From the Ashes

dwheeler at dwheeler at
Fri Jan 19 02:28:08 EST 2001

In article <942oo9$d99 at>,
  lewitt at (Martin E. Lewitt) wrote:
> In article <3A64D64D.D11244D2 at>,
> Karl Davies  <karl at> wrote:
> >Passing this on from Taxpayers for Common Sense:
> >
> >As you may know, the 2000 fire season was the most expensive fire season
> >in decades. The federal government spent a record $1.6 billion fighting
> >the most severe wildfires our nation has ever seen:
> >
> >
> >From the Ashes: Reducing the Harmful Effects and Rising Costs of Western
> >Wildfires, a new report by Taxpayers for Common Sense, finds that
> >federal mismanagement of National Forests was largely responsible for
> >the enormous costs of managing these fires. The report details policy
> >recommendations for the new Congress and the new Administration that
> >could increase the effectiveness of firefighting while reducing wasteful
> >spending. Please take a few moments to view the report. It's available
> >online in HTML and PDF formats at
> > .
> One claim concerned me:
>    Most importantly, unless thinning activities are accompanied by
>    proper disposal of slash, thinning activities can actually result in
>    increased fire risk.
> This comment was based on this reference:
>    Russell Grahamet al., 1999, The Effects of Thinning and Similar
>    Stand Treatments in Western Forests, Gen. Tech. Rep. PNW-GTR-463,
>    (Portland, OR: USDA, Forest Service), 15.
> I left my "slash" on my property, pretty much where it lay.  I thought
> the idea was to eliminate pathways to my house and to crowns of the
> large fire resistant trees.  I figured the slash would eventually
> decompose returning nutrients to the soil, and also would suppress
> the grown of more fuel on the ground underneath it.  I did worry that
> the fuel it represents might result in high flames, but assumed they
> would not be high enough to span the distance I had created.
> Has there been any tradeoff analysis of these kinds of issues?
>                            -- thanx, Martin
It kind of depends on the actual fire situation you encounter, Martin.
Most firest in the west are not "devastation" fires, which kill
everything in their pathway, sterilize soil to a depth of 2 feet, and
destroy most larger woody debris.

Less severe fires remove any detritus on the ground, and _may_ kill some
trees, depending on the buildup of dry biomass near them, which can then
slowly eat through the bark layer.

Finally, there are the controlled burns which are designed to simply
reduce the small woody debris build-up, which can kill some of the more
dense younger tree stands in some conditions (like true fir stands in
Ponderosa pine forests) or brush as understory.

Raking or chipping debris into 3-4 inch layers in bands underneath the
understory may cause hotter fires locally, but also can be used to
eliminate lower branches which can act as stepping stones to the live
canopy. Ironically, these bands of chipped debris degrades more rapidly
than larger woody debris just left lying on the ground. Degradation is a
function of exposed biomass and proximity to the ground. Large woody
debris takes several years to decades or even centuries to degrade in
nature. But as they degrade, the act as water reservoirs during dry
periods, transferring the water accumulated by the degradation process to
the living trees nearby. Mycorrhizal fungi also are transferring the
nurtrients released from within the cells of the wood back to the growing
trees nearby, along with accumulating as much was as they can. This is
important, as the fungi can absorb moisture from such a small thing as a
temperature difference between the soil surface and the cooler soil an
inch or two deeper.

As wood degrades, it _adsorbs_ water and nutrients, becomes richer in
nitrogen and phosphorus from insect and animal droppings, and becomes
even more important to the surrounding forest as a water source.

Daniel B. Wheeler

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