gypsum+ tree decline

YankeePerm at YankeePerm at
Mon Sep 22 08:17:18 EDT 1997

Bravo to Jack Rowe's excellent piece on gypsum.  He appears to be saying that
gypsum results in improved soil tilth.  Gypsum is calcium sulphate and is
used where people want to add calcium without raising pH (or when you score
some gypsum board on trash day.  It makes excellent sheet mulch, pH
requirements then being beside the point.)  Limestone, calcium carbonate, has
long been known to improve physical qualities of both clay and sand soils,
helping both to aggregate.  Calcium carbonate is a loose association of
calcium oxide, or lye, with carbon dioxide.  To oversimplify the matter,
stronger acids displace the carbon dioxide in the soil.  The lye then forms a
salt with the stronger acid.  Eventually some of the carbon dioxide falls
back down as acid rain.  CO2 is very soluble and rain tends to pick it up
rapidly.  (Which is why CO2 in the atmosphere hasn't built up much faster--it
ends up in the oceans and at certain concentrations, temperatures, and
pressures precipitates as calcium carbonate to be laid down for the next
tool-making species to abuse.  I'm not sure how calcium sulphate is formed
and therefore how renewable it may be.  Since sulphuric acid does not outgas
much at earth surface temperatures, both halfs of the salt stay around and no
pH effect is noticed.

The problem is that both materials, gypsum and limestone, come from strip
mines.  Therefore we are ripping off some other place on Earth when we use
them to tune up our own little patch.  I think that using these materials as
an aid in establishing a self-maintaining syetem can be justified.  The
problem comes if we design management approaches that rely on them
perpetually. Since this occassions perpetual work and damage, this is a type
one error, and thus not permaculture by definition.

I have similar concerns about the use of rock dust for remineralization,
except where it is obtained as a byproduct for something which we do not make
more viable by removing the dust.  

Regarding forest decline from acid rain, it is not just conifers that suffer
from acid rain.  As early as 1983, forest geneticists were concerned that the
sugar maple may be moving toward extinction.  The next year, I invented the
Tree Bank, as program of living trees in areas of minimum pollution, to start
from seed genetic reserves of forest trees threatened by pollution (as a
death blow following many kinds of ecological damage).  Moreover, the damage
is not just in the US northeast and Canadian southeast.  I've seen it in the
Rocky Mountains and thence eastward with rare pockets of health, which I
documented photographically so people would have a chance to see what healthy
trees look like.  We are children growing up in a leper village.  We think
leprosy is normal and healthy because we've never seen anything else.

WorldWatch Institute reports that decline is a serious matter around the
temperate Northern hemisphere.  I've seen identical symptoms in the tropics,
for exampla around Penang and Manila, and even in New Zealand, down wind of
Aukland.  This is NOT a problem limited to a few trees in one place.  Ten
years ago I was cutting firewood for a woman in the watershed of the Quabbin
Reservoir, which is the entire water supply for greater Boston.  Only one
species, black birch, which is a boreal species, was successfuly reproducing.
 Even staghorn sumac was stressed.  I've seen places in New Jersey where
light hungry ailanthus was coming in under sugar maple, which in health sades
out everything except beech and itself.  I've watched healthy trees in land
that owns me in the foothills of the Berkshires wither into deformed
caractures of their species.   This is not a minor problem.  In the plains,
it is greatly compounded by herbicide drift which can cause the trees to
explode in a rotting mass in slow motion.  Drought stress and widespread use
of semi-adapted exotics on the plains also contribute their share I'm sure.
 In Ireland, I was told they did not have the problem but that was fantasy.
 I saw it and reports of understory trees suddenly becoming dominant were
most simply explained by canopoy breakdown from pollution as a culminating

Folks who live in the sugar maple/black maple range have a chance to help
save trees.  Tree Bank is collecting seed of these species this species, as
well as Canadian Hemlock which has a smilar range.  The sugar/black maple
species (which we we regard as two types of the same species for our
purposes) range from the Maritimes past Ontario westward and south reaching
Georgia, where I have seen it, and Alabama, where I have not.  It is fairly
common in western North Carolina, for example, which will surprise most

I've not passed on the Tree Bank torch. For details on how to collect and
process and care for seed until shipping, contact Mike Janssens at
whiteoak at   He is now Tree Bank Seed Coordinator  for North
America.  Seeds should start ripening in some parts of the range at the end
of this month and will continue to be available until December sometime,
depending on locale and weather.  Canadian hemlock, T. canadensis, is now
ripe throughout much of its range.  A little Carolina hemlock mixed in wont
hurt anything, but try to keep the selections relatively clean.  More seed is
better than less, as we are trying to preserve genetic diversity and by the
time the seeds get used for reforestation in New Zealand by TreeBank Trust
Ltd. the germination is not fantastic.  Usually trees need to be treated to
prevent introduction of pathogens.  

I'm willing to handle a reasonable number of questions regarding the
philosophy and strategy of Tree Bank and concerns about the ecological wisdom
of exporting seed to another place.  The ecology of New Zealand, which so far
is the only recipient country other than a few red maple seeds to Mexico, has
been safeguarded and we have strongly encouraged TreeBank Trust to make their
native bush their first priority.  Best to write your questions  to me via
the mailing list so that I do not answer the same question 100 times.  At
some point I'll have to stop.  We also publish, through Yankee Permaculture,
an information packet of materials on this subject, all of which have been
placed in public domain.  That is for the .01 percent of people who still
have scruples about stealing from authors as they are the ones we want to
reach anyway.  

For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since
1982), Elfin Permaculture workshops, lectures, Permaculture Design Courses,
consulting and permaculture designs (since 1981), and now correspondence
courses via email.  Next starts in Oct. 1997. Internships available.
Copyright, 1997, Dan & Cynthia Hemenway, P.O. Box 52, Sparr FL 32192 USA
 YankeePerm at  

We don't have time to rush.

More information about the permaculture mailing list