Environmental Assessment

AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3
Alternatives 2 and 3 - The measure for CWM and surface organic matter was evaluated qualitatively
based on the probable success of implementing appropriate BMPs and recommended guidelines that
address adequate retention of these important landscape components to meet soil productivity and wildlife
habitat objectives (see Wildlife Section and Chapter 2 Mitigation). A minimum amount of 5 to 10 tons
per acre of CWD on ponderosa pine sites and 10 to 15 tons per acres on mixed conifer or lodgepole pine
sites is recommend to ensure desirable biological benefits for maintaining soil productivity without
creating an unacceptable fire hazard (Brown et al., 2003 Graham et al ., 1994). Based on guidelines for
estimating tons per acres of CWD (Brown 1974, and Maxwell, Ward, 1980), the levels of CWD retention
to meet wildlife habitat objectives (Eastside Screen direction) would also meet these soil resource
objectives (Soils Report, page 31).
The proposed harvest activities under both alternatives would reduce potential sources of future CWM,
especially where mechanized whole-tree yarding is used in activity areas. Harvest activities also recruit
CWM to the forest floor through breakage of limbs and tops during felling and skidding operations.
Existing down woody material, other than lodgepole pine, would be protected from disturbance and
retained on site to the extent possible. Understory trees, damaged during harvest operations, would also
contribute woody materials that provide ground cover protection and a source of nutrients on treated sites.
It is expected that enough broken branches, unusable small-diameter trees, and other woody materials
would likely be available after mechanical thinning activities to meet recommended guidelines for CWM
retention. Long-term, scattered blow down, broken tops and other natural processes are expected to add
to existing amounts of CWM (Fire/Fuels and Air Quality Report). Alternative 3, because it treats more
acres and therefore removes more potential mortality, would result in a greater reduction in potential
future CWM (long-term) than would Alternative 2. Conversely, Alternative 3 also would potentially
provide more debris, damaged trees, unusable material, and related materials than would Alternative 2
(short-term).
Fuel reduction treatments would also reduce CWM and some of the forest litter by burning logging slash
and natural fuel accumulations. Logging slash generated from commercial harvest that is in excess of
requirements for wildlife and soils, would be machine piled and burned on log landings and/or main skid
trails. Post-harvest review by fuel specialists would determine the need for prescribed underburn
treatments, especially where fine fuel accumlations increase the risk of wildfire to unacceptable levels. If
prescribed fire is recommended, burning would occur during moist conditions to help ensure adequate
retention of CWM and surface organic matter following treatment. Fuel reductions achieved through
planned ignitions usually burn with low-to-moderate intensities that increase nutrient availability in
burned areas. Low intensity fire does not easily consume material much larger than 3 inches in diameter,
and charring does not substantially interfere with the decomposition or function of coarse woody debris
(Graham et al., 1994). Although proposed prescribe burning is not intended to intentionally kill residual
trees, tree mortality in varying amounts and in various tree sizes will occur during the implementation of
burning. Research on light to moderate intensity and severity underburns show that approximately a six
(6) percent mortality in trees less than two (2) inches DBH (Fire/Fuels and Air Quality Report). Any
dead trees killed from prescribed burn treatments will eventually fall to the ground and become additional
sources of CWM. Depending on the rate of decay and local wind conditions, many of the small-diameter
trees (less than 10 inches) would be expected to fall within the short-term (less than 5 years). Alternative
2, because it has more acres of fuel reduction treatments and many acres overlap vegetation (timber
harvest) treatments, has the greater potential to result in a greater short-term reduction in both CWM and
surface organic matter than does Alternative 3. Long-term, greater than five (5) years, there is likely to be
no measurable difference in the quantity or distribution of CWM associated with fuel treatments under
either alternative. Very long-term (10 years and longer), because Alternative 3 thins more acres than
Alternative 2, there will likely be greater potential numbers of larger diameter CWM much sooner under
Alternative 3 than Alternative 2 due to increased growth rates on residual trees.
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