memorandum date April 11, 2008 John McWilliams, DKA from Linda Krippner

Transcription

1 5309 Shilshole Avenue NW Suite 200 Seattle, WA phone fax memorandum date April 11, 2008 to from John McWilliams, DKA Linda Krippner subject Ingraham High School Renovation Project: Habitat Assessment and Landscape Plan Evaluation ESA Adolfson is pleased to present this habitat assessment and landscape plan evaluation for Seattle Public Schools Ingraham High School Renovation Project located at 1819 N 135 th Street in Seattle, Washington (Figure 1). Site Description The Ingraham High School site is 28 acres in size and is located in a residential neighborhood. The site is bounded by residential and arterial roads to the north, south, and west, and by the Helen Madison Pool and residential properties to the east (Figure 2). Most of the school buildings are on the north portion of the site, and the ball fields, track, and football field are on the south portion of the site (Figure 2). A mix of ornamental and native shrubs and trees are located along the perimeter of the site, with a park-like stand of conifer and Pacific madrone trees at the northwest corner and a native forest community on the east side of the site. Project Description The proposed project includes building demolition and construction and parking lot improvements and expansion. Seven portable buildings and one modular building totaling approximately 7,800 square feet will be demolished. A new classroom addition and courtyard will be attached to the west side of the existing school building on the northwest portion of the site. The new addition will be approximately 22,600 square feet and will extend into an existing stand of conifer and Pacific madrone trees. New paving and other improvements will be made to the parking lot south of the auditorium on the northeast portion of the site. Methods The study included a review of existing information and field visits on April 2 and April 8, 2008 by Linda Krippner, ESA Adolfson wildlife biologist, and Brooke Sullivan, ESA Adolfson arborist and landscape designer. The intent of the field visit was to evaluate existing habitat conditions, provide review of the arborist report titled Exceptional Tree Review at Ingraham High School (Cascade Design

2 Collaborative, 2007) on trees, and evaluate site plans with regards to the City of Seattle s Director s Rule Habitat was assessed and wildlife observations were recorded in different areas of the site. Trees were also evaluated visually for general health and for wildlife use, including nesting and roosting. Existing information reviewed included: Exceptional Tree Review at Ingraham High School (Cascade Design Collaborative, Inc., October 22, 2007); Environmental Checklist for Ingraham High School Renovation: Demolition and New Construction Project (URS Corporation, January 31, 2008); Ingraham High School Classroom Addition and Site Improvements: 50% Construction Documents. (Integrus Architecture, March 21, 2008); Ingraham High School Classroom Addition and Site Improvements: Landscape Drawings (Cascade Design Collaborative, Inc., April 2008 in progress); Habitats and Species Database (Washington State Department of Fish and Wildlife [WDFW], 2007); 2007 Natural Heritage Plan (Washington State Department of Natural Resources [WDNR], 2007); Upland Plant Associations of the Puget Trough Ecoregion, Washington (Chappell, 2006); Pacific Madrone Forests of the Puget Trough, Washington (Chappell and Giglio, 1999); and Aerial photography (King County, 2006). Review of Existing Information Our review of existing information included a review of existing maps, databases, and project documentation. Aerial Photo and WDFW Database Information The 28-acre project site is mainly developed, with a stand of trees in the northwest corner and a small tract of native forest on the east portion of the site. Neither area is contiguous with other forest patches located offsite, with the closest forest patch being about 0.4 mile east of the site. The east forest area extends onto land owned by Seattle Parks & Recreations, this are is identified as forested parkland in the Green Seattle Partnership 20- Strategic Plan. No priority habitats or species are identified by WDFW on the site (WDFW, 2007). Two priority habitat areas, identified as Urban Natural Open Space/Seattle City Parks, are located approximately 0.4 mile to the east and west of the project site. Single family residential development surrounds both of these priority habitat areas. No other priority habitat areas are located within 0.5 mile and no priority species are identified within one mile of the site. 2

3 Findings Exceptional Tree Review On October 19, 2007 the trees at Ingraham High School were reviewed by Margaret Harrison ISA (ISA Certified Arborist, Cascade Design Collaborative), and Bill Ames (Urban Forester, SDOT) in order to identify exceptional trees as defined by City of Seattle s Director s Rule The tree review focused on three areas: Area One is a stand of conifer and Pacific madrone trees located in the northwest corner of the site. Area Two is a grouping of five trees located along Ashworth Avenue North within a powerline corridor. Area Three is a native forest community located on the eastcentral portion of the site. No exceptional trees were identified in the three areas investigated. Recommendations were made for tree removal in Areas One and Two due to tree health and school safety requirements. Our field observations focused on the two site areas that contain native trees, referred to in the Exceptional Tree Review (Cascade Design Collaborative, 2007) as Areas One and Three. We also made observations along Ashworth Avenue North where several Douglas fir trees are located beneath and adjacent to a power line (Area Two). The northwest tree stand and east forest community resemble the Douglas fir-pacific madrone/salal association as described in WDNR (2007), Chappell (2006) and Chappell and Giglio (1999). Pacific madrone plant associations have conservation status because they are in decline and have limited distribution in the region. In addition, the fruits of Pacific madrone provide an important food source for many birds including band-tailed pigeon, a species in decline in the region (Chappell and Giglio, 1999). Northwest Tree Stand (Area One) The northwest tree stand, approximately 1.2 acre in size, is dominated by Douglas fir, with smaller numbers of western red cedar and Pacific madrone. Some of the Douglas fir and many of the Pacific madrone trees appear to be at least 50 years old. The Pacific madrones are located mainly in the west half of this area. This is a park-like stand of trees with mowed grass and trails beneath the dense tree canopy (Photos 1 and 2). Native vegetation is lacking in the understory with the exception of small clumps of salal present beneath a few trees in this stand (Photo 3). Wildlife observed in this stand included several birds that are also common in residential landscapes: Bewick s wren, American crow, northern flicker, dark-eyed junco, house finch, American robin, Anna s hummingbird, black-capped chickadee, and bushtit. Mole hills and eastern gray squirrel were also observed during the field visit. No nests were observed during the field visit. Right-of-Way (Area Two) 3

4 The five Douglas fir trees in the right-of-way have been topped and pruned to prevent interference with power lines. Their future growth is limited by their location in this right-of-way (Photo 4). Habitat functions are low in this area as these trees are not part of a contiguous forest community and have limited growth potential due to their location in the power line corridor. East Forest (Area Three) The east forest area, approximately 1.2 acre in size, extends onto the adjacent Seattle Parks & Recreation property. This forest is dominated by a mix of native conifer and deciduous trees as well as a dense native shrub understory (Photo 5). Native trees include Pacific madrone, Douglas fir, western red cedar, western white pine, and Pacific yew. Some of these trees likely meet the city s criteria for being exceptional trees. The shrub understory is dominated by salal and also contains rose, red huckleberry, bracken fern, Oregon grape, ocean spray, Indian plum, trailing blackberry, and sword fern. The dense salal, Oregon grape and red huckleberry shrubs are more than three feet high in some places. Numerous trails cross the area, and garbage is prevalent. Overall trees are younger in this forest area than in the northwest tree stand. Several healthy, young Pacific madrone trees are located in this forest area adjacent to the existing parking area. Invasive, non-native plants are growing densely in some areas of this forest, mainly near the forest edges. Scot s broom and English holly are mainly growing along the forest edges. English ivy is found throughout the forest, and is climbing trees located near the existing parking lot. Clematis was also observed. Wildlife observations included American robin, black-capped chickadee, dark-eyed junco, goldencrowned kinglet, house finch, American crow, northern flicker, spotted towhee, and red-breasted nuthatch. Two large stick nests were observed, one was in a western red cedar and the other in a Douglas fir tree. Both are located near the forest edge. The activity of American crows in the area during the survey and the nest shape, material and size indicate that they are likely to be crow nests. Project Impacts and Mitigation Measures Project impacts to native vegetation are limited to the northwest tree stand (Area One) and Ashworth Avenue North (Area Two). The east forest (Area Three) will be protected and the forest edge adjacent to the parking area will be enhanced. The new classroom addition will extend into the east portion of the northwest tree stand. Approximately 0.5 acre of the 1.2 acre northwest tree stand will be cleared for the classroom addition. Native trees to be removed in this stand due to the classroom addition and safety requirements are listed in Table 1. All of the 22 Pacific madrone trees in this stand will be removed because of their poor health and hazard potential following construction. At least three of the five Douglas fir trees located in the powerline corridor will be removed due to their hazard potential. 4

5 Table 1. Count of native trees to be removed and planted. Native trees: Removed Planted Douglas fir Western red cedar Pacific madrone 22 Total native trees Native trees that are lost in the northwest tree stand and along Ashworth Avenue North will be replaced with native conifer trees at a ratio of about. Replacement with Pacific madrone is not recommended in the northwest forest area because there is high potential for disease to be present in soils, given the condition of the existing Pacific madrone trees. Native conifers will be planted in the northwest tree stand and several native conifer groves will be established throughout the site landscaping areas. Native shrubs and ferns will also be planted in several site areas. Native shrub understory will be planted in some areas of the northwest tree stand, in particular where Pacific madrone trees will be removed. Existing pavement will be removed from outside portions of the east parking area and restored with native shrub and groundcover, enhancing the edge of the east forest. Native shrubs and ferns will also be planted in the new atrium area located in the center of the classroom addition. Native tree and shrub plantings will also be used to enhance habitat throughout new landscaping areas in other site areas. Compliance with Director s Rule The Director s Rule was written to clarify the SEPA Plants and Animals Policy in the Seattle Municipal Code (SMC ). Three main criteria described in SMC N.2a, 2c, and 2d are presented as policies under this rule. In the following three sections, these criteria are stated in italics along with an explanation of how this project proposal complies with each of these three criteria. SMC N.2a It is the City s policy to minimize or prevent the loss of wildlife habitat and other vegetation which have substantial aesthetic, educational, ecological, and/or economic value. The project has been designed to prevent the loss of native forest habitat and minimize the removal of native trees. The east parking lot was designed to prevent the loss of any east forest habitat. The loss of native trees in the northwest tree stand and power line corridor has been minimized to the extent possible given school safety requirements. Although madrone plant associations are valuable in this region, the ecological value of the trees to be removed is limited due to disturbed understory conditions, small habitat patch sizes, and urban residential surroundings. SMC N.2c When the decision maker finds that a proposed project would reduce or damage: 1) rare, uncommon, unique or exceptional plant or wildlife habitat; 2) wildlife travelways; or, 3) habitat diversity for species (plants or animals) of substantial aesthetic, educational, 5

6 ecological or economic value. The decision maker may condition or deny the project to mitigate its adverse impacts. Such conditioning or denial is permitted whether whether or not the project meets the criteria of the Overview Policy set forth in SMC Section ; provided, that for any project subject to the City s Shoreline Master Program, the Overview Policy set forth in SMC Section shall apply. Some of the young Pacific madrone trees and other trees located in the east forest and immediate parking lot area may meet the criteria for being exceptional (Photo 5). None of these trees will be removed or affected by the project design proposed. As described above, Pacific madrone plant associations are in decline in the region. Therefore, considerations have been made to avoid tree removal and protect as many trees in the northwest tree stand as possible, while still meeting school safety requirements. Wildlife travelways are not specifically defined in SMC but are presumed to be connections to other native habitats for uninterrupted movement between habitat areas. Wildlife travelways on the site are limited due to the presence of surrounding residential development, major arterial roads, and the lack of connection to nearby habitats. However, for animals that fly such as birds and bats the forested portions of the site may function as a connecting link between other native forest areas in the city, especially for urban-adapted species. These habitat areas will be preserved by the retention and enhancement of more than half of the northwest tree stand and all of the east forest. Additional native conifer groves will also be established on the site to compensate for the trees lost in the northwest tree stand and along Ashworth Avenue North. Habitat diversity in the east forest will be preserved, and it will be enhanced in the remaining area of trees in the northwest portion of the site. SMC N.2d Mitigating measures may include but are not limited to: i. Relocation of the project on the site; ii. Reducing the size or scale of the project; iii. Preservation of specific on-site habitats, such as trees or vegetated areas; iv. Limitations on the uses allowed on the site; v. Limitations on times of operation during periods significant to the affected species (i.e., spawning season, mating season, etc.); and vi. Landscaping and/or retention of existing vegetation. The proposed project meets several of the mitigating measures listed under SMC N2d, including preservation of specific on-site habitats, such as trees or vegetated areas. The 1.2 acre east forest patch will be retained, protected, expanded, and enhanced. More than half of the northwest tree stand will be protected and enhanced with additional native tree plantings to replace those removed for safety concerns. The remaining northwest tree stand area will also be enhanced with native understory plantings. The replanting plan for other areas is also designed to preserve ecological value. 6

7 Redeveloped areas will be landscaped with a variety of trees and shrubs that include new groves of native conifer trees. The tree removal plan has been revised to protect additional trees in the northwest tree stand. Additional conifer trees will be planted in the northwest tree stand and in groves in other areas of the landscaping in order to replace those that are removed during project construction. The northwest tree stand will also be enhanced with native shrubs and herbs, increasing habitat diversity. The east forest will be completely protected. Conclusions and Recommendations Based on our review of Director s Rule , the exceptional tree review (Cascade Design Collaborative, 2007), and field investigations, the project proposal meets the intent of SMC N.2a, 2c, and 2d. Native forest habitat will be preserved on the east portion of the site and landscaping will include native species. Trees removed in the northwest tree stand will be replaced with additional native conifer trees planted in the remaining stand and in other landscape areas. Site redevelopment is also designed to meet the goal of no net loss of tree canopy allowing for tree-maturation over time. No exceptional trees were identified in the Exceptional Tree Review at Ingraham High School (Cascade Design Collaborative, 2007). We disagreed with this conclusion as we observed several Pacific madrone trees and other trees in the east forest that likely meet the criteria for being exceptional in accordance with Seattle s Director s rule None of these trees will be affected by the project. In addition to the planned mitigation measures, ESA Adolfson recommends that the following measures be considered for incorporation into the final plan in order to improve wildlife habitat conditions: Remove non-native invasive species including English ivy, Scot s broom, English holly from the east forest, and replace them with native shrubs to prevent their re-establishment and enhance this forest area. Use additional native species for landscape plantings. Retain at least portions of the existing dead/dying trees for cavity-nesting wildlife in the northwest forest stand if possible considering safety concerns. Minimize impacts to breeding birds by removing large trees outside of the breeding season, late summer through winter. Continue to remove invasive plants in all forest and landscaped areas, and enhance these areas with native plantings until these areas are well established with dense native plant communities reflective of the Douglas fir Pacific madrone/salal association existing on the site. Limitations Within the limitations of schedule, budget, seasonal constraints, and authorized scope-of-work, we warrant that this study was conducted in accordance with generally accepted environmental science practices, including the technical guidelines and criteria in effect at the time this study was performed, as outlined in the Methods section. The results and conclusions of this report represent the authors' best professional judgment, based upon information provided by the project proponent in addition to that obtained during the course of this study. No other warranty, expressed or implied, is made. 7

8 Attachments: Figure 1. Vicinity Map Figure 2. Project Site Photos 1 through 5 8

9 Feet 105th SOURCE: King County, 2002 Northgate 105th I5 1st 10th 5th Project Site Roosevelt 125th Exit 174 State Hwy 99 Exit 175 State Hwy 523 Legend Project Site Ingraham SEPA Figure 1 Vicinity Map King County, WA Roosevelt I5 Greenwood G:\ENVIR IMPACTS\2008 Projects\208245_Ingraham_SEPA\05_Graphics_GIS_Modeling\GIS\Vicinity_Map.mxd(MH 04/03/2008) 1,200 tm ins te r Meridian W es Exit 145th Project Area 5 13 th 135th 130th 125th Northgate W es tm ins te r

10 North 135th Street Northwest Tree Stand (1.2 acres) Ashworth Avenue North G:\ENVIR IMPACTS\2008 Projects\208245_Ingraham_SEPA\05_Graphics_GIS_Modeling\GIS\project_site.mxd (MH 04/01/2008) Helen Madison Pool Text East Forest (1.2 acres) North 130th Street Feet SOURCE: King County, 2002 (Aerial Photo) Legend Project Site Ingraham SEPA Figure 2 Project Site King County, WA

11 Ingraham High School Renovation Project Photo 1. Northwest tree stand (April 2, 2008). Photo 2. Trail through northwest tree stand (April 2, 2008).

12 Ingraham High School Renovation Project Photo 3. Salal growing beneath Pacific madrone in northwest tree stand (April 2, 2008). Photo 4. Douglas fir beneath power line near Ashworth Avenue North (April 2, 2008).

13 Ingraham High School Renovation Project Photo 5. East forest edge near parking lot (April 8, 2008).