Hemlock Landscape Restoration: Noxious Weeds Assessment. Eric Vane Forester, Calaveras Ranger District

Transcription

1 : Noxious Weeds Assessment Prepared By: Eric Vane Forester, Calaveras Ranger District Date:

2 NOXIOUS WEED RISK ASSESSMENT HEMLOCK LANDSCAPE RESTORATION STANISLAUS NATIONAL FOREST CALAVERAS RANGER DISTRICT Prepared by Eric Vane Introduction Forest Service Manual 2903(4) requires the Forest to determine the risk of introducing, establishing, or spreading invasive species associated with any proposed action, as an integral component of project planning and analysis, and where necessary provide for alternatives or mitigation measures to reduce or eliminate that risk prior to project approval. The Land and Resource Management Plan (Forest Plan) as amended, and the Pacific Southwest Region Noxious Weed Management Strategy require that a noxious weed risk assessment be conducted to determine risks for weed spread associated with different types of proposed management activities (USDA, USFS 2010). Noxious weeds are defined in FSM 2905 and the Plant Protection Act of 2000 as any plant or plant product that can directly or indirectly injure or cause damage to crops (including nursery stock or plant products), livestock, poultry, or other interests of agriculture, irrigation, navigation, the natural resources of the United States, the public health, or the environment. The California Department of Food and Agriculture (CDFA) developed and maintains the State noxious weed list which the referenced in developing the Noxious Weeds and Nonnative Invasive Pest Plants of Concern for the Forest. The weed ratings assigned by CDFA reflect CDFA's view of the statewide importance of the pest, the likelihood that eradication or control efforts would be successful, and the present distribution of the pest within the state (CDFA [n.d.]b). CDFA defines their noxious weed ratings as follows: A - A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.... A-rated pests are subject to state (or [County Agricultural] commissioner when acting as a state agent) enforced action involving eradication, quarantine regulation, containment, rejection, or other holding action. B - An pest of known economic or environmental detriment and, if present in California, it is of limited distribution.... At the discretion of the individual county agricultural commissioner they are subject to eradication, containment, suppression, control, or other holding action. C - A pest of known economic or environmental detriment and, if present in California, it is usually widespread. If found in the state, they are subject to regulations designed to retard spread or to suppress at the discretion of the individual county agricultural commissioner. Inventories for weeds in support of Forest Service projects are conducted using the Noxious Weeds and Non-native Invasive Pest Plants of Concern for the Forest list as a guide. The list was generated from several sources including the Forest Plan (Table 3.6a, 2001 SNFPA Final Environmental Impact Statement (FEIS), V.2, Chpt 3, part 3.6, pages ), the CDFA list of State-rated noxious weeds (CDFA [n.d.]a), new weed discoveries in the Forest, information provided by local County Agricultural 1 P a g e

3 Commissioners, occurrence records at CalFlora (a web-based botanical database), published technical references (Baldwin, et. al. 2012, Bossard, et.al. 2000, Whitson, et.al. 1996), and personal observations. This noxious weed risk assessment evaluates the risk for weed introduction and spread by project activities in the project. Project Area The project is located on the Calaveras Ranger District of the Stanislaus National Forest in Calaveras County, California (Figure 1). The project area is northeast of Arnold and southwest of the Bear Valley Recreation area on the north side of the North Fork Stanislaus River. The project area would be in all, or portions of, Township 6N, Range 16E, Sections 1-5, 8-12, Township 6N, Range 17E, Sections 5 and 6, Township 7N, Range 16E, Sections 12 14, 23 27, 33 36, and Township 7, Range 17E, Sections 15 22, and contained within the Tamarack and Calaveras Dome USGS 7.5 minute Quadrangle Maps. Elevations within the 13,400 acre project area range between 5,400 feet and 7,920 feet. Purpose and Need The purpose of the Project is to improve the ecological resilience of the landscape. The Project focuses on reestablishing the Forest s species composition, structure, and pattern on the landscape, and ecological processes (e.g. hydrologic function, fire regime) necessary to facilitate terrestrial and aquatic ecosystem sustainability, resilience, and health under current and future conditions. An ecologically sustainable and resilient landscape would have a greater capacity to adapt and thrive in the face of natural disturbances and large scale threats, such as; fire, drought, and insect and disease infestations which may be exacerbated by current and future changes in climate. The Forest Plan Direction (USDA 2010) presents the current Forest Plan management direction, based on the original Forest Plan as amended. The Forest Plan Direction includes forest wide standards and guidelines (p ) and applicable management area direction for General Forest (p ) and Wildlife (p ), Developed Recreation or Administration Site (p ), Near Natural (p ), and Scenic Corridor (Retention and Partial Retention) (p ). Sierra Nevada Framework Land Allocations as defined in the Forest Plan occurring in the project area include: General Forest, Old Forest Emphasis Areas, California Spotted Owl Protected Activity Centers (PAC), Northern Goshawk PAC, California Spotted Owl Home Range Core Areas (HRCA), Wildland Urban Intermix (WUI): Defense and Threat Zones, and Riparian Conservation Areas (RCA). The Forest Plan Direction includes desired conditions, management intents, and management objectives for each land allocation (p ). Survey and Existing Noxious Weeds From 2013 to 2014 botany surveys were conducted to determine the presence of sensitive and rare species. Crews were instructed to note and GPS any areas where noxious weeds were present. An existing populations of Klamath weed (Hypericum perforatum L.) was monitored and a new infestation of spotted knapweed (Centaurea stoebe ssp. Micranthos) was found. Klamath weed is a California Department of Food and Agriculture (CDFA) Class C noxious weed, and spotted knapweed is a CDFA Class A weed. The spotted knapweed population was located on the western side of the project area and was hand pulled and bagged. The Klamath weed population is larger occupying a ten acre 2 P a g e

4 portion at the southern end of the project area near Gann s Quarry. The population is intersected by Forest Service Road 6N58Y and has been hand pulled in the past, however, due to the extent of the infestation it has not been eradicated from the area. Factors Independent of Proposed Action The Ramsey fire in 2012 burned about 401 acres in the Hemlock project area including part of the area which is infested with Klamath weed. This disturbance creates advantageous conditions for noxious species to establish and spread more readily due to the open conditions. Numerous roads and motorized trails are present in the Hemlock project area which may function as a pathway for the dispersal of noxious propagules. Forest users have the ability to spread noxious plant propagules on vehicles, clothing, and shoes which they pick up from either outside the forest or transport within the forest. Hemlock is a popular area for off highway vehicle (OHV) use, and hunting which results in a higher risk of noxious plant establishment and spread. Prior timber related activities in the project area include plantations which have been clear cut, planted, and thinned over the previous century. Activities associated with timber actions can create advantageous conditions for the establishment and spread of noxious species by creating open, disturbed conditions, and as a pathway for propagules which may be on transported into the project area on machinery. Prescribed fire and fuels reduction treatments have been conducted throughout the project area. Prescribed fire and fuels treatments can create openings where noxious weeds can establish and spread. Some noxious species, including the Kalmath weed, have enhanced germination due to brief exposure to heat (Crompton et al. 1988). Alternative 2 (No Action) Indirect, and Cumulative Effects Known populations of noxious weeds in the project area may receive ongoing hand pulling, but populations would not spread, and habitat would not be enhanced through project activities. The population of Klamath weed which is present around road 6N58Y may spread as a result of forest users who inadvertently transport Klamath weed propagule on their vehicles. Alternative 1 (Proposed Action) Under Alternative 1 (proposed action) a variety of treatments will be implemented to meet the Hemlock project purpose and needs including: Forest restoration treatments: Mechanical thinning which will reduce the canopy cover (CC) across 3925 acres of the project area. No trees over 30 inches diameter at breast height (DBH) will be harvested, and CC will not be reduced by more than 30 % in any stand. Gaps of up to 1.5 acres will be created in order to mimic historic vegetation patterns. Scenic corridor treatments: Mechanical thinning which will reduce residual CC to 40% along the highway 4 corridor across 421 acres. Understory treatments include reductions to the understory biomass (trees 4-10 inches DBH and shrubs). 3 P a g e

5 Fuels reduction treatments: Includes a variety of hand thinning, mastication, and pile burning activities across 967 acres and prescribed fire on 4965 acres of the Hemlock project area. Prescribed fire will be a combination of understory burns and pile and burn activities. Mature forest wildlife habitat restoration: Includes hand thinning treatments of trees under 6 inch DBH and 10 inch DBH depending on location and comprises 2301 acres of the Hemlock project area. Hand thinning treatments are followed by pile and burn operations to remove fuels. Recreation: Actions include the enhancement of a highly used dispersed campground to concentrate use, the creation of 1 mile of new OHV trails, decommissioning a total of 1.1 miles of user created OHV trails, and the creation and improvement of non-motorized trails. Transportation: Actions include 67 miles of road maintenance, 34 miles of road reconstruction, decommissioning of 11 miles. Other transportation activities include gate maintenance, road realignment, gate reconstruction, roadside barriers, temporary roads creation, and watershed rehabilitation. Direct and Indirect Effects Forest Restoration Treatments will create the opportunity for establishment of noxious species and their spread. Mechanical equipment used to conduct treatments may harbor hitchhikers (propagules from previous work sites). In addition, thinning activities which create gaps, open up the canopy, and create disturbance on the ground which may create opportunities for establishment and expansion of noxious species. Over the short term noxious weeds which become established may spread and occupy more space in the Hemlock project area resulting in negative impacts to native species. Scenic Corridor Mechanical thinning in the scenic corridor may result in the introduction and spread of noxious species. Hitchhikers may be transported on machinery used for overstory thinning and mastication of the understory. Openings created by mechanical treatments, and disturbance to the soils will result in advantageous conditions for noxious weeds to become established. Due to its proximity to highway 4 there is a greater chance that noxious propagules are already present in the soil because of the significant amount of traffic along this corridor. Propagules which are already present in the soil may germinate following thinning treatments. Over the short term noxious weeds which become established may spread and occupy more space in the Hemlock project area. Fuels Reduction These activities could create opportunities for propagules to become established because of disturbance to the soil and open conditions resulting from treatments. Heat from the prescribed fire may enhance germination of some noxious species as well. Over the short term noxious weeds which become established may spread and occupy more space in the Hemlock project area resulting in negative impacts to native species. Mature Forest Wildlife Habitat Restoration 4 P a g e

6 There is some opportunity for noxious weeds to become established due to possible import of propagules on the clothing and boots of workers, and on the vehicles they use. However, due to the relatively low impact of hand tools and understory treatments on conditions, these actions will not result in conditions that are as open or disturbed as fuels reduction, scenic corridor, or forest restoration treatments. Over the short term, these treatments should have little impact on the establishment and spread of noxious species. Recreation There is some opportunity for noxious weeds to be introduced as a result of management activities associated with recreation projects. Management activities associated with decommissioning trails, creation of trails and campground improvement can promote establishment and spread of noxious weeds via introduction of propagules on machinery, and due to resulting disturbance from activities. Improvements to dispersed campgrounds, the creation of additional OHV trails, and hiking trails with improved signage could result in increased use of the area by forest users. These users may introduce noxious species which can hitchhike on their vehicles, clothes, or boots resulting in noxious weed establishment. Transportation Management activities associated with transportation actions may introduce noxious plant propagules on machinery used for construction. Improvement to roads may encourage additional use by the public which would increase the risk of noxious plant introduction and spread because of the greater number of forest users. A portion of forest road 6N58Y proposed of decommissioning coincides with a known Klamath weed population. Activities associated with decommissioning the existing road may have an impact on the Klamath weed population due to disturbance and machinery which will be used. Machinery operating in areas known to have Klamath weed may spread propagules by movement of seeds which become attached to the machinery. In addition, disturbing ground near this known population may create opportunities for the Klamath weed to spread into these areas. Heritage Resources; Aquatic Organism Passage Restoration; Streams, Riparian Areas and Special Aquatic Features There will be little or no noticeable impact on the ability of noxious weeds to become established or spread as a result of management activities associated with: heritage resources, aquatic organism passage restoration, streams, riparian areas, and special aquatic features. Cumulative Effects Activities associated with the Hemlock project may result in the opportunity for establishment and spread of noxious weeds. Propagules could spread on machinery which may transport noxious seeds across the project area. Ground disturbance created by these activities may also allow for the establishment and spread of these populations by creating favorable conditions for their growth, and provide additional pathways and vectors. Over the coming decades, noxious weeds which may establish due to these activities could persist in the ecosystem and colonize other parts of the Hemlock project area creating unfavorable conditions for native plant species. Improvements to the transportation system and recreation infrastructure may encourage additional, increased use of the area by the public resulting in increased vectors and pathways for noxious 5 P a g e

7 weeds to be introduced, and spread through the Hemlock project area. Overall there will be a short and long term increase in the risk associated with noxious plant establishment and spread. Alternative 3 Under Alternative 3 a variety of treatments will be implemented to meet the Hemlock project purpose and needs. Treatments will predominantly remain the same as Alternative 1, however, some of the acreages of forest restoration, fuels, and mature forest wildlife restoration treatments will change. Management actions and methods used to implement these actions will not be altered between Alternative 3 the Alternative 1. Direct and Indirect Effects Forest Restoration The effects of forest restoration treatments on noxious weed establishment and spread are unchanged between Alternative 3 and Alternative 1. Scenic Corridor The effects of mechanical management activities on scenic corridor treatments on noxious weed establishment and spread are unchanged between Alternative 3 and the Alternative 1. However, under alternative 3 the scenic corridor will receive an understory burn following mechanical treatment. Fire may result in increased opportunity for noxious weed establishment and spread due to the resulting open conditions and soil disturbance Fuels Reduction The effects of fuels reduction treatments on noxious weed establishment and spread are unchanged between Alternative 3 and Alternative 1. Mature Forest Wildlife Habitat Restoration The effects of mature forest wildlife habitat restoration treatments on noxious weed establishment and spread are unchanged between Alternative 3 and Alternative 1. Recreation The effects of recreation management actions on noxious weed establishment and spread are unchanged between Alternative 3 and Alternative 1. Transportation The effects of transportation management actions on noxious weed establishment and spread are unchanged between Alternative 3 and Alternative 1. Heritage Resources; Aquatic Organism Passage Restoration; Streams, Riparian Areas and Special Aquatic Features 6 P a g e

8 There will be little or no noticeable impact on the ability of noxious weeds to become established or spread as a result of management activities associated with: heritage resources, aquatic organism passage restoration, streams, riparian areas, and special aquatic features. Cumulative Effects The cumulative effects of management actions on the establishment and spread of noxious weeds are unchanged between Alternative 3 and Alternative 1. Mitigation The following management requirements would reduce the likelihood of introducing new infestations of noxious weeds into the project area, and are common between action alternatives. 1) Standard contract provisions for equipment cleaning will be applied to timber and construction activities, including washing of vehicle prior to their arrival at the work site and following completion of work in an area. For all other activities, all equipment that leaves roads or works with soil must be free of soil, mud (wet or dried), seeds, vegetative matter or other debris that could contain seeds. Dust or very light dirt that would not contain weed seed is not a concern. This would prevent new infestations of noxious weeds in the project area 2) During the reroute of Forest road 6N58Y ensure that all equipment is thoroughly washed to remove Klamath weed propagules after use. Continue hand pulling efforts after reroute is complete to reduce the negative impact of Klamath weed on native species. 3) Post signage to educate the public on the risk of noxious weed spread at trailheads and campgrounds to encourage behaviors that will reduce the risk of spread. Alternative Analysis There would be little to no difference between the impact of Alternative 1 and Alternative 3 on noxious weeds in the Hemlock projects area. Actions and acreages do not substantially change between these alternatives resulting in similar outcomes. Noxious Weed Assessment Overall Risk With Management Requirements Implementing the management requirements listed above reduces or eliminates the risks of introducing or spreading noxious weeds in the project area. Implementation of the proposed project with the noxious weed management requirements would impart a low risk of noxious weed introduction and spread by the project. Overall Risk Without Management Requirements Implementing the Project without requiring the management requirements listed above would impart a moderate to high risk of introducing new infestations of noxious weeds or spreading existing weeds. 7 P a g e

9 Literature Cited Crompton, C. W., I. V. Hall, K. I. N. Jensen, and P. D. Hildebrand. "The biology of Canadian weeds. 83. Hypericum perforatum L." Canadian journal of plant science 68, no. 1 (1988): P a g e