Monday, February 13, 1989

Disaster In The Branches

Woodstock Consultant Takes The Pulse of the Forest


During a walk through his own woodlot, the forester points out numerous young saplings and older trees . . . on which the apical bud (uppermost growing tip) is dying back each year, forcing side branches to take over as the dominant growing point and creating crooked, deformed branching patterns instead of the normally straight stems seen on healthy trees.



Special to the Valley News

copyright 1989 by Michael J. Caduto
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When you see an unhealthy tree, is it one more symptom of a general and rapid forest decline, or merely a tree dying in the natural course of events?

Expert opinions on the state of forests here in the Northeast range from bleak to reassuring, with the full spectrum of views in between.

Gerry Hawkes is an independent forestry consultant based in Woodstock and a member of the recently appointed Governor's Task Force on Forest Health.

Hawkes' interest in forestry began at an early age. Members of his mother's family have made their living from farming in the area since the 1790s. "When I was young I learned a lot about the land and its history from my grandfather, father and uncles."

After earning a B.S. degree in forestry from the University of Maine in 1971, Hawkes worked as a Peace Corps volunteer in the sub-Saharan country of Niger where in two years he gained an intimate insight into the human suffering brought on by drought and environmental abuse.

Over the years since his Peace Corps service, Hawkes has left his forestry practice in Woodstock for short-term consulting assignments in Bourkina Faso (formerly Upper Volta), Morocco, the Philippines and Nepal, under the auspices of U.S. Agency for International Development, the World Bank and the United Nations.

A large part of Hawkes' forestry consulting in the Woodstock area involves the preparation of detailed maps and land management plans for private woodland owners.

In the course of assessing the forest resource and preparing plans he became so concerned with what he felt to be the steadily declining health of the forests that he developed a system for gathering tree health data and then wrote several computer programs to analyze that data.

To date he has analyzed data from nearly 900 sample plots on properties within a 35-mile radius of Woodstock. The picture is mixed.

"I have properties that are in bad shape and others that show few unusual signs of decline and death," says Hawkes. "On some properties up to 35 percent of the tree volume (basal area) was either dead or obviously dying in 1987 with an additional 20 to 30 percent in marginal health."

It appears that the forest death generally lessens approaching the Connecticut River and increases toward the Green Mountains. The problem seems to be increasing rapidly and affecting lower and lower elevations.

This decline and death, notes Hawkes, "is affecting a number of tree species locally, such as butternut, sugar maple, basswood, red spruce, poplar, ash, red oak, Norway spruce, beech and white birch. "Most of the trees are suffering from a lack of vigor and an increased susceptibility to the diseases and insects that ordinarily infect them."

Hawkes attributes the recent (1988) outbreak of pear thrips on sugar maples to the fact that the trees were already weak from years of declining health and could not resist the attacks of an insect that had previously been thought to present no threat whatsoever (as evidence by its scientific name: Taeniothrips inconsequens).

The areas that were hardest hit in Vermont by pear thrips defoliation this past summer lay in Orange County and the four southern counties of Windsor, Windham, Rutland and Bennington. Well over one-half million acres of forest were damaged.

During a walk through his own woodlot, Hawkes points out numerous young saplings and older trees of birch, maple, ash, and others on which the apical bud (uppermost growing tip) is dying back each year, forcing side branches to take over as the dominant growing point and creating crooked, deformed branching patterns instead of the normally straight stems seen on healthy trees.

In General," he says, "tree vigor has been lower in recent years, foliage smaller and thinner, and autumn coloration of leaves occurring one to two weeks earlier that normal.

"Early coloration on individual trees and limbs has always been a sign of poor health and often impending death. Now the entire forest appears to be coloring early."

"The only logical, underlying explanation I can come up with for such widespread forest health problems, especially since similar declines and mortality problems, occurring in Europe and other parts of the northern hemisphere, is atmospheric pollution," he says.

"Multiple air pollutants are the most logical cause," he adds. "Acid rain is only a part of it. The conclusion in Europe is that there is no one pollutant. You get varying mixes and concentrations of pollution in different areas, plus varying soil conditions, amounts of rainfall, etc. Somewhere around 3,000 toxic chemicals are routinely emitted into the atmosphere.

"This past summer we had low visibility due to ozone and sulfur dioxide - the precursor of the sulfuric acid in acid rain,"

Twice during these past summer months in Vermont and New Hampshire, he says, the amount of ozone in the air exceeded the maximum level (120 parts per billion) established by the federal government.

In fact, he points out, the ozone levels in the Upper Valley (30-50 parts per billion) are higher than the levels used by some researchers in tests that showed a substantial decline in the growth, vigor and photosynthetic activity of red spruce. Hawkes' international experience causes him to see New England's forests from a broad perspective. "While I worked in West Africa during the famine of 1971-1973, he says, "the environmental destruction was incredible. I could see parallels to what impact human developments were having there and what would be happening here. When I returned to Woodstock in 1973 I saw the early stages of forest decline occurring here.


"A lot of people are not willing to project a future for which there is no historical precedent," he says. "In the past there have been ups and downs in tree health, but this forest decline is different."

Gerry Hawkes

Forestry Consultant



"I believe pollution is stressing the ecosystem through direct and indirect chemical effects as well as global climatic changes, reducing the health and vigor of trees, and making them more susceptible to attacks of insects and disease.

"I see the problem as being extremely serious with major ecological disaster manifesting itself here in only a few years."

Not everyone agrees with Hawkes' pessimistic view of the present and future condition of our forests in Northern New England. Several forestry officials take a more cautious approach.

"You can see dead and dying trees in the woods," observes Brent Teillon, chief of forest protection for the Vermont Department of Forest, Parks and Recreation in Waterbury, "but I don't believe we're going to lose half of our trees in the next four to five years.

Brian Stone, Vermont's chief of forest management, concurs: "We don't have the scientific evidence to support that allegation. Trees are living things that have their ups and downs. In the summer of 1988 the trees were in a down period. Thrips populations are up and damage will continue next year."

During the period from 1975-1977 the sugar maples were also in a decline due to drought and insect damage, according to Teillon, but the health of the trees rebounded. These natural stresses, along with air pollution, can cause to weaken and die.

However, Teillon does not dismiss the possibility that air pollution may play a role. "The assertion that there's an underlying stress due to air pollution - that's a hard one to assess, though we'd like to see more air pollution control in the U.S."

Barbara Burns, a state forester who works out of Springfield is also circumspect. "Trees are bathed in air pollution and so are the insects. It is plausible that there's a relationship between air pollution and the current thrips damage."

The evidence, however, is far from clear, she says. She points to a comparative survey done in 1997 and again in 1985, during which the health of 54 sugarbushes was measured around Vermont. Over this eight-year period there was no decline; the overall health of the trees remained stable.

But she also points out that the trees may not have been in the best health to begin with in 1977, that eight years is a short time for tree health to change much, that surveys by their very nature tend to produce variable results and that sugarbushes are managed intensively and may not reflect the general conditions of unmanaged forests in Vermont.

Jon Bouton, forester for Windsor County, says that in some cases, the Forestry Department's surveys actually show a slight improvement in the general health of sugarbushes over the past five years. But, he says, "the cards aren't all in yet. The more we study, the more we'll find out.

Andy Friedland of the Environmental Studies Department of Dartmouth College does not accept Hawkes' reasoning at all. "There is no scientific consensus on the effects of air pollution on high elevation forests," he says. During his studies of red spruce in the Eastern mountain forests, Friedland concluded that this particular type of tree - a sensitive indicator species - is in decline, but that the forests as a whole are not.

Friedland's hypothesis is that exposure to ozone and acid rain is causing red spruce to be more susceptible to die-back from the natural stresses of cold, frost damage, and drying winds. Since the early 1960's the growth of red spruce has declined to a point lower than any year since 1890.

Why the difference among these views of forest health in the Northeast?

"We don't see the forest conditions very differently than Gerry Hawkes," says Brian Stone, but we see the glass as half full - the optimistic side of that. The dynamics of the forest are strong enough to deal with these stresses.

Hawkes' response is that past experience, on which these experts rely, may no longer be relevant. "A lot of people are not willing to project a future for which there is no historical precedent," he says. "In the past there have been ups and downs in tree health, but this forest decline is different.

"The environmental impacts of our rapidly multiplying and industrializing human population are unprecedented on a global scale, and are causing unprecedented damage to forests and other ecosystems which will only continue to worsen unless fundamental changes in human behavior are made soon."


NOTE:  Since 1989 the health of  forests in the Northeastern United States has not declined as rapidly as I had predicted. I believe this is due, in large part, to clean air regulations, the reduction of acid precipitation, and relatively good climatic contidions for tree growth.  However the damaging effects of air polluttion and acid precipitation continue.  Soon calcium depletion from soils may reach a critical threshold leading to rapid die-off of large areas of forests.  We bought ourselves some time, but we are far from assuring a healthy future for our forests.   ~  Gerry Hawkes  ~  February 2005




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