Trees face threats as West Virginia celebrates Arbor Day
West Virginia will celebrate Arbor Day on April 9, this year, to recognize the importance of trees and forests to the life of the state.
Schools and organizations frequently plant trees on the holiday to beautify an area and teach civic responsibility. Organizations and groups that plant trees on Arbor Day often assume responsibility for the care of the trees and the areas where they grow.
According to the Arbor Day Foundation, 10,780 members planted 99,418 trees in West Virginia in 2010. The foundation has sponsored a state poster contest for the last 19 years, teaching students the importance of trees and wise environmental stewardship. In partnership with the Department of Forestry, the foundation sponsors 15 Tree City USA communities in West Virginia, where citizens and officials plant and care for trees to clean the air and water, beautify the community and save energy.
More than 62 percent of Pocahontas County is included in federal or state forests, helping to attract more than one million tourists to the county every year. Public and private forests in the county also provide a wealth of diverse hardwood lumber.
The diversity of local forests has never been more important than today, as natural threats are devastating a hardwood and evergreen species common in the area.
The American beech tree is being annihilated by a disease known as beech bark disease. The disease is caused by a tiny insect, known as the beech scale. The insects arrived from Europe by ship to Nova Scotia, Canada, about 1890. Since then, the insects and the disease have spread throughout the northeastern U.S. Beech bark disease was first discovered in West Virginia in 1981 and is now widespread in Pocahontas County.
The insect larvae, about a millimeter in length, feed on the tree bark and cause cracks in the bark. The insects secrete a white, waxy substance and dots of the wool-like wax on the tree are the first sign of the disease. Eventually, the entire bole of the tree can become covered with the waxy substance.
After the insects breach the bark, a nectria fungus invades and kills the tree. The dead tree is weakened by worms and woodpeckers and falls down. In residential or recreational areas, weakened trees are a safety hazard and should be removed.
Larger beech trees, eight inches or larger in diameter, are more susceptible to the disease than younger trees.
High value ornamental trees can be protected by insecticide spraying, but experts know of no way to control beech bark disease in forest conditions. Ladybugs eat the scale insects and a different fungus is known to be a parasite of the nectria fungus, but no cost effective method to control the beech bark disease has been developed.
In a once predominantly beech forest surrounding his Droop Mountain farm fields, Martin Saffer displayed the horrendous effects of beech bark disease. All of the mature American beech trees in the woodline were dead or dying. Fallen trees littered the landscape and ugly, broken boles were all that remained of once tall trees. Saddened by his devastated beech grove, Saffer said the importance of diversity in nature has never been more evident.
The situation is bleak for the American beech but not hopeless. The U.S. Forest Service reported that a small fraction of the trees are resistant to scale insects, offering hope that methods can be developed to increase resistance throughout forests.
As the American beech fights for survival against a European invader, the eastern hemlock is under assault from an Asian attacker.
Hemlocks are easily identified by examining the bottom of their needles. If the needles have two yellow stripes, it's a hemlock. If you find what looks like the tip of a cotton swab on the bottom of the needles, the tree is under attack from the hemlock wooly adelgid, an aphid-like insect. The cottony growth is the egg sac of the HWA.
The HWA is wreaking havoc on hemlocks from Georgia to Maine. Entire hemlock stands in the South have been destroyed. Cold weather kills the HWA and slows down infestations, but the insects reproduce rapidly and continue to spread.
The insect was first reported in the eastern U.S. near Richmond, Virginia, in 1951. Since then, genetic analysis has revealed that the insects originated in southern Japan. In Japan, the HWA does little damage because of natural predators and possible tree resistance.
The HWA sucks fluid from the base of hemlock needles and may also inject toxins into the tree as it feeds, causing needle drop and branch dieback. The defoliation eventually kills the tree, often in combination with other factors, such as drought or fungus infestations. Some trees die within four years, but some trees persist in a weakened state for many years.
Methods are available to protect hemlocks in your yard or in a nursery environment.
One of the best options is the use of horticultural oils. Horticultural oils are usually highly refined petroleum oils combined with an emulsifiying agent. Some plant-derived oils also are used. In order to be effective, the oil must be applied to the entire tree and might need to be reapplied a second time. It is essential to kill virtually all of the HWA on a tree or the population will soon reappear.
Another product providing good results is an insecticide known as Imidacloprid, which must be applied by licensed applicators. The insecticide can be fed to the tree via the soil or injected into the trunk. Imidacloprid is commonly sold in 1.6 ounce containers, which will treat up to 50 inches of tree diameter. A package of four can be purchased for about $150.
Once the HWA reaches any given area, it will constantly pose a threat to all hemlock, even those that have been treated. Therefore, all hemlocks in these areas should be monitored carefully several times a year and treatments applied when HWA is found. Wind and birds are the primary means for moving this pest from one tree to another.
The Arbor Day Foundation website includes an interesting history of J. Sterling Morton, the journalist who started the first Arbor Day celebration in Nebraska in 1874. For Morton's story and ideas how to celebrate the sylvan holiday, see www.arborday.org.