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FOREST CONSERVATION NEWS TODAY
Climate Change Number One Threat to Forests
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Forest Networking a Project of Forests.org, Inc.
http://forests.org/ -- Forest Conservation Portal
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http://www.ClimateArk.org/ -- Climate Change Portal
August 8, 2002
OVERVIEW & COMMENTARY by Forests.org
Climate change is the number one threat to forests. The
preponderance of scientific evidence strongly indicates that forests
are not a climate change panacea. Several recent studies indicate
that forests will not appreciably act as carbon sinks as climate
change progresses, that indeed they may be the source of additional
carbon, and that tree planting will not mitigate the need to
drastically reduce greenhouse gas emissions. One new study reported
on below shows that as temperatures rise rainforests may be a net
source of carbon dioxide (CO2) to the atmosphere, and another
indicates that scientists have overestimated the potential of trees
and shrubs to soak up carbon dioxide from the atmosphere. Tropical
forests throughout the world appear to be changing significantly in
structure, dynamics, and composition; perhaps as a result of changes
in the world's atmosphere through the burning of fossil fuels,
agriculture, and other activities.
However much this science may distress those invested in carbon
sinks, the evidence is mounting. Just look around you – the World’s
forests are burning. Clearly climate impacts forests more than
forests impact climate. Human-induced climate change, well
documented at http://www.climateark.org/, threatens the ecological
fabric of being. This being the case, there can be no meaningful
forest conservation without aggressive and immediate policy to reduce
greenhouse gas emissions.
Large, intact, contiguous forests are most likely to adapt to rapidly
changing climate. Strictly protecting such primary forests is far
more advantageous in terms of carbon storage (to say nothing of other
environmental services) than industrial plantation forestry. Such
forests are large enough to effect their own micro-climate, have more
potential for evolutionary adaptation, and are less likely to burn
unnaturally.
So plant trees and protect forests, but do not use this to justify
over-consumption and rampant air pollution. Only swift and major
reductions in the carbon intensity of the World’s economies can save
us now. Massive investments in renewable energy are the best bet for
the survival of both forests and humans.
The interesting thing about environmental sustainability is that when
you start pulling on one strand of the web, you see it is all
connected. The well-being of forests, climate, water, oceans and
humanity all depend upon each other. This is the basis for the new
Environmental Sustainability portal at
http://www.EnvironmentalSustainability.info/ . Join the movement for
ecological sustainability and justice – get active, organize and make
a difference.
A small donation at http://forests.org/donate/ would be helpful as
well. The Earth needs you.
g.b.
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ITEM #1
Title: The Effects Of Human-Caused Atmospheric Changes On Tropical
Forests
Source: ScienceDaily Magazine & Smithsonian Institution
(http://www.si.edu/)
Date: August 7, 2002
City, Panama - For more than a century humans have been changing the
composition of the world's atmosphere through the burning of fossil
fuels, agriculture, and other activities. The resulting climate
changes may already be having far-reaching impacts on tropical
forests. A symposium at the 2002 meetings of the Association for
Tropical Biology, hosted by the Smithsonian Tropical Research
Institute (STRI), Panama, examined the evidence for these changes and
their implications for the future. Organized by Yadvinder Mahli of
the University of Edinburgh and Oliver Philips of the University of
Leeds, the symposium included 12 presentations and four general
discussion sessions. A selection of some of the results follows.
Yadvinder Mahli provided an overview of ongoing climate changes as a
result of increasing carbon dioxide and other greenhouse gases in the
atmosphere. Since the mid-1970s all tropical forest regions have
warmed, although with regional variation in intensity. There has been
even more regional variation in precipitation, but there appears to
have been an overall global decline. However, no global trend in dry
season intensity has been detected.
Data analysis and models have suggested that increased temperature
and atmospheric CO2 will increase the amount of carbon stored by
tropical forests by stimulating tree growth. Deborah Clark of the La
Selva Biological Station, Costa Rica, re-evaluated the evidence to
suggest that tropical forests may not be carbon sinks after all, but
instead end up contributing even more carbon dioxide to the
atmosphere as temperature rises. Data from La Selva show a strong
negative correlation between tree growth and higher temperatures.
Temperatures experienced by canopy leaves may be close to the point
at which respiration exceeds photosynthesis so that net production of
CO2 results. Positive feedback between higher temperatures and CO2
production by tropical forests could be catastrophic by resulting in
accelerated increase in global CO2 levels.
Tropical forests throughout the world appear to be changing
significantly in structure, dynamics, and composition. Oliver Philips
presented analyses (with collaborators T. Baker, S. Lewis, Y. Malhi,
N. Higuchi, T. Killeen, W. Laurance, D. Neill, N. Silva, R. Vasquez,
and B. Vincenti) of data from permanent plots in mature forests
throughout the tropics. Tree turnover (the difference between
mortality and the recruitment of new individuals into the population
through growth) has doubled throughout the tropics in recent decades,
from 1% annually in the 1950s to 2% in the 1990s. Basal area (the
total area of the plot occupied by tree stems) has increased in
Amazonia, but not in the rest of the tropics, and large lianas have
increased in western Amazonia. Such widespread changes over such
large areas suggest that a common mechanism is at work.
How resistant are tropical forests to declining precipitation? Daniel
Nepsted (with collaborators P. Motinho, M. Dias-Filhod Ray, D. Ray,
L. Solorzano, G. Gardinot, and I. Tohver) experimentally reduced the
rainfall reaching the ground in forest plots in
growth of smaller trees declined within a few weeks, and their
mortality increased three-fold over two years. However, litter fall
increased only after two years of treatment. This forest apparently
avoided drought-induced leaf-shedding and adult tree mortality for
two years by tapping soil moisture to a depth of 20 meters.
Note: This story has been adapted from a news release issued by
Smithsonian Institution for journalists and other members of the
public. If you wish to quote from any part of this story, please
credit Smithsonian Institution as the original source.
ITEM #2
Title: Global Warming is Changing Tropical Forests
Source: Environment News Service, http://ens-news.com/
Date:
changing the global climate, and these changes are having far
reaching effects on tropical forests, according to scientists from
around the world gathered here last week for the Association for
Tropical Biology annual meeting.
The scientists were hosted in
Research Institute. They explored the Smithsonian's tropical biology
research station at Barro
became an island when central
construction of the
The Association for Tropical Biology says that tropical forests are
undergoing unprecedented changes as 1.2 percent of the remaining
forest is removed each year, as atmospheric carbon dioxide which
fuels plant growth increases by 0.4 percent each year, and as global
climate change begins in earnest.
Yadvinder Mahli from the
Ecology and Resource Management provided an overview of ongoing
climate changes as a result of increasing carbon dioxide and other
greenhouse gases in the atmosphere.
Since the mid-1970s all tropical forest regions have warmed, Mahli
said, although with regional variation in intensity.
There has been even more regional variation in precipitation, but
there appears to have been an overall global decline. No global trend
in dry season intensity has been detected.
Higher global temperatures and increases in atmospheric carbon
dioxide, the major greenhouse gas, will increase the amount of carbon
stored by tropical forests by stimulating tree growth, data analysis
and models have suggested.
Selva Biological Station in
told the symposium that tropical forests may not be carbon sinks that
can be used to absorb carbon dioxide generated by the burning of
fossil fuels.
Instead, tropical forest may end up contributing even more carbon
dioxide (CO2) to the atmosphere as temperature rises, she said.
Data from La Selva show a strong negative correlation between tree
growth and higher temperatures. Temperatures experienced by canopy
leaves may be close to the point at which respiration exceeds
photosynthesis so that net production of carbon dioxide results,
Clark suggests.
Positive feedback between higher temperatures and CO2 production by
tropical forests could be catastrophic by resulting in accelerated
increase in global CO2 levels, she said.
Dr. Oliver Philips of the University of Leeds School of Geography
presented analyses, conducted with Malhi and others, of data from
permanent plots in mature forests throughout the tropics.
Tree turnover, the difference between mortality and the recruitment
of new individuals into the population through growth, has doubled
throughout the tropics in recent decades, he said, from one percent
annually in the 1950s to two percent in the 1990s.
The total area of the plot occupied by tree stems has increased in
Amazonia, but not in the rest of the tropics, and large lianas have
increased in western Amazonia. Such widespread changes over such
large areas suggest that a common mechanism is at work, said Dr.
Philips.
ITEM #3
Title: Study: In global warming fight, trees not always best answer
Source: Associated Press
Date: August 7, 2002
LOS ANGELES (AP) -- Scientists have overestimated the potential of
trees and shrubs to soak up carbon dioxide from the atmosphere,
according to a new study.
The reassessment casts doubt on whether planting trees is always a
positive step in the fight against global warming, as President Bush
and others have suggested.
In the study, published in Thursday's issue of the journal Nature,
Duke University scientists say trees and shrubs growing in areas of
abundant rainfall are less effective storehouses for carbon than
native grasslands they have steadily replaced across much of the
western United States.
Vegetation stores carbon that otherwise might trap heat in the
atmosphere, driving up temperatures and leading to climate change.
Previous studies have ignored what was going on below ground, said
Robert Jackson lead author of the study and an associate professor of
biology at Duke University.
In wet locations, replacing grass with shrubs and trees actually can
lead to a decrease in the amount of carbon locked up in organic
matter mixed in the soil, Jackson said. The amount can be enough to
offset any gains achieved above ground.
"The study suggests that we need to look very closely at what's below
ground before we add up just what's stored above ground in tree
trunks," Jackson said.
Scientists studied six pairs of adjacent western grasslands. In one
of each pair, trees and shrubs had cropped up sometime in the last
100 years.
In the drier sites, the invasive growth led to an increase in the
amount of carbon locked up in the soil. In wetter areas, however, the
opposite was the case, Jackson said. It is not clear what caused the
change.
"Grasses are deceptively productive," Jackson said. "You don't see
where all the carbon goes so there is a misconception that woody
species store more carbon. That's just not always the case."
Previously, studies estimated that U.S. shrublands contain about 440
million tons of carbon. The number may be closer to 280 million tons,
Jackson said.
That result suggests shrublands, by absorbing carbon from the
atmosphere, do less to balance emissions from the burning of fossil
fuels than previously thought, Jackson said.
"It would not surprise me at all if they were absolutely spot-on
right," said Steve Pacala, a Princeton University professor ecology,
who wasn't involved in the study. However, he said he didn't consider
the study definitive, given uncertainties in its measurements of the
carbon contained in woody roots.
The study helps dispel the notion that humans can plant their way out
of global warming, said Daniel Becker, director of the Sierra Club
global warming and energy program.
"We are going to need to tackle the industrial sources of emissions
head-on rather than just plant a bunch of trees," Becker said.
As part of his administration's strategy for curtailing carbon
dioxide emissions, Bush has proposed tax incentives for farmers who
plant trees.
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