaker David Huff is currently raising funds for the project and hopes to have it completed by the end of the year and distributed by spring of 2009. It's a project that developed as much from Huff's friendship with Blozan and knowledge of his work as from his own interest in the hemlocks' fate.

"I've spent a great deal of my life hiking and camping in these woods and the loss of these trees is personal," he says. Blozan helped make the issue personal when he showed Huff a picture of one particular tree in massive decline - a tree they had climbed together years before when it was lush and full.

Whereas Blozan's mission is raising awareness for the hemlocks by sharing information, Huff's mission is to let people participate visually and emotionally in a changing landscape. He does this by following his friend into the woods and up the trunks of the world's largest hemlocks, and by filming from a rare vantage point that only birds, helicopter pilots and some arborists can regularly appreciate.

As a filmmaker, Huff knows the power of images. He knew that others would be moved if they too could witness the devastation up close. Instead of raising money for the cause, he felt his biggest contribution would be to reframe the issue on a larger screen, shifting the story from the ground to the canopy.

The response from land managers who've seen pre-production footage from the film hints at its potential impact. The room often gets quiet when shown the aerial footage over Cataloochee, an area of Great Smoky Mountains National Park described by Blozan as the "Valley of the Giants." But when it's over, there's clamoring to get the film distributed widely, and soon. It offers a new perspective for anyone, perhaps most importantly those most intimately involved in saving hemlocks. (To learn more about this project and/or to make a tax-deductible contribution, visit www.thevanishinghemlock.com)

Saving individual trees
For all the attention that Blozan has helped bestow on the hemlock crisis, his work is not without heartbreak and frustration. As more information about HWA reaches the mainstream, there's also been an increase in misinformation. For private property owners, confusion reigns about how to protect their investment of trees. Since it costs far more to cut down a dead tree than it does to protect it with insecticides, many landowners have fallen prey to unethical tree care companies wishing to make a quick buck.

A recent heartbreak occurred just outside of Asheville, N.C., where Blozan had been keeping an eye on a healthy hemlock grove in an old churchyard - trees that were planted circa 1820. He wanted to leave the church a note about his services, but the next time he passed, the trees were gone. Someone had convinced the church that trees were dead and it would be better to cut them down than to treat them. Blozan could have treated them with about $300 worth of insecticides.

The standard treatment for HWA-infested hemlocks is with imidacloprid. For years it has been the short-term means of killing the HWA, and studies have shown it to be effective without compromising the environment. In 2005, it was approved for backcountry forestry use. Even so, Blozan is seeing that its slow uptake is nearly ineffective on large, heavily-infested trees over 30 inches in diameter.

Blozan points to current research that says that any hemlock over 32 inches diameter is under-dosed when treated with current imidacloprid dosage rates. "Some of the largest trees are probably only getting one tenth the dose [of imidacloprid] that they need."
Blozan, who's worked with HWA since 2001 and has been a big proponent of proactive imidacloprid treatment, has recently seen great promise from a newer chemical made by Valent called Safari (dinotefuran). It's a solution 80 times more water soluble than imidacloprid and can translocate into the needle within days, essentially giving heavily infested hemlocks a new lease on life.

Blozan is hoping that Valent will be able to set up research plots in the Great Smoky Mountains National Park, where HWA is killing trees at an alarming rate. Desirable results could allow Safari's label to include forestry use.

Private property owners are understandably fearful about HWA. For the hemlock, the cycle of death is quick: first the needles fall off; then the adelgid population crashes. The tree tries to recover by sprouting new needles, and the tree becomes re-infested. Without intervention, a fully infested tree can literally starve to death within five years, during which time it will turn a grayish-green color.

Scientists are also fearful, knowing that the loss of the hemlocks could be even more ecologically disruptive than was the loss of the American chestnut. The chestnut left gaps that were eventually filled in with other hardwood and nut producing trees. In the southern Appalachians, no other native evergreen exists to fill the specialized niche of the hemlocks.

In some ways, arborists are perhaps most uniquely positioned to educate land owners about HWA and the best available treatments, as well as to dispel myths from predatory tree service companies.

Whether from the pest itself or the slow human response to treating against HWA, Blozan has had many frustrations in his work. A realist, he's not always hopeful about the overall fate of eastern hemlocks, but he remains firmly committed to the task at hand: saving one tree at a time.