Conservation in the tropics and Prosopis: The allpurpose tree Paul R' Earl

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Conservation in the tropics and Prosopis The
allpurpose treePaul R. Earl
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Save the planet! OUR PLANET seems
to be drying out, and water wars not so far off.
The primary selection factor may become humidity.
The planetary extremes have always been ice and
sand, and resistance to desiccation is likely to
soon involve the genetics of crop plants.
Although the fight for food is perhaps more
obvious than the one for water, both exhibit the
Mathusian notion that geometrically increasing
demand exceeds arithmetically increasing supply.
Thus, overpopulation is accelerating.
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Sensitive actions like deforestation are rapid
and highly evident now, because of human
overpopulation. The Brazilian disaster was forest
fire for the benefit of the cattle industry.
Almost everybody knows these things and does
little about them, because they are not empowered
to act positively. But also, the public likely
does not understand the fragility of the ecology
involved and even contributes to green groups
embezzling money.
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Education and public health and add development
may well be poorly financed just because they
are not given priority. This is true of research
and also conservation. As we do not have the
direct power to make changes, we shall suggest
tropical legumes mainly for abandoned lands.
Peter Felker of Texas demonstrated the
applicability of mesquites to the lands they are
found on.
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How does Prosopis (mesquite) fit into rural
development?The use of trees as windbreakers in
arid lands is sufficient reason for promoting
them. Mesquites sometimes grow where nothing else
except cactuses can. However, the days when they
formed productive hardwood forests are over. By
desertification kindled by man, the days of trees
over 100 years old are over, mostly.
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The range for growth is governed by the
relative humidity and temperature. When the air
is dry, the stomata of the leaves close and
photosynthesis stops. Then individual biomasses
and new tree establishment are reduced. When the
air is moist, other species of shrubs and trees
will display successful plant composition.
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The rebellious sands are subdued and the
inhospitable soils are colonized. The dreary
scene of dry districts is changed to that of
green belts. The bleak treeless landscape is
painted with splashes of brown, green and yellow.
The monotony is broken for the traveler and the
sheep and goats munch and crunch happily on the
proteinous pods. The rural folk, whose lands were
getting buried under drifting sands are grateful
to the Forester and Prosopis, and the poor folk
who had no fuel to burn in their hearths now have
Prosopis. They collect the fuel in their leisure
and sell in towns for a descent price.
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The pod crop, browsing leaves and gathering fuel
have been mentioned. Charcoal for cooking and
fence posts and living fences along with fine
furniture including rich parquet floors are
attractive products. However, vegetation to
stabilize landscapes might be the most important
role for mesquites. The pod harvest might be
better appreciated, and timber in all forms
conserved and protected.
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Foliar morphology. By eye, mesquites
can only be told apart by their foliar
morphometrics. Prosopis has species only in
taxonomic dreams, since all or most cross.The
illustration of the mesquite Prosopis glandulosa
is for the description by John Torrey in 1828.
Influourescences of over 200 individual flowers
and pods are shown. The flowering parts of all
mesquites are similar. Torreys mesquite is from
Col. Longs creek, Union County, New Mexico,
USA
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The biological species concept depends upon
crossability. Regardless at present, the
taxonomic species is more popular. This means
that about 80 taxonomic species are taken as
real, although 2-3 or even only one biological
species exists (P. africana).
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The 5 measures of the leaves are a) LL length of
leaflet, b) LR length of rachis,c) PL number of
pairs of leaflets, d) PR number of pairs of
raches, ande) LP length of the petiole. LL, LR
LP are in mm, whereas PL PR are counts.
Either 1 or 2 PR are common, and the range is 1-4
PR. Four different races are shown in the
illustration. Other morphological characters like
has-or-has-not spines are almost worthless.
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If and only if different mesquites are grown in
a common garden can phenotypes and genotypes be
distinguished. Mesquites have not been
categorized into satisfactory species by any
means including the polymerized chain reaction of
DNA. Most of the mesquites of the Americas
cross. Convergence is a large unresolved issue.
When a niche in Chile is the same as one in
Venezuela and another in Mexico, expect to find
the same leaf design. Favored hybrids including
mutants are fixed by the niche.
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Some crosses of New World mesquites demonstrating
the high crossability among Prosopis. Tiny is a
new race from Sonora, Mexico.Similar leaf
designs found far apart are fixed by their niches
that are perhaps identical and do not necessarily
have genes acquired from common descent. Does
this sound like a Lamarckian argument?Plantations
like natural woods can slow down soil erosion.
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An ounce of prevention is worth a pound of cure.
This will not hold when the damage is inevitable.
Does this slogan relate to sustainability?
Sustainability only applies to opulent countries.
The harsh nature of the future ecology is being
vastly underestimated. Removal of woods changes
green to brown.
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Then a mesquite plantation while approved as a
step in the right direction may somewhat
alleviate aridity but not cure it. The
redistribution of water through
evapotranspiration by shrubs and trees is an
enormous benefit of this cover. The cover is
sometimes accused of using up water that it is
actually redistributed. Dimwitted people may
believe that mesquite-occupied areas are
adversely using all the water when the problem
can be human population/water.
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Prosopis microphylla, 15 m high, at Zumpango,
Guerrera, Mexico beside a seasonally dry
arroyo (stream). Maximum height of mesquite at
Lago Chapala, Jalisco, Mexico is 22 m.
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Summary. Standard commercial
forestry does not consider mesquites since
generally mesquite woods are exhaused by overuse.
They, in Felkers words, just hold the world
together. Mesquites represent a vital part of
the tropical world, because of their freatic
ability to gather water through times of drought
and store it. Storage means the shutdown of
biomass production.
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Summary (cont). They can grow a meter
in height per year if they get the water. They
provide browse, pod harvest and household fuel
wood. Vast arid territories support silvopastoral
systems. These lands cannot sensibly be converted
to crop lands, and must produce at low levels.
Although mesquite plantations may not be truely
profitable, their value as windbreakers is high.
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Summary (cont). A great problem is
enormous destruction by bulldozer landclearing
and fires. The common basis of desertification is
the futile attempt to grow crops when the native
vegetation cannot prosper. The final problem is
how to give higher values to arid lands, while
knowing that subsidies fail. Perhaps mesquite
product development can extend beyond poverty,
and improve the quality of life.