>Forest fire kills pathogens (rot, insects, fungi); smoke kills
pathogens outside fire area breaks rocks through heating & cooling, which
builds soil, releases the nutrients phosphorus & calcium from leaf litter
into soil, stimulates growth of nitrogen-fixing plants,
allows individual trees and forest patches to survive, providing seed
source, wildlife habitat & old-growth features in new forest, leaves
standing trees, fallen logs & root networks, reducing sediment
runoff encourages conifer growth; heat stimulates cone opening, reduces
competition from hardwoods and ensures natural seed supply,
retains genetic diversity of tree species, allowing adaptation to new
conditions.
>
>Clear cutting allows pathogens to survive heavy equipment promotes soil
>rutting, compaction, erosion depletes site by removing nutrient-rich leaves
>& twigs discourages nitrogen-fixing plants, completely removes standing
>trees; changes wildlife habitat, seed source, old-growth features, clears
>site of trees, allowing high level of sediment runoff, stimulates
>shade-intolerant hardwoods by creating full sun conditions without heating
>soil; supports species conversion of forest drastically reduces genetic
>diversity in regenerating forest
Thanks for an excellent summary. To preface, I'm NOT an expert on logging,
just a concerned citizen. An ex-girlfriend did her MS on the effects of
logging on salamander community structure, and I 've had a few classes here
and there...
That said, in the southeast (and elsewhere), the debris is typically burned
off following a clear cut. A fire under these conditions burns hotter and
heats the soil deeper. This has several implications: the seed bank is
drastically reduced, (something owners like, because it reduces the number
of hardwoods that pop up in between the plantation pines), it increases soil
mineralization, which can facilitate erosion (it makes it more difficult for
ground cover to reestablish).
A historical tidbit- There's a high plateau in WV called Dolly Sods. It's a
really neat place, and was one of the last areas in WV to get heavily
logged. Pictures taken before logging showed huge spruce forests, and
minimal exposed rock. After cutting it, they set it on fire... it burned
1-2m of humus off the top of the mountain. If you go there now, probably
100yrs after the fire, the trees are low and scraggly, and set between huge
expanses of barren rock. A beautiful place, but nothing like it was.
Amazingly, a few populations of Cheat salamander (Plethodon nettingi)
survived the blaze.
Natural fires burn more quickly, and at a much lower intensity (even in pine
forests). It's amazing, but you can walk around in a recent natural burn,
and turn over logs and still find live salamanders, snails, etc. A lot of
the herbaceous layer survives after natural fires, as well.
Another important thing to realize is that worldwide, rotation time is
decreasing- and noone has bothered to adequately address whether you can
maintain 30-50 year rotations indefinately.
Cheers,
Dave
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