News briefs on the solar potential of polar bears, wild mushroom clouds, undercover crops, air-bag pollution, mulch, cattle and sheep grazing together and an adopt a whale program.
Solar Polar Bears
The polar bear is a nearly perfect solar converter, says
electrical engineer Richard Grojean of Boston’s
Northeastern University. The bear’s fur appears white
because it reflects visible light, but in fact polar bear
hairs are transparent and hollow. They trap ultraviolet
radiation and conduct it, like light within an optical
fiber, to the bear’s skin–which is black. The energy
is then absorbed and helps maintain the animal’s body
temperature. Unlike solar collectors that must be aimed for
maximum gain, polar bear hairs trap light coming from any
direction. And the animals lose very little heat; the
ultraviolet energy flows only in one direction: toward the
animal’s skin, never away from it. Grojean believes that
similar principles can be applied to designing efficient
solar collectors for use in cold climates.
Overpicking Mushrooms – Wild Mushroom Cloud
Much to the dismay of mycologists and wild-foods foragers,
the demand among gourmets for wild mushrooms is bringing
more and more full-time pickers from U.S. and foreign food
companies into the fungusrich forests of the Northwest.
According to a biologist with the Washington Department of
Natural Resources, the annual harvest from that state alone
is now no less than 1 million pounds. Although no studies
have been conducted, some scientists fear that
over-harvesting, combined with the destructive impact of
heavy foot traffic on the forest floor, may endanger some
mushroom species. Also threatened are the trees that have a
symbiotic relationship with mushrooms, drawing nutrients
from the fungi that grow on and in their roots, trunks, and
limbs.
En-gendering Failure
Agricultural training programs designed to help the people
of African nations learn better ways to feed themselves may
be doomed . . . simply because many of the programs are
training males to do work for which, by cultural tradition,
females are responsible. According to the International
Children’s Centre, African women do the vast majority of
agricultural tasks: 50% of the planting, 70% of the hoeing
and weeding, 60% of the harvesting, 80% of the storing, 90% of the processing, 60% of the marketing, and half of the
chores involved in managing livestock. Yet only 10% to 20% of the participants in agricultural training programs are
women, leaving the likelihood that much of the instruction
will be wasted on male students who will never use their
training.
Undercover Crops
Orchards with cover crops, or even weeds, growing between
trees suffer less damage from harmful insects than “clean”
orchards, say researchers at the University of California’s
Division of Biological Control. The scientists planted bell
beans, vetch, rye, clover, or mixed weeds in some test
orchards and disc-cultivated others. The cover-cropped
groves had fewer aphids, leafhoppers, and codling moths,
and had higher and more diverse populations of predatory
species. Apparently the vegetation initially draws pest
insects, providing them with food and shelter–but
they in turn attract predators that devour the harmful
types before significant numbers infest the trees. Some
cover crops–particularly long-blooming
legumes–seemed to foster especially high populations
of beneficial insects.
Air Bag Pollution
In a crash, the front seat occupants of a car equipped with
an air bag have a good chance of escaping severe injury.
When the wrecked car is towed to a junkyard for recycling,
however, the bag itself becomes a potential killer. Such
cushions contain an explosive chemical propellant, sodium
azide, which is a suspected carcinogen and mutagen. Listed
as dangerous under the federal Toxic Substances Control
Act, sodium azide is released if an air bag-equipped auto is
fed into a shredder (as most junked cars now are).
Recyclers say that finding a way to deal with air bags is
the toughest problem they face. Currently, they claim, the
propellant–and therefore the air bag in general–endangers the lives of thousands of workers
in the industry and may lead to air, soil, and groundwater
contamination in areas near shredding facilities.
Mulch Ado About Nothing
According to the USDA, an estimated 285 million pounds of
petroleum-based plastic film are produced each year for
agriculture, and about half are used for mulch. But because
plastic mulch isn’t biodegradable, it adds nothing to the
soil and must be routinely removed and disposed of at the
end of the season, an expensive and time-consuming process
that often creates environmental problems when the film is
burned or buried. Now scientists are developing a
starch-based film, made from surplus corn, that will
decompose naturally after a set period: say, the length of
a typical growing season. Although the film is still
several years away from commercial production, USDA
scientists believe it could eventually replace conventional
plastic mulches made from petroleum-derived chemicals.
Cattle and Sheep Together
Cattle, not poisons or fences, may offer western sheep
farmers the best way to protect their flocks from coyotes.
Cows and sheep grazing on the same range normally keep
their distance. But USDA researchers have found that when
45-day-old lambs and yearling heifers are penned together
for 30 days, the lambs form a strong social bond with the
cows and develop a need to be close to them. When turned
out to graze, the two species intermingle freely . . . a
fortunate arrangement for the mild-mannered sheep, because
cows distrust coyotes and unfamiliar dogs, and butt and
kick at the predators to keep them away. (Incidentally,
cattle eat mainly grasses, while sheep prefer broadleaved
plants, so the two can coexist on varied pasture nicely.
The infamous and bloody range wars of the Old
West–cattle ranchers against sheep farmers–were
totally unnecessary.)
Adopt a Whale Program
Researchers have found that the tail fins, or flukes, of
humpback whales–an endangered species–are as
different and distinctive as human fingerprints. As a
result, scientists have been able to identify more than
350 individual humpbacks. In subsequent studies, they’ve
found that each whale has a unique personality. Using that
information, the International Wildlife Coalition has come
up with an appealing method for raising funds to help save
the whales. For $15 or more, you can “adopt” a specific
humpback and receive a photo of that whale, along with an
“adoption certificate.” You also get a subscription to the
coalition’s quarterly publication, Whalewatch,
which includes updates not only on important conservation
issues but also on sightings of individual whales. For
additional information, a list of eminently adoptable
whales, and an application form, write to Whale Adoption
Project, International Wildlife Coalition, Falmouth, MA.
