Larry Caldwell writes:
In article ,
writes:
The notion of clear-cutting huge tracks of forest to increase runoff for water
containments is not only self-serving industry pandering, but delusional.
snip
Do you have any actual research to back this position? Generally I am of
the opinion that any ground that can grow trees should be growing trees,
but in some areas of the world trees are discouraged because of the
amount of water they use. I have talked to a farmer in South Africa who
was not allowed to plant trees in a riparian zone because of the amount
of water they would consume.
I think the idea behind this scheme only would apply to east slope areas
that are prone to chinook winds. I recall several studies in Alberta
that showed a net moisture gain from an east-slope area that had a
patchwork of small clearcuts. I don't have any references handy, but
might be able to find them if anyone is interested.
The mechanism was that all the winter snow in the small clearcuts reached
the ground and was protected from evaporation by the surrounding trees,
while the undisturbed area lost about 1/3 of the snow moisture to
evaporation over the winter, as almost all the snow held in the crown
branches evaporated. This effect was lost in openings over about 20 ha
in size, because the sheltering effect of surrounding bush was lost in
larger openings.
I have no idea what effect on the downwind water cycle this might have
if undertaken on a large scale.
--
Larry Stamm
http://www.larrystamm.com