Global Warming Effects on Trees

An article in the Fall 1995 Earth Island Journal by Charles E. Little claims that "America's Trees Are Dying". Here is the introduction for that article.
 

"After 30 years as an environmental-policy analyst, journalist and author Charles Little spent three years traveling across the US, visiting forests and woodlands in 13 states. In the process, he interviewed the country's top forest scientists, met with government and university researchers, and reviewed hundreds of scientific papers and reports. His discoveries are profoundly disturbing. The following excerpts have been adapted for the Journal from Little's new book, The Dying of the Trees: The Pandemic in America's Forests.

From The Dying of the Trees: The Pandemic in America's Forests, by Charles E. Little. Copyright (c) Charles E. Little, 1995. Reprinted by arrangement with Viking, a division of Penguin Books USA Inc. To order the book, please call 1-800-253-6476.

The trees are dying. Not only in the rainforests of Brazil and Southeast Asia, where they are felled by the chainsaws of international greed, local poverty and ecological ignorance, but also in Europe and right here in the US.

From the cedars of Alaska to the palms of Florida, from the maples of Canada and New England to the pines and incense cedars of the Sierra Nevada, the incidents of death and decline are increasing at an alarming rate.

Some argue that the progression of tree death and forest decline in this century, and especially since World War II, is either coincidence or simply a matter of selective reporting. Everything is all right; it is just the natural ebb and flow of nature. But that is not what I have learned from the scores of scientific scholars I have interviewed, and the mountain of papers I have studied. They say something else. What these distinguished sources are describing is a pandemic -- an epidemic that is everywhere.

In the US, the trees are dying on the ridges of the Appalachian mountain chain and in the sugar bush of Vermont. They are dying in the mid-South border states, in the thick forests of central Michigan, on the mountainsides of Colorado and California, along the Gulf of Mexico, in the deserts of the Southwest and they are dying in the Northwest -- even before they are cut."

"The more trees that die, the more trees that will die. In the forlorn formulation of ecologist George Woodwell, climate warming from an increasing greenhouse effect could, in temperate forests especially, increase the respiration rate of trees to the degree that it may surpass the rate of photosynthesis. The tree would then no longer be a net producer of oxygen, but a net producer of carbon dioxide.

'The amount of carbon dioxide that could be injected into the atmosphere,' wrote Woodwell and longtime associate Richard Houghton in Scientific American, could theoretically approach "approximately 750 billion metric tons, or about the same amount of carbon as there is in the atmosphere currently." Implied by this analysis is a devastating feedback loop in which trees in the vast northern hemisphere forests, instead of absorbing carbon, add to the global build-up of CO2 in a nightmarish cycle, whose finale could be a worldwide policy decision to cut down trees in order to protect the Earth's oxygen supply!"

"Environmentalism practices the language of crisis: to insist that something be done before it is too late. But what we need now is a language (and the intellectual constructs that go with it) to deal with a post-crisis environmental condition. And our response to the dying of the trees is at the heart of the matter.

In the course of my research, I have learned things I wish I had not learned. I have learned that the trees are dying. And that the more trees die, the more will die. I have learned that we have crossed the threshold. And I simply do not know how we can get back safely to the other side.

Such a conclusion can lead to despair. I think the only antidote to despair is to stay firm in the belief that, as William Wordsworth put it in Tintern Abbey, "nature never did betray the heart that loved her."

We must begin to love her as we have never been asked to love before. Even then, it will take a century or more for environmental repair: for letting nature heal herself.

Thus have we come to the crux of the matter: the trees could save us if we would save the trees."

An article by Mark E. Harmon, William K. Ferrell, Jerry F. Franklin in SCIENCE, (VOL. 247, 9 FEBRUARY 1990, pp. 699-701) notes the "Effects on Carbon Storage of Conversion of Old-Growth Forests to Young Forests"

The authors claim that:
 

"Conversion of old-growth forests in the Pacific Northwest has been a significant source of C in the atmosphere....In reality, the total flux from this region from changes in land use will have been considerably higher because of the harvest of second-growth forest, widespread fires, and the removal of forest land from production by such processes as road construction and urbanization. Given the small area we are considering, a mere 0.017% of the earth's land surface, old-growth forest conversion appears to account for a noteworthy 2% of the total C released because of land use changes in the last 100 years.

Although reintroducing forests to deforested regions will increase C storage in the biota, conversion of old-growth forests to younger forests under current harvesting and use conditions has added and will continue to add C to the atmosphere. This conclusion is likely to hold in most forests in which the age of harvest is less than the age required to reach the old-growth stage of succession. The amount of C added by conversion will vary among forests, depending on their maximum storage capacity and the difference between the timber rotation age and the age of the old-growth state within the given ecosystem. "

Another recent publication by Greenpeace International called "The Carbon Bomb: Climate Change and the Fate of the Northern Boreal Forests" further emphasizes the global nature of the effects of the loss of forest diversity. This report was researched and written by Kevin Jardine and edited by Lyn Goldsworthy, Abbie Thomas and Michael Szarbo for Greenpeace International. What follows is from the Executive Summary of this publication.
 

"THE NORTHERN BOREAL FORESTS make up almost a third of the Earth's forests, covering about 15 million square kilometres, and ranging across Russia, Canada, the United States, Scandinavia, and parts of the Korean Peninsula, China, Mongolia and Japan.

Drawing on the latest research on forest ecology, the impacts of recent climate change, and studies on projected future climate change, this report shows that between 50 and 90 percent of the existing boreal forests are likely to disappear as a result of a doubling of atmospheric levels of carbon dioxide and other greenhouse gases. This doubling is expected to take place over the next 30-50 years, and is likely to create abrupt changes in the Earth's climate that would result in severe forest decline. The rate of decline is still uncertain, but is likely to be rapid in many regions, and driven by massive fires, insect outbreaks and storms.

There is growing and alarming evidence that this decline is already beginning and is driven by a level of greenhouse gases in the Earth's atmosphere that is currently higher than has been seen in over 150,000 years.

The projected decline could contribute to the rapid release of hundreds of billions of tonnes of additional carbon dioxide into the atmosphere, accelerating the rate of climate change.

The emerging and potential impacts of climate change threaten the more than one million indigenous people who live in the boreal forest, as well as a loss of wildlife and plant diversity through the destruction of habitat. Key endangered species living in the boreal forest, such as the Siberian tiger, are already on the brink of extinction. Climate change and current logging practices further threaten such species.

Current logging practices are aggravating forest decline by decreasing the ability of the boreal forest to withstand disturbances, increasing stress by changing moisture and temperature regimes, and releasing greenhouse gases.

Serious disturbance of the boreal forest ecosystem can be traced back to an abrupt shift in the global climate in 1976. Since then higher temperatures have sparked larger and more frequent fires throughout the boreal forest, and the number of storms and damaging insect outbreaks has increased. These disturbances have been accompanied by a decline in conifer populations in the southern part of the boreal forest.

Unless atmospheric concentrations of greenhouse gases are quickly stabilized climate-vegetation models predict that large areas of boreal forest will be reduced to patchy open woodland and grassland, resulting in lowered biological diversity and a reduced ability to store carbon.

Studies of the global carbon cycle suggest that boreal forests are not absorbing as much carbon as they did before 1976. As a result, the atmosphere already appears to contain 10-15 billion tonnes of carbon more than it would have if forests had continued to absorb carbon at the pre-1976 rate.

If boreal forests continue to decline, estimates suggest that burning and rotting of boreal forests could contribute to the release of up to 225 billion tonnes of extra carbon into the atmosphere, increasing current levels by a third. This would accelerate the rate of climate change.

While it is possible that the boreal forest could expand into the frozen tundra as temperatures increase, such an expansion would likely be delayed by slow tree migration rates and the adverse effects of increased ultraviolet radiation on trees from ozone depletion.

Even in the long term, the boreal forest is not expected to expand enough to compensate for the deterioration in the southern part of the forest.

This report calls on policy and decision makers to radically rethink and change energy policies and logging practices in boreal forest countries in order to protect and preserve the climate and biodiversity. Such changes are consistent with their obligations under the Climate Convention and Biodiversity Treaty established by the 1992 UN Earth Summit in Rio de Janeiro, Brazil.

GREENPEACE BELIEVES that climate change and severe forest decline can only be halted by:

* A planned and orderly global phase-out of fossil fuels and their replacement by the efficient use of renewable and clean energy sources, including the immediate reduction of greenhouse gas levels by at least 20 percent by 2005.

* An end to global deforestation and the introduction of a programme of ecologically-based reforestation.

* The immediate phase-out of CFCs, HCFCs and HFCs, and their replacement by chemicals which do not damage the ozone layer or contribute to the human-induced greenhouse effect. "

If I were to try to design a forest management system to destroy productivity it would be difficult to think of a worse system than this.