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SOME PRINCIPAL AGENTS OF TROPICAL DEFORESTATION
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With fields as rocky as this one routinely being
farmed, it is apparent that many farmers
experience a lack of access to
good farmland.
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Possible Solutions
What Can Be Done?
While slash-and-burn farming is the proximate agent of
much deforestation in the Selva Maya and elsewhere in the
tropics, it is not accurate to view this farming activity as the
ultimate cause of deforestation. The phenomenon of a
constant flood of landless immigrants into remaining forested wild lands
in order to eke out an existence of subsistence
farming is a symptom of broader social conditions that very
often involve skewed patterns of land ownership, poor standards
of education and health care, lack of employment, and other
indicators of under-development. This is a difficult problem
because consideration of it inevitably leads to discussion of
politically sensitive topics such as agrarian
reform--redistribution of land ownership. However, failure to
realize that this very topic has been at the root of much
political turmoil in Latin America is to doom us to continue
repeating the past.
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One long-term strategy possible with
secure land
tenure is planting of
valuable hardwoods such as mahogany.
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Many conservation and development workers believe that if a
peasant family can acquire secure title to a piece of land,
their mode of managing that land generally shifts toward
activities permitting long-term sustainability, as opposed to
the cut-and-run mentality that often pervades along the tropical
forest frontier. Hence, many programs aim to assist landless
families in securing title to property.
In addition to providing secure land tenure, improvements in
farming methods can go a long way toward decreasing the need of
farmers to constantly rotate into primary forest, felling it for
cropping purposes. Any technology that aids farmers in
maintaining productive, cost- and labor-effective cropping on
the same acreage over extended periods of time should be an aid
in saving forest. While it would surely be possible to achieve
this by pouring on expensive fertilizers, herbicides, and
insecticides, this is not an advisable strategy for many
reasons, perhaps chief being that farmers cannot afford such
costs.
Much more appropriate is the use of "green manure"
cover crops--nitrogen-fixing plants--often legumes
(members of the pea family). Such plants, through the aid of
nitrogen-fixing bacteria in root nodules, take N2--diatomic
nitrogen, which is not usable by plants--from the atmosphere,
and "fix" it as ammonia, which is then converted by
certain soil bacteria, first to nitrite and then to nitrate,
thereby enriching the soil with this important plant nutrient in
a form chemically available to plants. Such green manure cover
crops also add organic matter to the soil, improving soil
structure and nutrient-retention capacity.
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The seeds of change: frijol abono (Mucuna
sp.), one
of many nitrogen-fixing cover crops that enrich
soil while
helping combat weeds, allowing
sustained cultivation of the same acreage.
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Green manures often have an additional benefit beyond simply
enriching the soil--that of weed suppression. As noted above,
the increase in weeds under cultivation is a primary rationale
for abandoning one field and moving on to fell additional
forest. Green manures can often be managed by the farmer so as
to create a dense, low ground cover that aids greatly in
controlling weed problems.
Our Research and Outreach
Because of the importance of shifting cultivation as a
deforestation agent in the Selva Maya and elsewhere, a great
deal of our research dealt with this land use. We investigated
the habitats created by this style of farming, and the ability
of various faunal groups to use these habitats. We examined
faunal use of the small forest patches remaining in such farming
landscapes. We investigated the ability of green manure cover
crops to increase corn yields and permit sustained cultivation
on the same acreage in our study area, and quantified in part
the conservation gains that would be obtained if all farmers
ceased cutting primary forest, through use of such cover crops.
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Chindo Garcia, Peregrine Fund extensionist,
examines
a thriving stand of frijol abono.
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Based on all the above, we examined the desirability of
different policies toward shifting cultivation. Finally, we
attempted to save forest habitat in our study area by
introducing farmers in a few small villages to the use of green
manure cover crops. Results of our activities
are presented
under the section --"Maya Project Activities and
Results."
 Literature
Cited, Shifting Cultivation
and Hunting in Tropical Forests.
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