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Forest succession
Name: David H Khaliqi
Status: Other
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
What is forest succession?
What is the first species of conifer that moves in to a disturbed ecosystem?
Replies:
I do not think one can generalize regarding a particular species moving into a
disturbed ecosystem for the entire planet, the hemisphere or our country or
even a part of our country. You will notice that there is a great diversity
of species in the various forest types throughout the world. The actual
pioneer species to move into a disturbed area will vary according to location,
the indigenous species of that area, and the nature of the disturbance. One
generalization that can be made: if you know which species are growing in an
area, and can list them according to tolerance i.e. is the plant tolerant to
shade, you can develop a pretty accurate list for that particular forest
ecosystem.
For example, in my area here in southeastern Pennsylvania, our
mature forests consist of oak, maple, and hickory. These are all shade
tolerant species. This means they will do well in shade created by taller
trees, and they therefore can compete for sunlight in a mature forest with
some success. Species like birch, for example, do not like shade, and
therefore cannot compete in a mature forest with more shade loving trees.
After a disturbance, however, canopy is opened up (depending on how serious
the disturbance is) there would now be sunlight available and species such as
the birches would be able to develop in the sun. Naturally, if there are no
birch trees nearby to provide seed, you wont see birches arriving. Other
considerations would be available water and ground nutrition, again this would
depend on the disturbance.
There are many books available which discuss forest regeneration and success
succession. Let me know if you would like some book suggestions. Finally,
your original question asked which conifer species might be the fir first to
move into a disturbed area. If you could list the species of conifers in the
ecosystem you are theorizing about, according to how aggressive they are, and
whether they prefer (or require) sun or are shade tolerant, you can prepare an
expected forest succession plan for that ecosystem. Some considerations:
white pine likes a lot of sun when it is young but will tolerate shade when it
is older. Spruces will tolerate shade at most any age.
If the forest
ecosystem you are discussing has only spruces and white pines available to
supply seed, I would bet on the white pine as an early colonizer. Something ,
finally, which might cloud the picture a bit: since spruces will tolerate
shade, often you find many young spruces in the shade of a mature forest.
When a disturbance happens they already have a head start in reclaiming the
forest. Naturally if the disturbance is a fierce wildfire, many of them would
be killed.
If, however the disturbance is a thinning operation by a logging
company, the white pine seeds (assuming there are some available) might BEGIN
to grow since the canopy would then be opened and allow more sunlight.
Rickru
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Update: June 2012
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