Forest Health Monitoring Review
December 2003

Weather
Bark Beetles
Gypsy Moth
Other Defoliators
Invaders
Shorts
Fast Talkin Boy
Falcata Fix

Health Watch
Health Watch

Health Primer
Climate Change
Solitary Wasps

Health Update

Weather - Although January was relatively dry in most places, the rest of the year has been wet. February was roughly twice as wet as normal. March ranged from 65% of normal precipitation in the Southwestern Division and about normal in the Central Mountains to 141% of normal in the Eastern Piedmont. April ranged from 107% normal in the Northern Division to 196% in Tidewater. May was 130-209% of normal; June and July averaged 145% normal. August ranged from 109% in the North to 156% in Tidewater. September was 122% of normal in the Southwest, at least twice-normal everywhere else and essentially three-times normal in the Eastern Piedmont!! Many rainy day records have been set.

Temperature was more variable. January and February were cold, March was warmer than normal by an average of 2.8 degrees, and April was about normal everywhere. May ranged from 2.8 degrees above normal in the Southwest to 5.8 degrees below normal in the Western Piedmont. June was quite cool, from 2.1 degrees below normal in Tidewater to 5.3 degrees lower in the Western Piedmont. July was a degree warmer than usual in Tidewater and cooler elsewhere, up to 2 degrees cooler in the Western Piedmont. August was warmer than normal in every Division, up to 2.6 degrees warmer in Tidewater. September ranged from 1.4 degrees warmer in Tidewater to 2.3 degrees cooler than normal in the Western Piedmont.

The April issue covered winter storms. Since then, we've had plenty of additional impact. Some high elevations sustained a late spring freeze that affected emerging foliage and caused confusion during aerial defoliation surveys. On May 5, there was an earthquake (3.9) in central Virginia near Columbia that fortunately caused little damage. On May 9, an extraordinarily powerful storm tore a several-mile wide path from Albemarle County southeast through Southampton and into North Carolina. Straight-line winds of nearly 100 mph, two tornadoes and phenomenal hail caused extensive and severe damage. High quality timber was broken and uprooted in Albemarle, Amelia lost large trees in its court square and for several miles southeast of town, Southampton County sustained major damage to forests and structures from huge hail stones (up to 3 inches or more) blown by high winds. Large areas of pine were killed by loss of growing tips as well as foliage in combination with heavy bark damage. Scattered wind and hail damage occurred along the full path of the storm, affecting parts of 8 or more counties. At least one commercial tree nursery was also heavily damaged.

Flooding in May was widespread and damaging, including human fatality. Many records were set for numbers of rainy days. Woodstock, which is normally one of the driest areas in Virginia, had 23 rainy days in May - 5 more than the previous record set in 1953. Many more precipitation records have been broken since May and local flooding has been a recurring problem. On July 9, a tornado hit in Loudoun County, hail was reported in Bedford and Franklin and winds up to 60 mph caused tree damage and power outages in Richmond and surrounds. On August 26, a hailstorm and possible tornado hit near Richmond, hail and wind damage was reported from Loudoun, Westmoreland and Middlesex and wind damage affected parts of Fairfax and Arlington. The next day a large tent collapsed on Albemarle County fairgoers during driving rain and gusty winds. On September 2nd, strong winds and up to 6 inches of rain caused flooding and power losses around Charlottesville, and hail with damaging winds hit Madison, Stafford, King George and Rockbridge. All this was just the opening act for hurricane Isabel, which roared through on September 17 and 18, leaving behind a huge tangle of downed trees and power lines that kept some folks without electricity for two weeks or more. Tree damage was worst in southeastern counties, but extended northwest into the Piedmont and northern mountains. Shortly after, on September 23, a tornado tracked from Nottoway County northeast through Amelia, northside Richmond, Henrico, Hanover, King William and into the Northern Neck causing additional severe damage and power outages. Total timber losses were estimated by John Scrivani to be $176,760,303 based on average value per acre and estimated percent loss by county.

On October 7, at the request of the Virginia Loggers Association, Governor Warner authorized a temporary waiver of registration, license and weight restrictions for logging trucks operating in hurricane affected counties.

Bark Beetles - A long-lasting southern pine beetle outbreak in the southwestern mountains collapsed over the winter. Persistent low-level populations on the Appomattox-Buckingham and Cumberland State Forests threatened a potential increase that fortunately never materialized. Storm damage gave Ips beetles an opportunity this spring, but they failed to take full advantage of it. Even turpentine beetles did not seem to be as prevalent as they have been for the past several years.

With the pressure off we are able to concentrate more on prevention and restoration efforts supported by USFS, Forest Health Protection. A new brochure entitled Protecting Your Pine Forest was recently distributed to each Region. It encourages appropriate planting, thinning and harvesting to maintain pine forest health. We have also been restoring beetle damaged stands on the State Forests and have initiated a longleaf pine restoration project under the guidance of Bill Apperson. I'm hoping to implement a cost-share project for pre-commercial thinning later this winter. In addition, we have been fortunate to find very talented part-time personnel who have used remote sensing and GIS technology to characterize Virginia's pine resources. Following great success in determining the location and extent of pine stands in Virginia's "pine basket" counties we hope to use change detection technology to capture thinning, final harvests and ingrowth over time. Eventually, especially when all counties have digitized tax maps, we should be able to use aerial survey coordinates of beetle infestations to send notifications and advice directly to affected landowners.

Gypsy Moth - This year was hard on the gypsy moth, which is good. Hatch was poor in some places and slow almost everywhere. Cool, wet weather and a late freeze kept many hatchlings from getting a good start and fungus disease spread rapidly among developing caterpillars. A large percentage of larvae failed to reach the final stage. Despite this, populations were dense enough in some regions to cause nearly 80,000 acres of defoliation that could be mapped from the air, 70% of which occurred in Alleghany, Bath and Highland Counties. A map and acreage figures are on our Web site.

Mapping was particularly difficult because there was so little suitable weather for flying, and a sketchmapper was not always available. In addition, most defoliation was incomplete because larvae died before consuming all the foliage. The effects of other defoliators, oak anthracnose, hail and freeze injury all contributed to confusion over what had been caused by the gypsy moth.

It appears that the potential for noticeable defoliation next year is low. John Wright reported a pocket of moderate egg mass density in Bath County and scattered masses have been noticed in Greene, but no high-density population has been confirmed so far.

Slow-The-Spread applications next spring to disrupt mating in low-density populations will include 16 blocks covering 118,401 acres in Bland, Carroll, Floyd, Franklin, Giles, Montgomery, Patrick, Pittsylvania, Pulaski, and Wythe Counties.

Fall Cankerworm - Herb Reynolds was the first to report fall cankerworm defoliation this spring. A resulting aerial survey documented 8,397 acres of defoliation in fairly small patches scattered over many counties from Loudoun to Giles. Some of these were carry-overs from last year and some were new.

Other Defoliators -

• Eastern tent caterpillars produced a lot of webs across the Commonwealth this spring, but most failed to expand - presumably because of adverse weather and larval disease.
• Sawflies on loblolly pine drew attention in Dinwiddie and to a lesser extent in Accomack and Chesterfield. The introduced pine sawfly caused local defoliation of white pine in several counties, even including Orange; but generally, populations were much lower than in the past two years.
• Bagworms did very well in several widely dispersed counties and damaged quite a few ornamentals. The fall webworm was widespread, but not particularly heavy in any one area.
• Locust leafminers were very slow in getting started, but made up for it later in the summer.
• Sycamore lacebugs were noticeable, but scattered, as they have been for the last few years.
• Yellow-poplar weevil was generally light in southwestern Virginia, but moderate to heavy on some trees.
• Fairly unusual were reports of variable oakleaf caterpillar in Spotsylvania and Orange Counties - one from a landowner and another from John Giannico, Forester for Quantico.
• Walnut caterpillars on hickory resulted in several calls to Rich Reuse in Chesterfield. I noticed the related yellowneck caterpillar on our American chestnut trees on the Lesesne State Forest along with some unusually large spiny oakworms. Also unusual were reports of noticeable walkingstick activity in several mountain counties.
• Anthracnose defoliation of sycamores, probably along with some local freeze damage, was the last straw for many trees that have been suffering from combinations of prolonged drought, repeated anthracnose and lacebugs for several years. Mortality is scattered, but unusually common.
• Oak anthracnose was highly variable, even among trees in the same location, but it was prevalent enough in some spots to be noticed from the air. This was a banner year for leaf-infecting fungi of many kinds. Red maple was affected to an unusual degree. Walnut anthracnose resulted in early leaf shed as usual.
• Periodical cicada caused local branch flagging west of the Blue Ridge from Staunton south to the Tennessee line.

Invaders - The march continues. More and more organisms that don't belong here are imposing themselves on us, often at the expense of indigenous species. This trend is likely to continue and its potential long-term effects are truly disconcerting. Nonnative Invasive Plants of Southern Forests, a slick new publication from the Forest Service Southern Research Station was recently distributed to the Regional Offices. It's an excellent guide for identification and control of invasive plants and can be found at http://www.invasive.org/weeds/ along with additional information. It reminded me just how horribly well Microstegium vimineum (Nepalese Browntop or Japanese Stilt Grass) has been doing this year in taking over moist openings along streams, woods roads and trails. The only consolation is that in some places it seems to out-compete another noxious invader, Garlic Mustard. The Emerald Ash Borer has found its way to Ohio and our neighbor, Maryland. It could be in Virginia soon if it isn't already. West Nile Virus has infected Virginians in 9 counties and 2 cities. John Scrivani looked at the latest FIA data and noted that Ailanthus now falls among the top 50 Virginia species in terms of above-ground biomass. Better news is that a southeastern survey, in which DOF cooperated, failed to find evidence of Sudden Oak Death, and California researchers have recently discovered that the systemic fungicide Agri-Fos can help prevent this disease.

Elsewhere, two significant infestations of the Asian Longhorn Beetle have been discovered in Canada and at yet another place in New York. An exotic leafroller has become established from Massachusetts to New Jersey.

Shorts - Next year, VDACS will resume its highly successful pesticide disposal program and begin with the southeastern counties and Eastern Shore.

• Two recent studies reconfirm that 2,4-D does not pose a cancer risk.
• A new formulation of the insecticide Bifenthrin, trade name "Onyx," is registered and reportedly effective against bark beetles and borers on ornamental trees, but is for use only by commercial applicators.
• A study in Florida showed that trained dogs were highly successful in detecting termites of several species.
• Equitant means overlapping, as the leaves of some plants.
• Praying mantids gain fitness from pollen feeding.
• The Agricultural Research Service has come up with a promising new insect repellent that could be commercialized before long.
• Recent research indicated that southern pine beetles attack and kill Virginia pine more readily than loblolly, but do not reproduce as successfully in Virginia pine.
• Potamic means relating to rivers, and brumal means occurring in or related to winter.
• Progress is still being made in the development of American elms resistant to Dutch elm disease.
• A newly patented virus could help to control disease-carrying mosquitoes.
• Methoxychlor may no longer be used on food crops; if you see it in the pest management guides, don't recommend it.
• A chemical produced by knapweed holds promise as a new and relatively benign herbicide.
• More than 30 million plastic water bottles end up in the trash every day.

Fast Talkin Boy - Another gem from Virginia Folk Legends: From Charlotte Collins, interviewed by Emory Hamilton, Wise County, 11/19/40 - "I've heard my grandmother tell this many a time. She said one time a lot of people was coming from church and a boy and girl in the bunch who was sweethearts had walked on before, you know, just like sweethearts will. They got on ahead of the crowd a ways and sit down. He noticed that she was getting pale as death. He watched her a few minutes and saw that something had to be done. He unlooseded her clothes and found that a black snake had wropped her body. He couldn't pull it loose and finally he took his knife and cut it loose. She got alright in a few minutes after the boy cut the snake loose."

Falcata Fix - According to Native American Ethnobotany, the Cherokee used southern red oak to treat dysentery, mouth sores, "lost voice," chapped skin, asthma, chills and fevers. A little hard to understand is that bark was used both as an emetic and for indigestion - that is until you realize that it can be used for "any debility of the system." Plant one today.

HEALTH

HEALTH PRIMER

Climate Change

Climate change is nothing new. Global temperature and precipitation have fluctuated greatly over the course of Earth's history. The causes remain a subject of investigation and debate. Both the character and the consequences of future climate change are still a matter of speculation. There is broad agreement that average global surface temperature has increased over the past century and that greenhouse gases in the atmosphere have also increased, largely as a result of fossil fuel combustion. There is much less agreement about the connections between greenhouse gases and past or future climate change. The complexities are daunting. This subject is important because seemingly small changes in global climate could have dire consequences. Average surface temperature during the last ice age was only about 5o C cooler than today. Any attempt to counteract climate change would be hugely expensive and controversial, so it would help to know what we were doing. Yet projections and predictions vary widely. Possibilities range from rapid warming to rapid cooling and from wetter to drier over the next century.

Our understanding of what climates were like in the distant past comes mainly from studies of ice cores and deep ocean sediments. Certain elements commonly occur in more than one form (isotope) and the relative amounts of these forms are influenced by temperature. Records of temperature fluctuations over long periods of time are thus reflected in the isotopic composition of ancient marine sediments (e.g., animal shells) as well as in the water and air trapped in glacial ice. The ages of cold and warm periods are determined by various means, including the decay rates of unstable isotopes. There have been many shifts from cold to warm climates over the past few million years.

One source of climatic variation relates to changes in the relative positions of Earth and Sun. This is more than the familiar 23.5o tilt of Earth's axis (obliquity) and our annual revolution around the sun, which regulate the seasons. Gravitational interactions among the planets cause obliquity to range from 22^o to 25^o and back again every 41,000 years while at the same time the axis moves in a small circle every 26,000 years. Additionally, Earth's orbital position creeps through its elliptical path around the sun (precession) so that each January, for instance, it is not exactly in the same place it was the previous January. It returns to the same spot about every 22,000 years. There is even long-term variation in the ellipticity of Earth's orbit. All these motions cause gradual changes in the amount of solar radiation (insolation) reaching any given part of the globe at a particular time of year. This helps explain many glacial and interglacial periods of the past. When summertime insolation increases at high latitudes, for example, a reduction in the continental ice sheet and a corresponding increase in sea level might be expected, but it's not that simple. There are other factors that interact with these astronomical influences and modify their effects. One is the varying amount of radiation reflected by our planet (albedo), particularly the polar ice caps as they grow and shrink. Another is cloud cover. Clouds both reflect incoming radiation, which has a cooling effect and trap heat radiating from the earth, which has a warming effect. Winds exert a powerful influence on atmospheric and ocean dynamics. They shift ocean currents and transport heat and moisture. The atmosphere also contains tiny particles, called aerosols (e.g. ash, pollen, spores, bacteria, salt), that tend to reflect heat. Then there are the influences of ocean temperature, salinity and density. The oceans store and transport vast amounts of heat, and ocean currents probably play a major role in climate change.

Today, salinity of the North Atlantic is higher than that of the North Pacific. Ocean water density increases with increasing salinity and decreasing temperature. In winter, as surface water cools in the North Atlantic, it becomes dense enough to sink. This downwelling is part of a complex global flow in which deep, cold water flows south from the North Atlantic, circles Antarctica, enters the Indian and Pacific Oceans where upwelling occurs and warm, surface waters flow back to the North Atlantic. Obviously, this flow affects air and water temperatures and associated organisms around the world - just as warm water from the Gulf Stream moderates conditions in northern Europe. An increase in global temperature could upset the salinity, temperature and density relationships that drive this flow with unpredictable and potentially dramatic results.

There is clearly a strong belief among many scientists and non-scientists that fossil fuel consumption and greenhouse gas production are more likely than not to increase global warming. What would result from continued warming is unknown. This is not a strong basis for developing informed, science-based policy. Political action related to global climate change is more likely to stem from belief than from knowledge.

Solitary Wasps

Familiarity with the social wasps is often renewed each fall when encounters with yellowjackets and hornets tend to increase. Solitary wasps, on the other hand, are largely ignored despite their far greater number and diversity (25,000 species or more). The grouping of these insects is somewhat arbitrary - many wasps that live solitary lives are not included. Most of the included species are predators of other insects or spiders. Adult females forage alone and usually abandon their nests, if they have one, while their offspring are still in the egg stage. As with other Hymenoptera, males develop from unfertilized eggs and females develop from fertilized eggs. In this way, mothers can control the gender of their offspring.

Last modified: Tuesday, 12-Aug-2008 16:45:13 EDT