Final Environmental Impact Statement Helena National Forest Weed Treatment Project United States Department of Agriculture Forest Service Helena National Forest
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FINAL ENVIRONMENTAL IMPACT STATEMENT HELENA NATIONAL FOREST WEED TREATMENT PROJECT UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE HELENA NATIONAL FOREST Lewis and Clark, Powell, Jefferson, Broadwater, and Meagher Counties May, 2006 Responsible Official Kevin T. Riordan Forest Supervisor Helena National Forest For Further Information, Contact: Jay Winfield Helena National Forest 2880 Skyway Drive Helena, MT 59601 ABSTRACT The Helena National Forest is proposing to treat weeds using Integrated Pest Management (IPM) on approximately 23,000 acres of National Forest System lands over the next 12 years. The Proposed Action is considered as Alternative A. Treatment methods would be largely through aerial and ground application of herbicides, with mechanical and biological control where appropriate. Environmental protection measures would be included to protect sensitive resources (e.g., water quality, fish habitat, vegetation, human health, and cultural resources). Two other alternatives were considered in detail in the Environmental Impact Statement. One is Alternative B, which includes fewer treatment acres and no aerial application of herbicides. Alternative C is the No Action Alternative, which continues the current weed treatment program, including some herbicide treatments. Final EIS Summary S-1 SUMMARY INTRODUCTION weeds will continue to increase if action is not taken to control their spread. Noxious weeds can This Environmental Impact Statement (EIS) crowd out native plants and diminish the discloses potential effects of implementing a productivity, bio-diversity, and appearance of land. noxious weed treatment project and alternatives Although only a small portion (approximately on the Helena National Forest (Helena NF). 23,000 acres) of the Helena NF is now infested Currently, about 22,668 acres of the Helena NF with weeds, results of uncontrolled weed spread and 198 miles of roads are infested with noxious are well documented (Sheley et al. 1999). weeds. The main weed species of concern are Infested acres continue to increase because all spotted and diffuse knapweed, leafy spurge, identified infestations cannot be effectively treated Dalmatian and common (or yellow) toadflax, ox- under the existing program. eye daisy, and sulfur cinquefoil. Other weed species of concern include Russian knapweed, Ongoing inventory and monitoring shows that Canada and musk thistles, St. Johnswort, and there is a need to: houndstongue. The rate of spread of these weeds is expected to expand 14 percent per year (Asher Control Noxious Weeds 1998) and may increase due to large wildfires ¾ New weed species are coming into the (recent and future). A shift from trees, shrubs, Helena area from all directions with and bunchgrass vegetation to noxious weeds will potential for new weed species to move in cause a decrease in wildlife forage, a reduction in and spread. Adjacent states and other areas species diversity, and an increase in soil erosion in Montana already have infestations of and overland flow due to a decrease in surface weeds that have not yet arrived on the cover. An estimated 338,600 acres of the Helena Helena NF. New invaders need to be NF are currently susceptible to weed invasion treated aggressively to limit establishment of based on acres of rangeland and forested areas new weed populations. with less than 35 percent tree canopy coverage, including 78,000 acres burned in 2000 and 2003. Treat Weeds on Rangeland Future activities or events that reduce canopy cover could increase the acres susceptible to ¾ A healthy rangeland provides high quality weed invasion. forage for native herbivores and domestic livestock as well as providing cover and PROJECT AREA foraging habitat for many small animals and birds. Establishment of weeds reduces The Helena NF encompasses approximately forage production, which can result in 975,000 acres in central Montana within Lewis and reduced wildlife numbers (Duncan 1997). Clark, Powell, Jefferson, Broadwater, and Meagher Rangeland with a good cover of native Counties. The project area consists of land within vegetation holds the soil, reducing erosion the boundaries of the Helena NF. Proposed from runoff. Soil erosion from a weed- treatments would occur throughout the Forest, dominated site may contribute sediment to on National Forest System lands. waterways (Lacey et al. 1989), which can decrease productivity of a stream by PURPOSE AND NEED FOR reducing availability of aquatic habitats. ACTION Treat Weeds in Burned Areas Damage from noxious weeds is increasing due to ¾ Two large wildfires on the Helena NF in their expanding populations and distribution of 2000 and one in 2003 burned about 78,000 Final EIS S-2 acres including both rangeland and timber. from initial application. Maintenance treatments Additional large fires are expected to occur may be ground based, but in some cases, a second in the future. Other previous fire areas such or third aerial treatment may be required. as the Scapegoat fire (1988), Warm Springs fire (1988), and the North Hills Fire (1984) HERBICIDES have experienced weed spread. Chemical treatments would include both ground Susceptibility of burned areas to new weed and aerial herbicide applications. Chemical invasion is increased due to decreased applications would take place at the appropriate canopy cover and increased bare ground time of year for targeted weed species and (Goodwin and Sheley 2001). Nearby weed environmental considerations such as proximity to infestations are poised to invade burned water or residential areas. Equipment such as areas if management measures are not taken. helicopters, trucks, all-terrain vehicles (ATVs), Treat Weeds in Remote Areas horse, and backpack sprayers would be used. New herbicides are being developed which are ¾ Large weed infestations continue to expand more species specific and less persistent or less on the Helena NF because of arduous access mobile in soil. Newly registered water-soluble for equipment and personnel, creating herbicides displaying toxicity, leaching, and difficult and sometimes unsafe working persistence characteristics less than or equal to conditions. As a result, about 6,800 acres of picloram may be used. the total infested acres are not currently being treated. Weed infestations have Ground applied herbicide treatments are doubled and in some cases tripled in proposed in Scapegoat and Gates of the inaccessible areas over the last decade; while Mountains Wilderness areas. weed populations in accessible areas, such as Surfactant adjuvant would be used in certain roads, have shown decreases due to situations to increase efficacy, primarily on target consistent treatment measures. Cost- species with a waxy cuticle (especially toadflax), or effective and safe methods are needed to when temperature and humidity are not optimal control spread of weeds in these areas. (but still within label and more restrictive locally prescribed limits) yet other conditions (such as PROPOSED ACTION plant phenology) are ideal. Surfactants may be used during periods of drought. Surfactants used The Helena NF proposes to implement an would be a silicone-blend type, (including silicone aggressive noxious weed control program, which components mixed with non-silicone components includes aerial application of water-soluble such as modified seed oils) such as Phase II®, herbicides, increased ground application of water- added to tank mixes. Surfactant adjuvant would soluble herbicides, and increasing biological and be used in accordance with label requirements for mechanical control efforts through use of insects both the herbicide and the surfactant products. and grazing. All of these methods would become part of the Helena NF’s integrated weed BIOLOGICAL CONTROLS management program. Esther/fat-soluble herbicides will not be used. Biological controls (such as insects) would continue to be introduced where appropriate and The project would be implemented over a 12-year newly approved agents would be considered for period. Not all acres would be treated in the first use. year, but some areas would be treated repeatedly on a 2 or 3-year rotation to ensure effective GRAZING control, as part of a “maintenance mode of action.” Follow-up maintenance treatments are Grazing of livestock such as sheep or goats would expected to require reduced amounts of herbicide occur to control leafy spurge, Dalmatian toadflax Helena National Forest Weed Treatment Project Summary S-3 and spotted knapweed. Grazing would be done number of acres treated would change with the on a contract basis, would be high-intensity and Adaptive Management Strategy. For each short duration, and would be done with animals resource, an analysis area was determined that specially conditioned to graze on target weeds. could be used to adequately measure cumulative effects of the proposed alternatives. Unless MECHANICAL TREATMENT otherwise stated, the cumulative effects area is the treatment area. Mechanical treatment such as hand pulling or grubbing would occur on sensitive areas or in very Temporal Scope small infestations. Cultivation and/or seeding would occur where natural recovery of native The timeframe for project implementation is 12 species is inadequate to provide needed years. Direct, indirect, and cumulative effects, if competition to prevent reinvasion by weeds. any, would occur during that period. For cumulative effects analysis, an additional 10 years ADAPTIVE MANAGEMENT past the final implementation year is considered, unless otherwise described