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Fire/logging for stable forest ecosystem?

Steve Cumming stevec at unixg.ubc.ca
Thu May 5 14:04:02 EST 1994


In article <1994May4.191630.7944 at news.brandonu.ca> neufeld at news.brandonu.ca writes:
>
>[queries re B.C. logging]
>
>1. Selective logging can be detrimental to the forest gene pool.
>
>When only the largest, straight, prime specimens are removed from a
>forest, [is bad, so]
>the optimum harvesting practice would seem to be small clear
>cuts.

Your criticism of the practice described is probably valid.
However, the practice you are describing is called "high-grading" 
in forestry parlance. The term "selective logging" is frowned upon
by at least some prominant silviculturists.

What people are probably referring to when they use the "S"-word
is "selection cutting" or a "selection system". This process 
entails the precise removal of certain size classes and species
from a stand in order to produce and then maintain a specific
age structure and species composition. 

It poses a number of problems, one of which is that, in the nature
of things, one must cut more small trees than big ones. Who will
buy them? It entails continual entries into the stand, hence
a permanent access network of some kind. It also requires essentially
complete inventory data, down to the individual stem (remember,
the idea is to remove particular trees at intervals).

Nonetheless, such systems have been employed for extended periods
of time in some European forests. The great advantage is that
you can produce a small but constant flow of large high-value trees,
which you will never get sustainably under current practices in BC.

Advocating small clear cuts may be a suitable alernative in 
BC, or for very large forest estates in general, as the inventory 
requirement for (very expensive) inventory data is reduced.
One is still left with the problem of determinng the rotation age,
so that great big trees will continue to come into existance.

>
>2. Preventing forest fires and logging in a forest leads to a buildup
>   of forest trash that can exacerbate the damage when a forest fire
>   eventually burns through an area.
>
>Some forest ecosystems, such as the longleaf pine - wiregrass
>ecosystem of the south-eastern US, are fire adapted and will not be
>sustained if forest fires are prevented (beech-magnolia takes over).
>Are the forests of BC similar? 

Some (perhaps) are. Ponderosa pine / bunchgrass comes to mind.

>I remember reading that the forest
>fires that burned through Yellowstone a few years ago caused so much
>damage because of the trash buildup that resulted from preventing
>natural fires and logging in previous years. 

As far as I know, this issue is not resolved. 
I believe, however, that within limits, weather conditions probably 
overwhelm the effects of small changes in surface fuel loading.
See: 

@InCollection{johnson91,
  author = 	"Edward A. Johnson and Kiyoko Miyanishi",
  title = 	"Fire and Population dynamics of {L}odgepole pine and
{E}nglemann spruce forests in the southern {C}anadian {R}ockies",
  booktitle = 	"Coniferous Forest Ecology from an International Perspective",
  publisher = 	"SPD Academic Publishing bv",
  year = 	"1991",
  editor = 	"N. Nakagoshi and F. B. Golley",
  OPTchapter = 	"",
  OPTpages = 	"",
  address = 	"The Hague",
  OPTmonth = 	"",
  OPTnote = 	""
}
 
for a discussion of fire genesis in a pine/spruce forest which is probably
compareable in some respects to Yellowstone.

>Are forest fires and or
>logging necessary to maintain a stable forest ecosystem in BC? 

I would say that logging is never necessary to maintain stability on
the time frames of interest, unless to compensate for some other
human disruption; fire suppression is often mentioned in this regard,
although I am sceptical.

>Are
>there important differences in management practices of the coastal
>temperate rain forests and the drier interior regions?

Most certainly. Fires, for example, are rare on the coast.
Landslides and wind storms are the predominate disturbance events;
they are infrequent and localised in impact.

Some of the drier interior forests, such as the Sub-Boreal Spruce and
Boreal forests are fire-dominated eco-systems in some respects.
The seminal works on this sort of forests are

J. S. Rowe, 1961 , Can. J. Bot (39) 1007-1017
M. L. Hienselman, 1973, Quaternary Research (3) 329-382

In my opinion, however, the effect of fire on structuring these
ecosystems is not yet fully understood. It is therefor
premature to design (landscape management strategies) which attempt
to mimic natural patterns via timber harvesting methods.

>
>Gerry Neufeld, Brandon University, Brandon, MB, Canada
>
>neufeld at brandonu.ca


--
Steve Cumming			"I could save the world
stevec at geog.ubc.ca		 if I could only get the parts."
			Honi soit qui mal y pense.
							



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