larryc at teleport.com
Sat Feb 1 03:58:25 EST 1997
In article <199701310557.AAA54386 at r02n05.cac.psu.edu>,
John Skillman <jbs11 at psu.edu> wrote:
> Agroforestry, as considered by the ICRAF (International Council for
> Research in Agroforestry) is a part of the agriculture-forestry
> continuum with interfaces between annual crops, trees, and often
OK. This is appropriate. One of the reasons for converting some of
my property to tree plantation is because of the effect of livestock.
The area has previously been used as cleared pasture, but is approximately
on a 100% slope. Hoof action by the animals was contributing to rapid
erosion. Every time a cow took a step, a pound of soil moved six inches
The area where I live has a climate very similar to ancient Greece, say
around 1500 bce. The hills and mountains are very steep, but forested
and have a good layer of topsoil in most places. Loss of timber cover
or conversion to livestock pasture accelerates the erosion process.
Obviously, there is little prospect for planting a cultivated crop
on land that steep. Economics at this point would not support such
an effort on an annual basis. The advantage of forestry on the site is
that it only has to be done every fifty years or so. Perhaps in fifty
years, food prices will have recovered enough to put the land back
into food production. If so, there will at least be a topsoil
accumulation to work with.
> The model agroforestry system which many people are familiar with is
> "traditional" coffee cultivation where the coffee shrubs are grown under
> trees. The trees may be monospecific or may a mixture. One outcome of
> research on this model system is that the greater the mixture of tree
> species grown in this managed system the more structurally complex it is
> and consequently the greater the number of non-plant species that can be
> found there.
I'm afraid I haven't noticed any postings to bionet.agroforestry in
Portugese. I did see one Spanish posting recently, but it was someone
trying to recover some chemical from pressboard and moldings. I'm
on ag mailing lists with considerable input from South America. They
may not write good English, and we may not write good Spanish or
Portugese, but if we have something to say to each other we manage.
One of the great problems with academics is that they are actively
hostile to people who work in their specialties. I suppose academics
are paid to be experts, and find it embarrassing to be ignored, or
even laughed at. It's the nature of academic studies to narrow the
scope of investigation as much as possible. Unfortunately, neither
farming nor forestry are so narrowly constrained.
The big advantage of drawing experienced people into the conversation
is that you learn things not covered in the scope of research. Given
your example above, I come up with a number of immediate questions.
The added diversity would seem predictable. What do the "non-plant
species" (wow, a new euphemism) eat? How many of them eat coffee berries
or leaves or roots? What effect does this have on production? What
is the cost of converting to multiple species plantations? How often
are plantations logged? What is the return on timber compared to return
on coffee over the lifetime of a plantation? What happens if trees die/
blow down/fall over/get sick? What questions should I be asking? Can
this model be expanded into a temperate zone rainforest?
> More and more coffee is grown in monoculture plantations (no
> trees) requiring greater inputs of fertilizer (fast growing sun plants
> require more nutrients then slow growing shade plants) and pesticides
> (forested coffee plantations presumably support greater numbers of birds
> and beneficial insects that keep the insect pests in check). The
So the multiple species plantations can't compete? I assume one of the
big problems is the length of time it takes a forest canopy to develop,
plus the siphoning of fertilizer inputs by the trees. It would be
interesting to talk to someone growing a plantation like this to hear
what problems they are experiencing. It's too bad that they don't
participate in this group. It's surprising sometimes how much can
be learned from farmers in other climates and other countries.
> So yes, agroforestry is quite distinct from forestry as conventionally
> practiced in the US and Europe. It is not about growing trees like a
> field crop but rather growing trees with field crops. Consequently I
> suggest that individuals that are interested in forestry issues
> establish their own foretry newsgroup.
This seems to be a bit of a non sequitur. There seems to be very
little interest in agroforestry discussion on this group. It would
also seem that before you can co-crop trees and whatever, you have to
grow trees. They do, after all, take longer to grow than most food
It's also hard to tell what you mean by "conventional" forestry. I
assume you mean national forest lands where nobody lives. That is
forestry as practices 30 years ago, and I don't have much interest in
talking about it either. However, private forest holdings in both the
USA and Europe often have to serve double duty in producing an annual
income in addition to long term forest production. That would seem to
be the quintessence of your definition of agroforestry.
One mailing list I subscribe to is a New Zealand style Management Intensive
Rotational Grazing (MIRG) list. MIRG is a low-input, sustainable form
of animal husbandry. You might be interested to know that MIRG
practitioners recommend cutting down all the trees in the pasture. The
reason is that during hot weather, cows will cluster in the shade, chew
their cud, and crap. Trees are manure magnets that siphon fertility
out of pasture and concentrate it around the roots of the trees. When
you are practicing a no-fertilizer closed system agriculture, this
It would be interesting to hear from someone with an open stand of timber
who would put a rising plate meter on the grass and calculate DM/ha.
I may someday move cattle or sheep back into my plantation, after the
trees get above the browse height. Meanwhile, the trees are a crop just
like a field of wheat. I don't have any more qualms about cutting up
a tree than I have about cutting up a cow.
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