Environmental Assessment

AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3
In conclusion, there is no definitive, quantifiable effect on deer numbers due to cumulative effects.
There is, given the evidence presented, a certainty that the sum of effects have contributed to reduced
deer numbers. A variety of other variables may also be contributing to low deer numbers, e.g. weather,
snow conditions, predators, poaching, road/trail disturbance, disease, etc. Adjacent private lands are
being developed and eliminating historic deer wintering habitat, which may be one of the more
important impacts on local deer herds. In the long-term, with forest re-growth, travel management, and
reduced wildfires, the deer herd numbers will rebound. Additionally, the effects of past wildfires on
deer winter ranges have had the most substantial, long-term negative impacts on deer habitats. The
assessed management activities are designed to reduce the risk of future catastrophic wildfires, and
subsequently impacts to deer. Therefore, the negative cumulative effects described for management
actions are short to mid-term and will be a benefit to deer both in the short (reduced fires) and longterm
(>20 years, more cover).
Measurement Standard - Thermal Cover
Thermal cover is only required in the Deer Habitat allocation (i.e. winter range) and the objectives is 30
percent. There is no exception for black-bark pine stands.
Thermal Cover – As noted previously, thermal cover within the planning area is currently below the
MA-7 LRMP objective of 30 percent. Across the winter range habitat units (WRHUs), thermal cover
percentages range from an average of two (2) to approximately 20 percent with an average of about
eight (8) percent. Only six (6) percent, or 1,338 acres, is actually located within the MA-7 allocation
Thermal cover increases to nine (9) percent across the entire planning area, including both forested and
non-forested acres.
It is unlikely that many of the forested areas in the planning area are biologically capable of sustaining
thermal cover objectives specified in the LRMP for the deer winter range land allocation (MA-7). The
silviculture report cites a 1978 paper by Barrett, which concluded that ponderosa pine stands with site
indices of less than 90 are not capable of providing dispersal habitat on a sustained basis. Thermal
cover habitat was defined (Barrett, 1978) as stands with an average diameter of six (6) inches dbh and a
canopy closure of at least 25 percent. Site indices across most the planning area is below 90. The
research also suggests that stands seven (7) inches dbh or smaller might meet thermal cover, but only at
the high end of the upper management zone. Stands above seven (7) inches dbh can only meet the 40
percent canopy closure if managed above the upper management zone and at stocking levels so high
that beetle outbreaks are likely (Silviculture Report, Appendix D Silvicultural Specialist Letters, page
53).
Alternative 1 (Thermal Cover): There would be no substantial short-term change (less than 10 years)
in the acreage or percent of thermal cover in the planning area. Under Alternative 1, the number of
acres rated as either marginal or acceptable thermal cover would be expected to increase in the shortterm
assuming no disturbance from wildfire, insects, or disease. The quantity, quality, and distribution
of thermal cover may increase during this time period due to increasing stand densities. These same
acres are also rated as moderate to high risk for bark beetle attack. Fuel loadings would continue to
increase resulting in an increased risk and potential for a high intensity wildfire that would likely result
in the loss of both tree and shrub vegetation over very large areas. Such losses would eliminate existing
thermal cover as well as hiding cover and bitterbrush browse for mule deer.
Long-term, more than 10 years and assuming no disturbance events such as bark beetle attack or a
wildfire, the quantity, quality, and distribution thermal cover could be expected to increase due to
continuing increases in stand densities. Increasing stand densities would result in an increasing risk to
insect and/or disease outbreak, especially in densely stocked ponderosa pine stands, and a high risk of
wildfire. Both events, either singly or in combination, would result in significant reductions if not the
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