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AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3 reduce risk of attack by beetles. Both also reduce the quality, quantity, and distribution of habitat for species dependant on higher stand densities and canopy closure levels, especially in the short-term. In the long-term, both would result in greater stability and distribution of habitat that is more reflective of the biological capacity of the area with habitats less likely to be disrupted by uncharacteristic events such as uncharacteristic wildfire or insect epidemics. Alternative 2: Fifty-seven (57) percent (6,020 acres) of the moderate or high risk rated acres would remain untreated under Alternative 2. Effects of not treating these stands would be the same as described under Alternative 1. Alternative 3: Fifty-three (53) percent (5,681 acres) of the moderate or high risk rated acres would remain untreated under Alternative 3. Effects of not treating these stands would be the same as described under Alternative 1. The risk of loss of existing thermal cover, particularly optimal thermal cover, is greater under Alternative 3 because no existing optimal thermal cover (stands meeting the LRMP definition of thermal cover with 40 percent or more canopy closure) acres would be thinned to reduce stocking and canopy closure levels and thereby reduce the risk of bark beetle attack. In the event of such an attack, the loss of optimal thermal cover is likely to be much greater and spread across more acres than would occur under Alternative 2, which thins much of the existing optimal thermal cover. Cumulative Effects – There are no identified cumulative or cumulatively significant effects associated with any of the current, on-going, or reasonably foreseeable actions in conjunction with any of the three alternatives in this analysis. None of the other current, on-going or reasonable and foreseeable actions would have any measurable cumulative effects on bark beetle risk in conjunction with any of the three alternatives. None of the activities or actions would result in changes to existing condition (Alternative 1). For Silvicultural/Vegetation Effects (thinning) related to Fire/Fuels (see Key Issue #3 Wildfire Risk below). Key Issue #3 - Wildfire Risk Increasing forest stand and shrub community densities are contributing to an increased risk of high or extreme fire behavior potential due to increases in fuel loadings and the development of ladder fuels. Currently, 34 percent (18,491 acres) of the planning area is classified as either high (3,463 acres/six (6) percent) or extreme (15,028 acres/28 percent) for wildfire behavior potential. Fire exclusion (fire suppression), lack of hazardous fuel treatment, and development of denser forest stands have increased fuel loadings above historic conditions. Fire starts historically in the project area have been lightning and human caused. With the rise in population growth in Central Oregon the risk of fire sta.rts from high public use are predicted to increase. The combination of higher fuel loadings and increased risk of fire starts creates the potential for high intensity, stand replacing fire behavior. Should a fire start, go undetected and a wildfire occur, forest health, wildlife habitat, soils, water quality, recreational values and the safety of public and fire fighters could be significantly affected. • Measurement Standard: Number of acres treated that are rated as moderate to extreme fire behavior potential Existing Conditions The Opine planning area has experienced a number of large fires within the past 60 years. The Deschutes National Forest defines a large fire as one that is 100 acres or greater in size. Since 1945, approximately 6,370 acres (11.7 percent of the planning area) have burned within the planning area with the average fire 3-40
ISSUE 3 – WILDFIRE RISK – Existing Conditions – Fire Behavior Fuel Models CHAPTER 3 size being approximately 579 acres. A total of 23 fires, totaling approximately 29,400 acres have occurred in the planning area since 1911 with eight (8) of those fires, totaling approximately 2,000 acres, having occurred during the past 30 years (Silviculture Report). The large fire activity during this period has occurred predominately in the mid and high elevations of Pine Mountain (Pine Mountain 1968, Pine Mountain 1977, Dead Wilma 1977). Historic Mean Fire Return Intervals ranged from approximately 10 to 100 or more years in high elevation sites to approximately 10 to 75 years in mid-elevation sites. This is in contrast to recent research on Pine Mountain that found the average return interval to be approximately 14.25 years prior to 1870 and that the return interval increased to 43.15 years after 1870. This increase in the return interval has been attributed to fire suppression activities initiated in the early 1900s (Fire/Fuels and Air Quality Report). Initiation of fire suppression in the early 20 th century allowed for naturally occurring fuels to increase in lower and mid elevation areas to levels above those found historically. Ladder fuels – shrubs, low branches, and small diameter trees – have increase in both numbers and distribution. Horizontal fuels are more continuous and trees have increased in both height and density. On Pine Mountain, the majority of the pine stands contain large diameter trees with a dense understory of sapling, pole size or “blackbark” trees. In the Tepee Draw area, much of the area is open with clumps of trees dominated by large ponderosa pines. Large contiguous areas of dense, highly flammable shrubs such as bitterbrush and sagebrush have developed here. These shrub areas have potential for flame lengths of up to 20 to 30 feet as observed on the Skeleton fire (1996), increasing the potential of crowning, spotting and major fire runs. These conditions do not permit fires to burn with the lower intensities common to earlier fire events, but rather they burn with higher intensities resulting in the increased mortality in both forested and xeric shrub communities. A similar condition has also occurred in upper elevation sites with similar results. Lightning is the leading cause of fires in the planning area. Since 1992, there have been 45 known fire occurrences of which 31 (69 percent) were the result of lightning strikes. Typically, lightning storms track from the south and southwest in contrast to the prevailing winds which typically track from the west and northwest during the period of April through September. Of the 45 known fires since 1992, 14 (31 percent) were human caused. This number is projected to increase. Roads 18, 23, 25, 2510 and 2017 experience increasing levels of use during summer and fall. Other primary and secondary roads within the planning area are also experiencing increasing use. There are numerous dispersed campsites which have been active over the years. These areas were historically utilized by hunters but increasingly are utilized by dispersed campers including OHV enthusiasts. In ponderosa pine stands, underburning is the only economical method at this time to remove the needles, limb case and bark slough that accumulates at the base of the trees. Most areas within the planning area have roads that provide access for fire suppression activity. Fuel conditions adjacent to most roads, including major access routes such as Roads 18, 2017, 23, 25, and 2510; do not provide defensible space for suppression forces during high intensity wildfire events. Primary and secondary roads do not provide safe escape routes for either suppression forces or the public. Desired Condition - From a fuels management perspective, the landscape within the planning area should display a mosaic of strategically placed areas that are managed to achieve the following goals: reduce fire behavior potential; aide in the suppression of wildland fire (i.e. defensible space); and provide protection to valuable resources and especially improvements located on Pine Mountain and at Sand Springs (Fire/Fuels and Air Quality Report). 3-41
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United States Department of Agricul
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Abstract: The Opine Planning Area i
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PROJECT LOCATION CHAPTER 1 Figure 1
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PURPOSE AND NEED CHAPTER 1 commerci
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PLANNING DIRECTION - MANAGEMENT ALL
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PLANNING DIRECTION - MANAGEMENT ALL
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OTHER PLANNING DIRECTION & STRATEGI
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OTHER PLANNING DIRECTION & STRATEGI
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ANALYSIS ISSUES CHAPTER 1 The Opine
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ANALYSIS ISSUES CHAPTER 1 overstock
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ANALYSIS ISSUES CHAPTER 1 Soils The
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ALTERNATIVE DESCRIPTIONS CHAPTER 2
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ALTERNATIVE DESCRIPTION - ALTERNATI
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COMPARISON OF ALTERNATIVES CHAPTER
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COMPARISON OF ALTERNATIVES CHAPTER
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IMPLEMENTATION GUIDELINES CHAPTER 2
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IMPLEMENTATION GUIDELINES CHAPTER 2
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AFFECTED ENVIRONMENT & ENVIRONMENTA
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AGENCIES AND PUBLICS CONSULTED CHAP
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Environmental Assessment

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