Monday, December 31, 2012
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Although it is only about the size of a period on this page, the hemlock wooly adelgid has singlehandedly wiped out many hemlock trees across the Southeast – and it won’t stop there.
“They are coming. They’re all around us,” says Bobby Davenport, trustee for the Lula Lake Land Trust. “Mortality rate is 100 percent... it’s devastated hemlock populations. It’s a slow moving catastrophe, but it’s a catastrophe.”
The invasive insect from East Asia can kill a hemlock in just a few years, sucking it dry of the nutrients it needs to survive. A sign of their presence is cotton-like puffs at the base of needles or small black dots the size of pepper flecks on the underside of branches.
With two generations produced each year, adelgids can quickly spread to new territory. Just two months ago, a group of Ivy Academy students discovered HWA feeding on hemlock trees about 45 hiking minutes from the school up North Chickamauga Creek. This was the first documented sighting of the insects in the North Chickamauga Creek Area. “The park rangers knew that it probably existed but they hadn’t found it on the North Chick Creek yet,” says Mary Bruce, a teacher at Ivy Academy. “Now that they have found it, they can treat it and save the tree.”
In the over 12,000 acres that the Lula Lake Land Trust protects, hemlocks are about 20 percent dominant.
The HWA hasn’t been spotted in the Lula Lake Land Trust acreage, but Davenport says it’s only a matter of time before the insect makes the “hop, skip and a jump” to the preserve spanning much of the Rock Creek watershed. “We just can’t stand by and do nothing,” he says. “Every hemlock will be dead in about a 10-year period of time.”
The land trust is next in line to receive a release of predatory beetles that eat the HWA, but Davenport says that alone won’t wipe out the insect. Arguably the most effective option for treatment is a pesticide, but because of the time and effort it requires to inoculate each tree, the process can be costly. “It’s very labor intensive to do that and you are talking about hundreds of thousands of trees. Exactly how much, we don’t know,” says Davenport. “We’ve protected over 12,000 acres. In those, about 20 percent of that acreage that the Lula Lake Land Trust protects is where hemlocks are dominant.”
The Lula Lake Land Trust is seeking donations to fund the inoculation, which Davenport says will begin as soon as the funding is secured.
For more information on Lula Lake Land Trust or to donate, visit lulalake.org
Why save the hemlocks?
The hemlocks aren’t just part of the South’s pretty scenery. In many cases, they provide an unbroken canopy, which shades the streams below from the sun.
If the hemlocks were to die and the canopy was broken, the heat would change the ecology of those streams, adversely affecting the many shade dependant species of flora and fauna that live there.