Deforestation Decreases Rainfall
The
protected lush cloud forests of Costa Rica are drying and shrinking
because
of deforestation on coastal lands many miles away according to the
October
19, 2001 Science Magazine. “It¹s incredibly ominous that over such
a
distance deforestation can alter clouds in mountains.
This is a very
serious
concern”, said Gary S. Hartshorn, president of the Organization for
Tropical
Studies, a consortium of Rain Forest Researchers at Duke
University.
The latest findings indicate that as trees on Costa Rica's
coastal
plains are removed and replaced by farms, roads and settlements,
less
moisture evaporates from soil and plants, in turn reducing clouds
around
forested peaks 65 miles away.... the moisture content of the clouds
over the
mountains has declined by about half since intensive land clearing
began
in the 1950s.... Also, the
cleared land is warmer, pushing the
base
of clouds nearly a quarter of a mile higher on some days, meaning they
pass
over the mountain range dropping little moisture.
In contrast, clouds
were
more abundant over forested lowlands just across the border in
Nicaragua,
where forest still blankets much of the coastal plain, the study
says.”
(Deforestation Far Away Hurts Rain Forests, Study Says. Gary
Polakovic,
Los Angeles Times, 10/19/2001).
http://forests.org/archive/general/defforaw.htm
Half of China is now desert. This is due to a combination of too much
grazing,
plowing, deforestation, and general over-population.
“Deforestation
in southern and eastern China is reducing the moisture
transported
inland from the South China Sea, the East China Sea, and the
Yellow
Sea”, writes Wang Hongchang, a Fellow at the Chinese Academy of Social
Sciences....
“When tree cover is removed, the initial rainfall from the
inland
moving, moisture laden air simply runs off and returns to the sea.
As
this recycling of rainfall inland is weakened by deforestation, rainfall
in
the interior is declining.” (World Watch Institute Alert, 5/23/01).
Millions
have been migrating to escape the dried-up lands, and there have
been
such huge dust storms coming out of central China that the dust has
crossed
the Pacific to our west coast and was still visible from the ground
in
Salt Lake City.
In
the Brazilian Amazon, “a study near Manaus, Brazil showed that forests
return
three-fourths of rainfall to the atmosphere, leaving one-fourth as
runoff....
When land is deforested, however, the ratio is roughly
reversed,
with a quarter of the rainfall being
returned to the atmosphere
and
three-quarters running off quickly. Rainfall
in the region is
accordingly
reduced, as the atmosphere holds less returned moisture that can
become
rain later in the cycle.” (Brown, April
1985 Natural History).
In
El Salvador, “Old timers see the changes in the hills, once forested, now
covered
by nothing but rocks and sand. They
note the difference in the
river,
nearly dry in recent years. They feel it in the weather, hotter now,
less
rain”. (Houston Chronicle,
6/13/98).
"The
great bridging cloud that reached from the forest of Maui to the island
of
Kohoolawe, has disappeared as cutting and cattle destroyed the
upper
forests
on Maui." (Trees: Guardians of the Earth)
http://forests.org/ric/good_wood/trees_gs.htm#anchor308408
And
in Kenya, “Illegal deforestation partly to blame for devastating
Drought”.
See http://forests.org/articles/reader.asp?linkid=7542.
(From
Boston Globe, 2/10/02, by Declan Walsh, Globe Correspondent)
“At
the regional level, deforestation disrupts normal weather patterns,
creating
hotter and drier weather”....
From
“Deforestation: Tropical Forests in Decline” by: John Roper
Forest
Conservation Consultant, Burnaby, British Columbia, and
Ralph
W. Roberts R.P.F., Senior Advisor, Forestry and Conservation
Canadian
International Development Agency, Hull, Quebec, Canada
January,
1999. See:
http://www.rcfa-cfan.org/english/issues.12-6.html
The
U.N. recently put out an alert about mountains which they
refer to as
the
world¹s water towers because globally, half of our fresh water comes
from
mountains, yet the mountains everywhere are under assault by timber
interests,
mining, recreation, urban sprawl, and wars.
It¹s the forests on
mountains
that catch and hold water for us. But
wherever they are, forests
give
us water, and we¹ve been very careless with them.
How simple:
increase
our forest cover, but the resistance to restoration is huge, and is
steadily
decreasing mature forest cover. Three
hundred years ago old
growth
east coast pine trees were commonly up to 6 feet in diameter, now
they’re
three feet maximum. (From Alice Atwater¹s book, “Water”, a great
read).
Logging has been taking the biggest trees and leaving the smallest
for
centuries so “mature” forests are of smaller diameter trees and
therefore
produce less water vapor. We need
to increase total area of
wilderness
and let more trees really mature.
We
have enough evidence to know the effect of continued deforestation will
be
less rain, dried up land and vegetation, disappearing wildlife, less
diversity,
less beauty and less life.
In
1998 Cambodia declared deforestation their greatest environmental threat.
Thailand
banned logging, but is weak on enforcement
We
are using fresh water faster than nature can replenish it.
What an
astounding
time to be slowing the rate of that replenishment by removing so
much
of our forest cover and decreasing the size of trees.
The longer we
continue
forestry-as-usual the more damage we do to the natural water
cycles.
To improve the situation the end of commercial logging on our
National
Forests would be a good start, or at least making the Forest
Service
environmental impact statements account for water loss to down wind
areas.
And enough road building through forests!
The fur industry ran out
of
beaver, too many buffalo tongues and hides were taken, now our forests
are
going on a world wide scale. Yes the earth's land mass could easily end
up
treeless and bone dry if we continue sleepwalking.
When
I explained this deforestation/drought situation
to Steve Small Salmon
from
the Flathead reservation in Montana he said his elders used to teach
that
the forests give us life. They obviously had more in mind than wild
game
and berries.
Protect
and restore forests.
Tim Bacon, Retired forester