On Tue, 1 Nov 1994, Mike Sonntag wrote:
> How does a suppressed tree know that it is suppressed?
> Consider the following (hypothetical) situation: You have two
> indentical clones of, lets say, spruce. The first (A) you plant on a
> site in e.g. montane Germany under an existing canopy. The
> other (B) you plant e.g. in Finland on an open field. The sites are
> such that the amount of radiation, climate (temperature,
> precipitation and soil are for both clones identical. So if both
> clones come out they both experience the same climate, soil etc..
> Now both trees should grow in the same way, but experience tells you
> that the suppressed spruce A will grow in a different way than B,
> meaning A will grow more in height than B, and less in diameter.
Although the regional radiation, climate and soils may be very similar
(never identical), the local microclimate caused by differences in
vegetation (closed canopy forest versus open grassland [?]) will
result in the differences in growth form and amount. Under the canopy
a spruce clone will experience differences in light amount and
probably light quality. In addition the temperatures will be lower
and relative humidity will be higher under the canopy than compared
with the open area where wind is more free to blow and capture
moisture from the soil. Solar radiation at the level of the spruce
clone in the open will be more intense resulting in greater
evapotranspiration from that clone compared with the clone under a
canopy that only gets filtered sunlight and occasional sun specks.
BobK
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# Bob Keeland, Ph.D. FOREST ECOLOGIST #
# NBS, Southern Science Center PHONE: (318) 266-8663 #
# 700 CajunDome Blvd. FAX: (318) 266-8592 #
# Lafayette, LA 70506 INTERNET: keelandb@nwrc.gov #
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