Gypsy Moth Defoliation on the Increase

Gypsy moth defoliation in Virginia this year has been estimated at over 112, ooo acres, an increase of 46% from last year. The most heavily impacted area was the GW National Forest in Augusta County extending into southern Rockingham County, which, combined, saw almost 43,000 acres of heavy defoliation. Another heavily impacted area for the third year in a row was northwestern Giles County, where more than 15,000 acres of forest was defoliated, most of that being in the Jefferson National Forest.

Gypsy moths were introduced into the United States via Massachusetts in 1869 and have been slowly spreading southward ever since. The first defoliation in northern Virginia was recorded in 1984 and the moths continue to spread slowly southwestward.

Dry spring weather predominated during 2005-2007, helping populations of gypsy moth to build up. This May, however, it was cool and wet at the right time, which can foster the development of a fungus disease affecting the moth population.

“In some areas, caterpillar mortality from disease appears to be quite high,” say VDOF Forest Health Specialist Dr. Chris Asaro . “The caterpillars die only when they are nearly full grown and most of the defoliation is done, so the disease doesn’t have much of an effect for this year. On the other hand, dead caterpillars mean fewer adult moths will be around this summer to lay eggs. So, next year’s defoliation could be considerably lower.”

Egg mass surveys will be completed in late summer and fall and will give a better idea of what can be expected next year.

For more information visit one or more of these sites:

VDOF Forest Health Site

VDACS

Virginia Tech Gypsy Moth Site

Appalachian Fire Learning Network

Scientists and managers from state agencies, the US Forest Service, and The Nature Conservancy (TNC) met July 8th -10th at Douthat State Park for the third workshop of the Appalachian Fire Learning Network (FLN). Hosted by the Alleghany Highlands FLN project, the workshop focused on collaborative efforts to restore forest communities dependent upon fire. Representatives attended from the three other demonstration projects in the network: Cumberland River, KY; Shawnee Forest, OH; and Southern Blue Ridge, NC. Each project reported on their planning efforts and accomplishments.

A highlight of the workshop was of course the field trip. We visited recent prescribed burns conducted by two Alleghany Highlands FLN partners, the Forest Service and TNC. Together both partners burned over 4,000 acres last year to restore pine and pine-oak woodlands. We also visited a globally rare “pine barrens” variant of the pine-oak/heath woodland communtity on Warm Springs Mountain. The challenges of restoring this fire-dependent community (likely a stand replacement regime) were a topic for much discussion.

Collaborators in the Alleghany Highlands project include TNC, USFS, Virginia Department of Forestry, Virgina Department of Game and Inland Fisheries, Virginia Department of Conservation and Recreation, and Shenandoah National Park.

More information on the Appalachian Fire Learning Network can be found at
http://tncfire.org/training_usfln_appsfln.htm.

Emerald Ash Borer Infestations Found in Fairfax County, Virginia

On July 7, 2008, an infestation of the emerald ash borer was discovered in dying ash trees by Andrew Brown, VDOF forester for Halifax County, while visiting family in a residential development in Herndon, Va., near the Dulles Access Road. Two days later, another infestation was discovered on the other side of Fairfax County in Springfield, just west of I-95. Both infestations appear to have begun some years ago, indicating that the wood boring insects, which have a one-year life cycle, have likely spread to many other areas. Eradication measures for this insect pest will, therefore, be very difficult to implement.

Officials from the Fairfax County Forest Pest Program, Virginia Department of Agriculture and Consumer Services (VDACS), Virginia Dept. of Forestry, and many others, are actively searching for more evidence of infestation in Fairfax and adjacent counties. VDACS will likely soon issue a quarantine that prevents all ash material from leaving Fairfax County. Additional counties will likely be quarantined as well if and when the borer is discovered there.

The emerald ash borer is a highly destructive invasive species that has already killed millions of ash trees in Michigan and Ohio and may, ultimately, cost billions of dollars in tree removal and replacement costs. Since its discovery in 2002 in the Detroit area, it has spread to seven additional states (Ohio, Illinois, Indiana, Pennsylvania, Maryland, West Virginia and Virginia). It is also found in Ontario, Canada.

While it spreads at the rate of about two miles per year on its own, this wood-infesting beetle can be moved great distances by human transport of infested wood products, particularly firewood. Firewood for sale in Virginia is brought in from many different states, and many out-of-state travelers bring firewood with them to go camping throughout Virginia’s state and federal lands. Most new infestations have been located either near campgrounds or adjacent to major interstate corridors.

All species of ash trees of all ages, sizes and relative health are vulnerable to the emerald ash borer. The insect is usually very difficult to detect because ash trees typically don’t show any obvious signs of infestation until one year or more after the insect has attacked the tree. By then, the insects will have moved on to attack other trees. Traps for monitoring the insect are available and have been widely distributed by VDACS. However, these traps are not attractive to the beetles from long distances and, therefore, aren’t highly effective for early detection and for precisely locating infested areas. Research for improving these monitoring tools is ongoing.

The only control measure available is to cut and chip infested trees. An effective systemic insecticide for individual tree protection has recently been approved and may be widely available within a year, but this will be very expensive and not practical for halting the progress of the insect. Over the long run, homeowners and municipalities should consider replacing ash trees with other species that are not susceptible to emerald ash borer. It is highly likely this pest will eventually become established across Virginia, although government officials, pest specialists and arborists will work together to limit and/or slow its eventual spread.

For more information on what you can do to abate the threat of exotic pests such as the Emerald Ash borer visit the Don't Move Firewood website

Virginia’s 8th Forest Survey Shows Loss of 128,000 acres

Data collected in the five years, 2002 to 2007, by Virginia Department of Forestry forest inventory crews has been analyzed and summarized by the US Forest Service as Virginia’s 8th Forest Survey.

Since the last survey published in 2002, there has been an estimated net loss of forest land of nearly 128,000 acres. Forests now cover 15.7 million acres of Virginia’s 25.4 million acres, according to the survey. With an average plot re-measurement period of 5.2 years, the net loss was at an annual rate of 25,000 acres per year, up from 20,000 acres per year in the 7th survey.

Despite the loss of forestland, positive net growth on the remaining acres has increased the total biomass by 50 million dry tons and total growing stock wood volume by 18 million cubic feet. Therefore the amount of carbon stored in Virginia’s forests has increased by nearly 6%.

Despite the loss of trees to gypsy moth defoliation, hemlock wooly adelgid, southern pine beetle and hurricane Isabel in 2003, mortality rates were lower during the 8th survey period than the previous survey period.

Regional differences in forest land loss, growth and mortality exists across Virginia and these will be addressed in future posts. If you would like to explore the 8th survey data further you can visit the USFS Forest Inventory data website for more details.

Breeding American Chestnuts for Restoration

It that’s time of year again - time to backcross chestnuts as part of the Department of Forestry’s American chestnut restoration program. At the Department’s Lesesne State Forest in Nelson County foresters bagged flowers on the first- and second-backcross trees we having growing there. The backcross trees were created by making hybrids with the blight resistant Chinese chestnut, and then pollinating the hybrids with pure American pollen. The resulting first-backcrosses were grown and then pollinated with American pollen for the second-backcross. The first-backcrosses are the trees shown in the pictures with bagged flowers.

In the next couple of weeks we will be pollinating these flowers with pollen collected from surviving American tress. The resulting nuts, and trees raised from those nuts, will be chestnuts with roughly 7/8’s or 15/16’s American genes.

The ultimate goal of these efforts is a population of chestnuts with predominantly American characteristics with blight resistance as strong as that of the Chinese chestnut. This population of chestnuts could then be used to restore chestnuts to the Virginia forest landscape.

The backcrossing work is being led by Research Forester Wayne Bowman, with assistance form various volunteers from the Department of Forestry staff. The Department, under Wayne's leadership, is also raising backcross seedlings from the American Chestnut Foundation's Meadowview Farm, and has established backcross plantings at Matthews State Forest near Galax.

Forest Health Review - Spring 2008

The current issue of the forest health review provides a detailed description of last years southern pine beetle activity as well as forecasts for this years southern pine beetle and gypsy moth activity. Also, updates on emerald ash borer, beech bark disease, the ‘Don’t Move Firewood’ campaign, and the Early Detection Rapid Response Program. An article on suburban forests details the problems posed by high deer densities and invasive species.

The full report can be downloaded at:

http://www.dof.virginia.gov/health/publications.shtml#ForestHealthUpdate

Effects of Establishment Methods and Initial Seedling Size on Early Northern Red Oak Performance

In early 2006 the Virginia Department of Forestry installed a test of the effects of different establishment methods and initial seedling size on northern red oak survival and growth. There were two old-field locations, one in Louisa County and the other in Washington County.


Northern red oak seedlings from the DOF’s Augusta Forestry Center were graded into three root collar diameter classes – small (0.2 inches), medium (0.3 inches), and large (0.4 inches) and planted in early March 2006 using one of five establishment treatments: 1) no treatment; 2) VisPore mulch mat plus 4-foot Tubex tree shelter; 3) spot spraying of a 2-ft radius spot using a 2% glyphosate solution; 4) 4-foot Tubex tree shelter plus 2-ft radius glyphosate spot spraying; and 5) VisPore mulch mat only.

After two years, all the trees are off to a very slow start. Even the best of the seedlings have grown only about 1.5 feet in height and 0.06 inches in groundline diameter (GLD). But it looks like the way they are established (i.e. in tubes or not) has a lot more to do with their performance than does their initial size. And it seems as if the seedlings in the tubes are spindly - although surviving better and growing in height, they aren’t growing as much in GLD.

Comparing establishment treatments shows that the Tubex shelter was essential for survival / browse protection.

The VisPore mat and spot herbicide treatment resulted in similar survival and growth. There was no effect of initial seedling size on survival. The smallest seedlings have grown less than medium or large seedlings.

Without protective shelters, most of the seedlings in the study are either dead or in the severely browsed condition seen at left.