permaculture

["Lawrence F. London, Jr." <lflj@intrex.net>]

http://lists.ifas.ufl.edu/cgi-bin/wa.exe?A2=ind0905&L=sanet-mg&T=0&O=D&P=68080
SANET-MG Archives -- May 2009 (#94)
Subject:         QRY: Evidence of reforestation increasing rainfall?
From:   Chris Wardle <[log in to unmask]>
Reply-To:       Sustainable Agriculture Network Discussion Group <[log in to 
unmask]>, Chris Wardle <[log in to unmask]>
Date:   Wed, 27 May 2009 20:41:39 +0500

I'm running into a research stumbling block and wonder if this
somewhat public musing could tap into the greater wisdom accessible
through cyber-networking?

But first some background ...

A month or so ago I was doing some bushwalking in the North-East of
Pakistan's Balochistan Province, with one of my younger
brothers-in-law, Danish. As we reached the top of a large mesa-like
hill called Dhera and looked out at his - and my beloved's - home
village of Phugla to the north, we were struck by how few trees we
saw.

This got us to chatting about climate change, the area's potential for
agro-forestry, and the possible impact of large scale tree planting on
the weather pattern.

Within twenty kilometres to the northwest, native Olive trees thrive
in the area's sandy soils and hot summer, which prompted me to ask,
"With a similar climate and soil, why don't people look to plant
commercial Olive varieties here?"

It was a question we later repeated with community members and their
answers seemed to confirm our prediction that it rested somewhere
between:

* a lack of awareness,

* an unwillingness to collaborate or experiment, and

* no patience to wait for the long-term gains offered through agro-forestry.

Well, these are challenges we’ll return to another time, but as we
discussed climate change, Danish noted that there was much more
reliable rainfall fifteen to twenty years ago and remarked that if
tree loss accounted for a decrease in rainfall, would reforestation
improve the rainfall pattern and how much effort would people have to
put in, to effect real change?

"Specifically," he asked, "how many trees would every person in this
community have to plant, in order to increase our rainfall - five,
ten, fifty trees each?"

In answering I said I didn't know, but thought it might be in the
order of thousands, but that was just a very rough guess and I would
go and find out for him.

So, after a very long introduction, here's my question:

Is there any well-documented evidence that reforestation mitigates the
negative impacts of climate change by increasing rainfall, and on what
sort of scale do we begin to see such effects, if they exist?

When I look at policy-level climate change mitigation strategies, I
consistently read that we need to plant more trees, but this seems to
be based on documented evidence of tree loss. Sure, there is evidence
that tree planting decreases erosion and increases soil moisture
retention, but I am yet to find references to positive rainfall gains
from reforestation.

Please don't get me wrong, I'm very much on board with this issue. In
the previous century I've encouraged and worked with my children on
community tree plantings in my home town of Darwin and on saving the
one remaining remnant of tropical rainforest on the fringe of Darwin
city - the Duke Street Rainforest. More recently, my beloved Maha and
I spent four wonderful months of joyful, practical learning during our
voluntary permaculture internship on an organic coffee plantation in
Nepal.

In my heart of hearts and from my permaculture training, I feel that a
reforestation strategy should work to increase rainfall, but my
attempts to uncover hard evidence keep running into a brick wall.

Maybe I'm not using the right search terms or looking in the right
places, so I turn to you, dear reader, for guidance and possible
permaculture solutions and research experience in this regard.

Thanks in anticipation of your kind responses and my apologies for
cross-posting.

Looking forward to hearing from you in due course and wishing you
salaams from Quetta,

Chris Wardle.
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