T REE I N V E N T O R Y A N D R E T E N T I O N P L A N R E P O R T Proposed Subdivision at 4320 Island Crest Way, Mercer Island, WA

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1 T REE I N V E N T O R Y A N D R E T E N T I O N P L A N R E P O R T Proposed Subdivision at 4320 Island Crest Way, Mercer Island, WA Prepared for: Prepared by: Alan Chiu Mercertech International, LLC c/o Jayson Taylor 4320 Island Crest Way Mercer Island, WA jayson.m.taylor@gmail.com October 27, 2017

2 The Watershed Company Reference Number: The Watershed Company Contact Person: Lucas Vannice, ISA-Certified Arborist Cite this document as: The Watershed Company. October Tree Inventory and Retention Plan Report: Mercer Island Chiu Subdivision. Prepared for Mercertech International, LLC.

3 T A B L E O F C O N T E N T S Page # 1 Introduction Site Description Inventory Methodology Trees Included in this Study Regulated Trees Off-Site Trees located near the project area Authority Mapping Attribute Data Collection Data Management Limitations Tree Inventory Results Local Regulations Regulated Tree MICC Tree Retention MICC Tree Protection MICC Tree Replacement MICC Photos Tree Retention Plan Tree Retention Tree Removal Tree Replacement / Conceptual Planting Plan References Appendix A Tree Table Tree Inventory and Retention Plan Report - I

4 L I S T O F F I G U R E S Figure 1. Vicinity map Figure 2. Approximate location of study area (yellow) Figure 3. View looking northwest at the northwest corner of parcel (Photo taken May 16, 2017) Figure 4. View from center of property, near road looking over Wetland A toward northeast corner of property (Photo taken September 21, 2016) Figure 5. View from center of property, near road, looking over Wetland A toward southeast corner of property (Photo taken May 16, 2017) Figure 6. View looking northesat at cluster of cottonwood within Wetland A, near culvert for Watercourse A (Photo taken September 21, 2016) Figure 7. View looking southwest at southern entrance to subject parcel off Island Crest Way (in background) (Photo taken May 16, 2017) Figure 8. Looking toward southeast from Island Crest Way at northern entrance to parcel (Photo from Google Street View, 2011) L I S T O F T A B L E S Table 1. Attributes recorded for all inventoried vegetation and that are presented in the spreadsheet database Table 2. Replacement ratios for tree removed per (MICC (A.)) Table 3. Trees to be removed in the study area based on the preliminary plat improvements and proposed building pads Tree Inventory and Retention Plan Report - II

5 R E S P O N S I B L E P A R T I E S APPLICANT: Alan Chiu Mercertech International, LLC c/o Jayson Taylor 4320 Island Crest Way Mercer Island, WA PROJECT ENGINEER: Eli Zehner, PE CHS Engineers Bellevue, WA Bel-Red Rd., Suite 101 Bellevue, WA (425) ext. 19 PREPARER OF THE TREE RETENTION PLAN REPORT: Lucas Vannice, Arborist The Watershed Company th Street S Kirkland, WA (425) Tree Inventory and Retention Plan Report - III

6 T R E E I N V E N T O R Y A N D R E T E N T I O N P L A N R E P O R T PROPOSED SUBDIVISION AT 4320 ISLAND CREST WAY, MERCER ISLAND, WA 1 INTRODUCTION This report has been prepared to support the subdivision application for the parcel located at 4320 Island Crest Way (parcel # ; subject property) in the City of Mercer Island (City). The applicant proposes to divide the 1.67-acre parcel to include five single-family residential lots and one tract. The purpose of this report is to summarize proposed removal, retention, and replacement of trees on the subject property necessary to permit the preliminary subdivision improvements which include grading, a roadway, sewer, water, and storm drainage improvements. This report is based on plans (dated October 16, 2017) provided by the project engineer, CHS Engineers, and will document how the preliminary subdivision meets the Mercer Island City Code (MICC) tree ordinance requirements (MICC Trees). Note that previous tree removal associated with a Notice of Correction (Code Compliance Case: CE ) is not addressed in this report, but is addressed in the critical area study prepared for the subject property (The Watershed Company, October 2017). Per Mercer Island s Subdivision Improvements submittal requirements, preliminary subdivision improvement will be completed prior to recording of the final plat and prior to the issuance of a building permit. Tree retention on buildable lots has been determined and is addressed in this report and depicted in the associated Tree Retention Plan; however, tree removal on buildable lots is expected to occur after approval of construction permits. A tree inventory was conducted on the property to quantify and characterize all significant trees prior to site plan development. The study area for the tree inventory (Figures 1 and 2) includes the 1.67-acre subject parcel (parcel # ); portions of the Island Crest Way right-of way to the west and south of subject parcel; as well as portions of the following parcels, which were screened for trees with driplines extending onto the subject parcel: , -9154, -9160, -9180, -9147, -9148, -9178, and -9139, and

7 PARCEL # CITY OF MERCER ISLAND R.O.W. PARCEL # PARCEL # PARCEL # Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision Study Area Figure 1. Vicinity map. PARCEL # PARCEL # PARCEL # PARCEL # PARCEL # PARCEL # PARCEL # Figure 2. Approximate location of study area (yellow) and associated parcel boundaries (red). 2

8 The Watershed Company October SITE DESCRIPTION The subject property is located on the west side of the City, northeast of the intersection of Island Crest Way and SE 44 th Street, in Section 18 of Township 24N, Range 05E of the Public Land Survey System. It is zoned Residential Single Family (R 9.6). The subject property is currently accessed from the west via Island Crest Way. It is 1.67 acres in size and currently contains two single-family homes, a throughroad connecting the two homes, and three accessory structures (sheds). The site contains three wetlands and a watercourse, as confirmed in the Wetland and Watercourses Delineation Report prepared by The Watershed Company on May 31, The largest of these wetlands is Wetland A, a slope-depressional, Category III wetland which encumbers the majority of the eastern portion of the parcel, and has a standard buffer of 50 feet. This wetland was originally forested with alder and cottonwood with possibly a few conifers (King County imap 2013 aerial basemap), but has since been cleared and partially filled with wood chips. Wetland B is a slope-depressional, Category III wetland. Dominant vegetation includes red alder and western redcedar trees with an understory of Scouler s willow, Himalayan blackberry, and salmonberry. Wetland B has a 50-foot standard buffer. Wetland C is a slope-riverine, Category III wetland that continues along Watercourse A and has a buffer of 50 feet. Dominant vegetation consists of western redcedar, salmonberry, Himalayan blackberry, skunk cabbage, knotweed, and various grasses. Watercourse A originates in Wetland A and flows west, exiting Wetland A via a culvert into Wetland B. Watercourse A is intermittent in the upstream segment, loses definition within Wetland B, and the bed and bank characteristic become defined once again as it flows west through Wetland C before existing via a culvert under Island Crest Way. For areas of Watercourse A with seasonal flow, the standard buffer is 35 feet. Areas of perennial flow have a standard buffer of 50 feet. For areas where Watercourse A is piped, a standard buffer of 25 feet is required. For all wetlands and the watercourse, the buffer can be reduced to a minimum buffer width of 25 feet with buffer enhancement. Outside of wetland and watercourse areas, the site consists of native and nonnative deciduous and coniferous trees with ornamental shrubs and invasive plants in the understory. Along the parcel line near Wetland A, Leyland cypress 3

9 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision have been planted approximately 2 feet on-center. Along the west parcel line, near the Island Crest Way right-of-way, north of Wetland C, cherry laurel forms a continuous hedge. 3 INVENTORY METHODOLOGY 4 The Watershed Company (Watershed) arborist conducted a field-based tree inventory on May 16, 2017 and August 24, 2017, using the methods detailed below. The methodology was developed to comprehensively identify, describe and map all regulated trees in the study area. This report is written to meet the MICC standards in-place at date of report. In anticipation of the new City code provisions going into effect November 2, 2017, the project has been designed to meet the proposed code to the extent feasible. Portions of this project which meet the proposed code are provided in parenthesis in this report. 3.1 Trees Included in this Study Regulated Trees Subject trees within the study area were determined to be significant using the definition in MICC Section The City defines a regulated tree as any conifer tree that is six feet tall or more or any deciduous tree with a diameter of more than six inches. A round one-and-one-quarter-inch-wide, numbered aluminum tag was affixed to the trunk of all regulated trees presumed to be located within the subject study area (tree tag # , # , # , # , and 968-1,013). Although not on the subject parcel, permission was granted from a neighboring parcel owner (parcel # ) to tag trees # and # These were tagged due to the findings in the Trip Generation & Sight Distance Evaluation draft letter prepared by Transportation Engineering NorthWest on August 22, 2017 mentioning that vegetation clearing may be required within this parcel to achieve adequate site distance triangles, given the design speed of Island Crest Way Off-Site Trees located near the project area All visible regulated trees that have driplines extending over the subject property line were included in this inventory (MICC C.1.b). Additionally, trees located within the City right-of-way west and south of the subject parcel and trees along the west edge of parcel were inventoried due to findings in the Trip Generation & Sight Distance Evaluation draft letter prepared by Transportation Engineering NorthWest on August 22, Arborists inventoried these trees from the subject property or right-of-way; they were not

10 The Watershed Company October 2017 tagged but were given unique and sequential identification numbers (beginning with #100 and ending at #132). 3.2 Authority Online resources were referenced to verify both the scientific and common names of subject plants for reporting purposes. For landscape trees and shrubs (plants not native to Washington State), the Oregon State University Department of Horticulture online landscape plant database (Oregon State University 2017) was referenced. Native trees and shrub names were verified using the University of Washington WTU herbarium website (University of Washington 2017) and the USDA plant database (United States Department of Agriculture 2017). 3.3 Mapping CHS Engineers survey-located the subject trees following Watershed field work. Survey data and preliminary plat plans were provided to Watershed in AutoCAD file format on October 13, Attribute Data Collection The attributes collected during the field survey are described in Table 1, below. The database, included with this study as a PDF, contains the data collected for each tree inventoried. General attributes documented for all inventoried trees include the date of assessment, unique identification number of tree, and name of plant species. Physical attributes include number of stems, dbh, height, canopy radius, condition, and assessment notes. In general, tree diameter was measured at four feet above the ground surface (diameter at breast height, or dbh ) using a graduated metal logger s dbh tape. Trees with multiple trunks arising from the ground were measured using methodology from Guide for Plant Appraisal (Gooding, et al. 2000). The crosssectional areas of stems contributing to the canopy were summed and used to generate a singular combined dbh for the tree. The singular dbh number allows for comparison to other single-stemmed trees and for more accurate permitting and tree retention calculations. When dbh resulted in a fraction, it was rounded to the nearest whole number. Methodology for measuring diameter of trees with major leans, on steep slopes, and with multiple trunks or stems generally followed those outlined in the Guide for Plant Appraisal (Gooding, et al. 2000). Visual estimates of trunk diameter were used where direct access to the tree was not allowed. 3.5 Data Management Tree data were recorded on Panasonic Toughpad using ESRI s ArcPad software. Data points were located and recorded using ArcPad aerial photography and site survey for reference. Tree attribute information and related 5

11 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision points were collected as a shapefile. Shapefile data were then exported and subsequently reviewed, corrected, projected and organized into a searchable database using ArcMap. 6

12 The Watershed Company October 2017 Table 1. Attributes recorded for all inventoried vegetation and that are presented in the spreadsheet database. Attribute DATE OF ASSESSMENT ID NUMBER SCIENTIFIC NAME COMMON NAME Description of Attribute Date that the Watershed Company field crew tagged and assessed the tree or shrub. Unique number assigned to an assessed tree. This number corresponds to the tag number in the field. Formal scientific name conforming to the International Code of Nomenclature. Name that is based on normal or common language of the Pacific Northwest. DECIDUOUS/EVERGREEN Notes whether a tree is considered deciduous or evergreen. STEMS Number of trunks or shoots that contribute significantly to the canopy. DBH Diameter at Breast Height; or 4.5 feet from the ground surface. See Section 3.4 for variations. DBH2 DBH of secondary and other minor stems. HEIGHT CANOPY RADIUS CONDITION Approximate distance from the ground surface at the trunk to the highest point of the subject tree as visually estimated. Measurement from the stem to the average drip line, or end of branches. Critical root zone Health rating of an assessed tree using a 5-tier system as follows: 1 Excellent: No apparent problems with the tree. Form is exemplary for the species. 2 Good: Few minor defects such as crossed branches, minor foliage die-back, minor trunk damage, or unbalance canopy. 3 Fair: Several minor problems exist. 4 Poor: Major defects visible such as significant trunk decay, codominant leaders with included bark, significant canopy dieback, major cracks in a stem or major limbs, and/or other structural problems. Topped trees are generally considered poor. 5 Dead or dying: Tree is dead or is in a state of significant decline. 7

13 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision 4 LIMITATIONS Trees presumed to be located outside of subject property were not tagged and were assessed from various distances. For off-site trees, attribute data requiring direct contact (such as trunk diameter) is a visual estimate only and may vary slightly from the conditions at the time of the assessment. Trees were identified using the vegetative characteristics present at the time of the inventory. Tree size and condition vary with time. The attributes presented in this study represent a snapshot at the time of the field work and may not necessarily be accurate in the future. The condition of any remaining tree following the proposed land use action will ultimately be affected by root disturbance, new wind exposure (windthrow), etc. The health condition ratings indicated the supporting material attached to this report does not represent the condition of the tree during or following construction. Follow-up monitoring may be required to ensure changing site conditions do not result in hazardous trees or tree components. 5 TREE INVENTORY RESULTS A total of 257 regulated trees were tagged as part of the tree inventory. Of these, 204 regulated trees are rooted on the subject property or right-of-way; 31 are rooted off-site, but within 15 feet of the subject property; and 17 are rooted within potential conflict area for required site distance triangle. A copy of the tree data table, including tree species, size, height and condition, is included in the Tree Table (Appendix A). The largest tree on-site is a two-stem 43.8-inch-diameter American chestnut (#820). Eleven other deciduous trees (6 bigleaf maples, 2 red alders, 2 European white birches, 1 pin oak) measure over two feet in diameter at 4.5 feet above the ground on the property. One Douglas-fir, one western white pine, and one Deodar cedar also measured over two feet in diameter at 4.5 feet above the ground. Of all trees inventoried, 201 are evergreen and 56 trees are deciduous. No trees on-site are known to be designated landmark trees. 8

14 The Watershed Company October LOCAL REGULATIONS Regulations regarding the removal, retention, replacement, and protection of trees in the subject property are detailed under Chapter (Trees) of the MICC at date of this report. 6.1 Regulated Tree MICC According to MICC 19.16, large (regulated) trees are defined as any conifer tree that is six feet tall or more or any deciduous tree with a diameter of more than six inches. 6.2 Tree Retention MICC Per MICC B, a permit is required for removal of any large (regulated) tree within a critical tree area or as a result of construction work. According to MICC , Critical Tree Area is an area on a lot where trees are providing certain protections to a geologic hazard area, watercourse or its buffer, wetland or its buffer, and a protected slope area. The permit will be granted if it is proven that cutting trees is necessary to enable construction work on the property and the owner has used reasonable best efforts to design and locate any improvements and perform the construction work in a manner that preserves regulated trees per MICC B.2. Plan Compliance. Site plans were developed after tree inventory work was conducted. Several preliminary plat layouts have been explored including a sixlot layout, as opposed to five. Current impacts to trees are a result of general site grading and building envelope requirements. As part of this project, standard buffers have been reduced to 25 feet (only where necessary to accommodate single-family residential development). All trees removed within wetlands or reduced wetland buffer will be snagged. To minimize impacts to trees, utilities are proposed under the road and dry utilities are located directly adjacent to the road. Additionally, the required stormwater vault will be under the turnaround area between Lot 1 and Lot 2. A large group of trees will be included for protection and retention in the southwest portion of the property, all of which are within critical area buffer. Under previous lot subdivision configurations, up to five trees were proposed for removal at this location. 6.3 Tree Protection MICC Retained trees must be protected from construction activities (MICC b) with placement of tree protection fencing installed at the regulated tree driplines (City of Mercer Island Development Services Group n.d.). 9

15 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision Plan Compliance. Retained trees will be protected from construction using tree protection fencing as shown in the Tree Retention Plan (Appendix A). Protected trees should not be disturbed during demolition or construction activities. In some locations, work will occur within the driplines of trees that are recommended for retention. At these locations, mitigation measures should be employed to minimize potential root zone impacts to retained trees. Recommended mitigation measures are described in Section 8 (Tree Retention Plan), below. 6.4 Tree Replacement MICC All trees that are to be cut must be replaced on the subject property, according to the MICC. The City Arborist will determine the number of replacement trees required by applying a replacement ratio, which ranges from 0:1 to 4:1. Replacement trees must meet the criteria outlined in MICC and are required to be maintained in a healthy condition for a period of two years after planting. Plan Compliance. All healthy regulated trees to be removed on the subject property outside of the reduced critical area buffer will be replaced at the ratio outlined in the MICC to be adopted November 2, 2017 ( A). See Table 2 for proposed replacement trees based on proposed code. Trees removed within critical areas or their buffers will be replaced at a 4:1 ratio, and snagged. Replacement tree species will be selected to replace characteristics of the removed tree(s). For example, western red cedar and Sitka spruce are suitable species for replacement of western white pine. The following ratios are proposed for removed trees outside of proposed critical area buffers: Table 2. Replacement ratios for tree removed per (MICC (A.)) Trunk size (DBH) of healthy* tree to be removed (inches) Number of required replacement trees Less than 10 inches 1 10 inches up to 24 inches 2 24 inches up to 36 inches 3 More than 36 inches and any exceptional tree(s) 6 10

16 The Watershed Company October PHOTOS Figure 3. View looking northwest at the northwest corner of parcel (Photo taken May 16, 2017). Figure 4. View from center of property, near road, looking over Wetland A toward northeast corner of property (Photo taken on September 21, 2016). 11

17 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision Figure 5. View from center of property, near road, looking over Wetland A toward southeast corner of property (Photo taken on May 16, 2017). Figure 6. View looking northeast at cluster of cottonwood within Wetland A, near culvert for Watercourse A (Photo taken September 21, 2016). 12

18 The Watershed Company October 2017 Figure 7. View looking southwest at southern entrance to subject parcel off Island Crest Way (in background) (Photo taken May 16, 2017). Figure 8. View looking southeast from Island Crest Way at northern entrance to parcel (Photo from Google Street View, 2011). 13

19 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision 8 TREE RETENTION PLAN The applicant is proposing a five-lot subdivision of the subject parcel with access from Island Crest Way. This Tree Retention Plan is based upon preliminary plat plans provided by CHS Engineers on October 13, Tree Retention A total of 188 trees will be retained on subject parcel. By number, this represents 89 percent of inventoried trees on subject parcel. Tree protection fencing will protect retained trees as shown in the Tree Retention Plan (see civil). Retained trees should not be damaged during demolition of existing structures or construction of new features. Many of the trees to be retained are located in the existing wetland critical areas and near the subject parcel perimeter. The largest stand of native forest on-site is located near Wetland C, in the southwest portion of the parcel and dominated by western redcedar and bigleaf maple. This stand will remain intact under this tree retention plan. Additionally, over 125 evergreen trees will be preserved along the eastern perimeter of the parcel. Some trees located on-site that are proposed for retention will sustain drip-line impacts (#729 - #732) based on the proposed plans. These impacts are considered to be relatively minor due to location of existing retaining wall and when considering the proposed impact is soil fill. Care should be taken to prevent damage to trees when driplines are located in construction work areas. In order to minimize drip-line impacts, mitigation measures should be employed when feasible while conducting work within the driplines of all retained trees. Recommended mitigation measures include the following: 14 Reduce compaction: Where root removal will not be required, temporarily apply 6 to12 inches of coarse mulch in retained tree driplines located outside of tree protection fencing to prevent compaction of soil by heavy equipment. Alternatives to trenching for utility installation: Use an air-spade to air-excavate or hand-dig around tree roots to prevent significant damage or loss when installing utilities. Horizontal drilling, tunneling, or boring would also reduce impacts to roots and allow for installation of utilities. The City arborist may also require exploratory trenching prior to grading to identify location of tree roots. Minimize injury: When tree roots must be removed, cut roots cleanly using a sharp saw or pruners. Do not rip or cut tree roots with heavy equipment.

20 The Watershed Company October 2017 Construction oversight: The City arborist may require an ISAcertified arborist to be present on-site during construction activities within the driplines of retained trees to monitor tree protection, assist with changes in the field, and document construction impacts. Monitor: An ISA-certified arborist should monitor retained trees after construction activities to identify changes in the health and structural conditions. Despite best efforts, retained trees may fail as a result of construction and may require removal. 8.2 Tree Removal The proposed preliminary plat design directly or significantly impacts 23 regulated trees in the study area. These trees should be removed prior to construction activities (Table 3). Eighteen (18) of the trees to be removed are located within the proposed building footprint areas and require removal for development to occur, primarily based on proposed grading. Five (5) trees (#793, #794, #795, #817, and #818) will require removal as part of the wetland creation area as these trees are not expected to be viable after the proposed grading work. These trees should be snagged into habitat features at a height that would not be considered hazardous. Trees proposed for removal are shown in Table 3 below and generally consist of non-native species or small native trees in fair or poor condition. In contrast, larger and healthier western redcedar and bigleaf maple trees will be retained. Table 3. Trees to be removed in the study area based on the preliminary plat improvements and proposed building pads. Tree ID Common Name Scientific Name DBH* (in.) Condition Replacement Ratio (X:1) 734 Norway spruce Picea abies Poor European white birch Betula pendula Fair Scots pine Pinus sylvestris Fair Leyland cypress xhesperotropsis leylandii Good Leyland cypress xhesperotropsis leylandii 6 2 Good China fir Cunninghamia lanceolate Good Western redcedar Thuja plicata Good Plum Prunus domestica Fair Oregon ash Fraxinus latifolia Fair Japanese snowbell Styrax japonicas Poor American chestnut Castanea dentate Fair Bigleaf maple Acer macrophyllum Good 6 15

21 Tree Inventory and Retention Plan Report Mercer Island Chiu Subdivision Tree ID Common Name Scientific Name DBH* (in.) Condition Replacement Ratio (X:1) 822 Western redcedar Thuja plicata Good Bitter cherry Prunus emarginata 7 3 Fair Austrian pine Pinus nigra Poor Scotch pine Pinus sylvestris Fair Bigleaf maple Acer macrophyllum Poor European white birch Betula pendula Fair Scotch pine Pinus sylvestris Fair Pacific madrone Arbutus menziesii Fair Bigleaf maple Acer macrophyllum Fair Western redcedar Thuja plicata Good Douglas-fir Pseudotsuga menziesii Fair 1 *Only largest DBH is shown in this table if there are multiple stems present. Replacement Total: 81 Tree Replacement / Conceptual Planting Plan Based on the tree replacement requirements for areas outside of critical areas or their buffer as outlined in the code to take effect November 2, 2017(MICC ), as well as a 4:1 replacement for trees within the reduced 25-foot buffer as outlined in current code at time of this report, 81 trees should be planted on the property to compensate for impacts resulting from site development (Table 3). Replacement trees should be primarily those species native to the Pacific Northwest. Large native coniferous trees (such as Douglas-fir, western red cedar, grand fir, and western white pine) should be used where practicable to preserve the character of the neighborhood and to restore function to critical areas. All replacement trees shall be at least six feet tall at the time of installation. Tree replacement, with the exception of the tree replacement for the five trees within the wetland creation area that have already been compensated for, will be shown on the site landscape plan to be developed by the landscape architect. Replacement trees are expected to be preferentially planted in the northern portion of Wetland A (area not restored as part of the Notice of Correction). Additional impacts to trees are not anticipated as specific lot plans develop. If additional impacts occur as a result of demolition or construction activities, tree replacement will be required to compensate for any impacts not presented in this report. Tree replacement should occur after on-site construction and individual lot improvements are complete. 16

22 The Watershed Company October REFERENCES Allen, E. A., D. J. Morrison, and G. W. Wallis Common Tree Diseases of British Columbia. Victoria, British Columbia: Natural Resources Canada, Canadian Forest Service. City of Mercer Island Development Services Group. n.d. "Tree Permits." Tree Protection and Submittal Requirements. Accessed June 20, City of Seattle Seattle, Washington - Municipal Code. March Council of Tree & Landscape Appraisers Guide for Plant Appraisal, 9th Edition. Chicago: International Society of Arboriculture. Dunster, Julian A., E. Thomas Smiley, Nelda Matheny, and Sharon Lilly Tree Risk Assessment. Champaign, IL: International Society of Arboriculture. Gooding, Richard F., James B. Ingram, James R. Urban, Lewis B. Bloch, William M. Steigerwaldt, Richard W. Harris, and Ellis N. Allen Guide for Plant Appraisal. 9th. Edited by Peggy Currid. Champaign, IL: International Society of Arboriculture. Jacobson, Arthur Lee Trees of Seattle, Second Edition. Seattle: Arthur Lee Jacobson. Matheny, Nelda P., and James R. Clark A Photographic Guide to the Evaluation of Hazard Tress in Urban Areas. Pleasanton: HortScience, Inc. Mercer Island. n.d. TREES and CONSTRUCTION. Mercer Island. MICC City of Mercer Island City Code. January 4. Oregon State University Landscape Plants: Images, Identification, and Information. Edited by Patrick Breen. October 04. Accessed United States Department of Agriculture Natural Resources Conservation Service. October 04. Accessed University of Washington WTU Image Collection: Plants of Washington. October 04. Accessed Washington Department of Fish and Wildlife. n.d. Priorty Habitats and Species (PHS). Accessed April 8,

23 The Watershed Company October 2017 A P P E N D I X A Tree Table Appendix A - I

24 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 100 Malus domestica (Apple) D Prunus emarginata (Bitter cherry) D broken main leader at 50' 102 Pinus monticola (Western white pine) E Pinus monticola (Western white pine) E Picea sitchensis (Sitka spruce) E Tsuga canadensis (Canadian hemlock) E Tsuga canadensis (Canadian hemlock) E Sorbus aucuparia (European mountain ash) D Cedrus deodara (Deodar cedar) E Prunus avium <cultivated> (Fruiting Cherry) D sig. ivy on trunk 110 Crataegus monogyna (Common hawthorn) D Fraxinus latifolia (Oregon ash) D Pseudotsuga menziesii (Douglas-fir) E Fraxinus latifolia (Oregon ash) D Gleditsia triacanthos (Honeylocust) D Thuja plicata (Western red cedar) E chlorotic foliage 116 Thuja plicata (Western red cedar) E flagging 117 Thuja plicata (Western red cedar) E Thuja plicata (Western red cedar) E Acer macrophyllum (Bigleaf maple) D Thuja plicata (Western red cedar) E chlorotic foliage, stressed cone crop 121 Hesperotropsis leylandii (Leyland cypress) E Thuja plicata (Western red cedar) E Betula pendula (European white birch) D Betula pendula (European white birch) D Betula pendula (European white birch) D leader failure 126 Thuja plicata (Western red cedar) E Thuja plicata (Western red cedar) E Prunus avium <cultivated> (Fruiting Cherry) D Prunus avium <cultivated> (Fruiting Cherry) D decay in trunk; necrotic foliage; deadwood 130 Prunus avium <cultivated> (Fruiting Cherry) D deadwood; chlorotic foliage 131 Prunus avium <cultivated> (Fruiting Cherry) D significant ivy on trunk 132 Pseudotsuga menziesii (Douglas-fir) E topped for utility lines; significant ivy on trunk 652 Pseudotsuga menziesii (Douglas-fir) E topped for power line 653 Tsuga heterophylla (Western hemlock) E Pseudotsuga menziesii (Douglas-fir) E growing into power lines 655 Pinus sylvestris (Scots pine) E Prunus cerasifera 'thundercloud' (Cherry plum) D poor branch form 657 Quercus palustris (Pin oak) D ivy on trunk 658 Pseudotsuga menziesii (Douglas-fir) E Pinus sylvestris (Scots pine) E necrotic foliage

25 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 660 Pseudotsuga menziesii (Douglas-fir) E Pseudotsuga menziesii (Douglas-fir) E self corected lean 668 Pinus sylvestris (Scots pine) E topped for utility line 669 Pseudotsuga menziesii (Douglas-fir) E topped for utility line 670 Pseudotsuga menziesii (Douglas-fir) E topped for utility line; poor root flare 671 Pseudotsuga menziesii (Douglas-fir) E Pseudotsuga menziesii (Douglas-fir) E topped for utility line 729 Arbutus menziesii (Pacific madrone) E % of dripline impervius 730 Thuja plicata (Western red cedar) E retaining wall 1-ft from trunk 731 Thuja plicata (Western red cedar) E included bark 732 Arbutus menziesii (Pacific madrone) E not on survey 733 Arbutus menziesii (Pacific madrone) E ft from retaining wall; ivy on trunk; self-corrected lean 734 Picea abies (Norway spruce) E low lcr 735 Betula pendula (European white birch) D ivy on trunk; co-dominant from base 736 Pinus sylvestris (Scots pine) E phototropically oriented 737 Ginkgo biloba (Maidenhair tree) D not on survey 738 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Prunus domestica (Plum) D low lcr 741 Prunus domestica (Plum) D low lcr 742 Prunus domestica (Plum) D low lcr; not on survey 743 Prunus domestica (Plum) D Prunus domestica (Plum) D low lcr; not on survey 745 Prunus domestica (Plum) D virginia creeper on trunk 746 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.4"; not on survey 747 Hesperotropsis leylandii (Leyland cypress) E base at 2'=7.5"; not on survey 748 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.5"; not on survey 749 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.2"; not on survey 750 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.8"; not on survey 751 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4"; not on survey 752 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.3"; not on survey 753 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 754 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6"; not on survey 755 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.8"; not on survey 756 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 757 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.7"; not on survey 758 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.4"; not on survey 759 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.4"; not on survey 760 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4"; not on survey 761 Alnus rubra (Red alder) D Alnus rubra (Red alder) D

26 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 763 Alnus rubra (Red alder) D Prunus armeniaca (Apricot) D low lcr 765 Prunus armeniaca (Apricot) D low lcr; ivy on trunk; not on survey 766 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.3"; not on survey 767 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 768 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.5"; not on survey 769 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.2"; not on survey 770 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.3"; not on survey 771 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.7"; not on survey 772 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 773 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.5"; not on survey 774 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.5"; not on survey 775 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.8"; not on survey 776 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.8"; not on survey 777 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.5"; not on survey 778 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.6"; not on survey 779 Hesperotropsis leylandii (Leyland cypress) E base at 2'=6.4"; not on survey 780 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.8"; not on survey 781 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.5"; not on survey 782 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.5"; not on survey 783 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 784 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5.2"; not on survey 785 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.3"; not on survey 787 Hesperotropsis leylandii (Leyland cypress) E base at 2'=5"; not on survey 788 Hesperotropsis leylandii (Leyland cypress) E base at 2'=4.8"; not on survey 789 Pseudotsuga menziesii (Douglas-fir) E % impervious within dripline 790 Pseudotsuga menziesii (Douglas-fir) E topped at 20-ft for powerlines, 50% impervious in dripline 791 Betula pendula (European white birch) D included bark 792 Thuja plicata (Western red cedar) E codominate at 30' 793 Cunninghamia lanceolata (China fir) E Thuja plicata (Western red cedar) E ivy on trunk 795 Prunus domestica (Plum) D trunk wound at base with good response growth 796 Pinus monticola (Western white pine) E % of dripline is a house 797 Pseudotsuga menziesii (Douglas-fir) E limited root zone; topped at 20'; fungi on trunk 798 Hesperotropsis leylandii (Leyland cypress) E base at 2"=4.1"; not on survey 799 Cedrus deodara (Deodar cedar) E not on survey 800 Pseudotsuga menziesii (Douglas-fir) E Cedrus deodara (Deodar cedar) E suppressed canopy 802 Pseudotsuga menziesii (Douglas-fir) E self-corrected lean; low lcr 803 Acer macrophyllum (Bigleaf maple) D not on survey

27 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 804 Acer macrophyllum (Bigleaf maple) D in cavity at 10'; potential circling root; 10-degree lean to the south 805 Acer macrophyllum (Bigleaf maple) D Acer macrophyllum (Bigleaf maple) D not on survey; phototropic lean 807 Thuja plicata (Western red cedar) E Thuja plicata (Western red cedar) E suppressed canopy; pistol butt trunk 809 Acer macrophyllum (Bigleaf maple) D co-dominant; topped at 12'; not on survey 810 Thuja plicata (Western red cedar) E rooting branches that look like separate trees growing 811 Acer macrophyllum (Bigleaf maple) D trunk cavity 6-in in dia.; codominate at 15-ft 812 Acer macrophyllum (Bigleaf maple) D scaffold branch failure at 25-ft with good response growth 813 Acer macrophyllum (Bigleaf maple) D co-dominant at base; included bark; significant trunk wound 814 Alnus rubra (Red alder) D base at 2'=4.3"; not on survey 815 Prunus domestica (Plum) D poor pruning history; ivy on trunk; not on survey 816 Alnus rubra (Red alder) D not on survey 817 Pyrus domestica (Common pear) D base at 2'=5.8"; not on survey 818 Fraxinus latifolia (Oregon ash) D topped at 10-ft; not on survey 819 Styrax japonicus (Japanese snowbell) D additional DBH-8", 6" 820 Castanea dentata (American chestnut) D Acer macrophyllum (Bigleaf maple) D Thuja plicata (Western red cedar) E Acer macrophyllum (Bigleaf maple) D co-dominant at 6'; not on survey 824 Acer macrophyllum (Bigleaf maple) D additional DBH-7" 825 Crataegus monogyna (Common hawthorn) D not on survey 826 Prunus emarginata (Bitter cherry) D not on survey 827 Pinus nigra (Austrian pine) E co-dominant at 20'; included bark; low LCR 828 Pinus sylvestris (Scots pine) E Acer macrophyllum (Bigleaf maple) D co-dominant at 10'; topped at 15' for power lines 830 Betula pendula (European white birch) D Pinus sylvestris (Scots pine) E co-dominant at 15'; included bark; circling root 832 Arbutus menziesii (Pacific madrone) E Acer macrophyllum (Bigleaf maple) D pistol-butt trunk 842 Thuja plicata (Western red cedar) E Pseudotsuga menziesii (Douglas-fir) E se lean, self corected 844 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E topped at 10' 847 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E

28 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 853 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E suppressed 869 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E suppressed 871 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E suppressed 873 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E chlorotic foliage 885 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E chlorotic foliage 887 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E

29 MERCER ISLAND CHIU 4320 Island Crest Way, Mercer Island, WA parcel # Table Issued: 10/27/2017 Site Visit: 5/16/2017 and 8/24/2017 TAG # TREE NAME EV / DEC # STEMS COMB DBH (IN, ROUNDED) HEIGHT (FT) RADIUS (FT) CONDITION NOTES 895 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E sig trunk wound on ne side 973 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E trunk wound on ne side 976 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E trunk wounds 978 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E suppressed 990 Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E Hesperotropsis leylandii (Leyland cypress) E