permaculture

["Scott Pittman" <scott@permaculture.org>]

Tree leaves harbor a bacillus, Pseudomonas syringae, that is a nucleating
agent for ice crystal formation in clouds so in effect seed the clouds to
encourage rainfall.

Additionally trees act as condensers of moisture, particularly at night
where cool moisture laden ambient air is condensed on warmer leaf surfaces
where it is collected and drips to the ground below.  

There is a reason that a treeless desert produces no rain.

By cooling the soil surface and adding biomass to blanket the soil trees
discourage evaporation and encourage soil moisture retention.  The
subsequent cool, moist environment is a perfect situation for fungi to
thrive and build good soil, provide nutrients and water to trees, as well as
act as a water storage in the soil.

Scott Pittman
Director
Permaculture Institute
www.permaculture.org

-----Original Message-----
From: permaculture-bounces@lists.ibiblio.org
[mailto:permaculture-bounces@lists.ibiblio.org] On Behalf Of Jennifer Nazak
Sent: Wednesday, August 20, 2008 10:39 AM
To: permaculture@lists.ibiblio.org
Subject: [permaculture] How do trees make rain?

Hi All,

Here in central Texas, some land-owners are being paid
$350 per acre to clear cedar trees from their land,
the reasons being that the trees "suck up water" and
"aren't native." Furthermore, I've heard that the
felled trees are being BURNED, rather than being used
to create berms or harvested as wood, mulch, sawdust
for compost-toilet cover matter, etc.

I believe that a permaculture perspective would be
useful here, and have been casting my memory back to
the various PC courses I've taken. We all know that
trees put moisture into the air via transpiration;
I've read that 60% of inland rainfall is believed to
be generated by trees. 

What I'm trying to recall is, what are some of the
other ways in which trees can cause rain? I seem to
remember hearing, from Scott Pittman and other
esteemed permaculture sensei, that trees release some
substance that seeds the clouds, but can't find
mention of it in my written materials. And do grasses
and other plants release a similar substance? 

Any insights on the value of trees in generating
rainfall would be helpful to us in approaching public
officials about this policy of clearing cedars from a
drought-ridden land.  

cheers,

jenny

*   *   *   *   *   *   *

Permaculture Design Course in Austin - 10 selected weekend days Sept 27-Nov
22
Other classes and events throughout the year

Austin Permaculture Guild
512-619-5363 / austinperm@permie.us
www.permie.us


      
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