| Dear
EarthTalk: Which trees are best to plant to help
combat global warming?
-- Tim C., Perrineville, NJ
Trees
are important tools in the fight to stave off global warming,
because they absorb and store the key greenhouse gas emitted
by our cars and power plants, carbon dioxide (CO2), before
it has a chance to reach the upper atmosphere where it can
help trap heat around the Earth’s surface.
While
all living plant matter absorbs CO2 as part of photosynthesis,
trees process significantly more than smaller plants due to
their large size and extensive root structures. In essence,
trees, as kings of the plant world, have much more “woody
biomass” to store CO2 than smaller plants, and as a
result are considered nature’s most efficient “carbon
sinks.”
According
to the U.S. Department of Energy (DOE), tree species that
grow quickly and live long are ideal carbon sinks. Unfortunately,
these two attributes are usually mutually exclusive. Given
the choice, foresters interested in maximizing the absorption
and storage of CO2 (known as “carbon sequestration”)
usually favor younger trees that grow more quickly than their
older cohorts. However, slower growing trees can store much
more carbon over their significantly longer lives.
Scientists
are busy studying the carbon sequestration potential of different
types of trees in various parts of the U.S., including Eucalyptus
in Hawaii, loblolly pine in the Southeast, bottomland hardwoods
in Mississippi, and poplars in the Great Lakes. “There
are literally dozens of tree species that could be planted
depending upon location, climate and soils,” says Stan
Wullschleger, a researcher at Tennessee’s Oak Ridge
National Laboratory who specializes in the physiological response
of plants to global climate change.
Dave
Nowak, a researcher at the U.S. Forest Service’s Northern
Research Station in Syracuse, New York has studied the use
of trees for carbon sequestration in urban settings across
the United States. A 2002 study he co-authored lists the Common
Horse-chestnut, Black Walnut, American Sweetgum, Ponderosa
Pine, Red Pine, White Pine, London Plane, Hispaniolan Pine,
Douglas Fir, Scarlet Oak, Red Oak, Virginia Live Oak and Bald
Cypress as examples of trees especially good at absorbing
and storing CO2. Nowak advises urban land managers to avoid
trees that require a lot of maintenance, as the burning of
fossil fuels to power equipment like trucks and chainsaws
will only erase the carbon absorption gains otherwise made.
Ultimately,
trees of any shape, size or genetic origin help absorb CO2.
Most scientists agree that the least expensive and perhaps
easiest way for individuals to help offset the CO2 that they
generate in their everyday lives is to plant a tree…any
tree, as long as it is appropriate for the given region and
climate. Those who wish to help larger tree planting efforts
can donate money or time to the National Arbor Day Foundation
or American Forests in the U.S., or to the Tree Canada Foundation
in Canada.
CONTACTS:
American
Forests; National
Arbor Day Foundation; Tree
Canada Foundation
PHOTO
COURTESY OF GETTY IMAGES
Due
to a lack of federal support, the onus for bolstering environment
education in grades K-12 has fallen on local schools, school
districts and individual teachers.
Dear EarthTalk:
Does environmental education figure prominently in classrooms
these days? By that I mean not just science but an understanding
of key issues and environmental stewardship.
-- Mary Swan, Framingham, MA
Environmental education
has long struggled for legitimacy alongside more traditional
disciplines within the liberal arts and sciences. But “environmental
literacy” studies in the late 1980s revealed that schoolchildren
lacked basic knowledge about the natural environment. This
convinced the U.S. Congress to take action, and in 1990 they
passed the National Environmental Education Act, forcing the
Environmental Protection Agency (EPA) to strengthen and expand
environmental education nationwide through education and teacher
training and the administration of grants to exemplary programs.
While many of the
programs since developed by the EPA have been lauded as exemplary,
a lack of funding has prevented many ideas from moving forward.
According to a National Environmental Education Advisory Council
report, between 1991 and 1996 the EPA received 10,000 environmental
education grant applications totaling $300 million, but was
only able to fund 1,200 totaling $13 million. Continued shortfalls
at the EPA under the current Bush administration have forced
further cutbacks.
With such a lack
of federal resolve, the onus for teaching kids about the environment
has fallen on local schools and individual teachers. According
to the President’s Council on Sustainability, because
environmental education is multi-disciplinary, it is hard
for teachers to work it into their narrowly defined lesson
plans. Also, most teachers are not trained in environmental
subjects. As a result, non-governmental organizations have
become increasingly involved with classroom environmental
education efforts.
One such organization
is the North American Association for Environmental Education
(NAAEE), a network of volunteers that provides guidelines
and resources for educators and parents who want environmental
education for their K-12 students. According to NAAEE’s
Mary Ocwieja, the group takes a “cooperative, non-confrontational
and scientifically-balanced approach” to education about
environmental issues. NAAEE’s website, EE-Link, lets
users find resources on just about any environmental topic.
Another organization,
the National Environmental Education & Training Foundation,
which was chartered by Congress in 1990, sponsors ClassroomEarth.org,
a free website that calls itself “the best of the best”
collection of environmental education programs and resources
for K-12 teachers, parents and students. The site helps educators,
after-school programs and home-schooling parents find up-to-date
information on the most successful, well-tested and effective
national environmental education programs available today.
According to NAAEE,
their work and that of similar organizations is starting to
pay off. Some 61 percent of U.S. K-12 teachers surveyed in
1999 claimed that they include environmental topics in their
curriculum, with some devoting hundreds of hours of classroom
time annually to environmental issues.
CONTACTS:
NAAEE;
Classroom
Earth
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