permaculture

["Kirby Fry" <peace@totalaccess.net>]

Hi Wes,

>>  One solution suggested is to clear 200 square kilometers of trees from
the catchment area.  <<

Didn't the Romans used to protect the wooded watersheds above their cities,
both to ensure clean water and prevent landslides, etc?  Now we're in such
dire straights that we're competing with the trees for water.  It seems self
defeating if indeed trees really do create rain.  (I'm still looking for
documentation on this)

What else is the municipality doing to conserve water, I wonder?  Are folks
allowed to water lawns?

>>  It saddens me that we have to contemplate this sort of action. The loss
of animal and bird habitat and at this scale it could even reduce the
rainfall.  <<

Now this is one of those paradoxical situations where someone might argue
that if a tall grass prairie were encouraged instead of a forest, you would
actually increase biomass, biodiversity, the carbon sinking capacity of the
system, and increase rain through-fall and water infiltration by decreasing
evapo-transpiration and evaporation.

I guess my point is that, even though you can tick off all of the advantages
of knocking back a woodland and replacing it with a grassland, there's still
something that doesn't bode well with me.  For starters there's the
maintenance issue.  How is your municipality going to keep the watershed as
a grassland - mowing, burning, grazing?

>>  In most other places in Oz removal of trees has increased to level of
aquifers, they have risen up through layers of salt to be close to the
surface. Ground evaporation then concentrates these salts in the top soil.
It has been estimated that we will loose one third of productive land in the
next twenty years unless drastic action is taken to lower the water tables.
<<

Is your watershed at risk of this happening once the trees are removed?  If
so, how on earth can folks contemplate such drastic action?

>>  Just to explain further, trees absorb perhaps 80 percent of rain fall,
drainage into aquifers could be as low as 5 percent, Grass land only absorbs
15 percent of rainfall with aquifer recharge of perhaps 70 percent, the
figures will vary depending upon climate and species and topography etc but
I guess you can get the picture.  <<

Yes, that trees absorb and transpire water surely seems to be to their
detriment these days.  When the earth was more humid this was probably
viewed as a great advantage, helping to moderate ground water conditions.
Now with our western allopathic world-view competition is seen as a
dominating natural force, cooperation as some sort of green myth, and
conditions such as trees using water are simply remedied by eradicating the
trees!

Please tell us Wes, that you know of some better solutions for the
predicament of your watershed.


Kirby Fry

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