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17-105489-Tree Retention Worksheet-04-02-2020-V13FORESTRY AND VEGETATION MANAGEMENT SPECIALISTS WFCI 3601943-1 723 FAX 3601943-4 1 28 1919 Yelm Hwy SE, Suite C Olympia, WA 98501 URBANIRURAL FORESTRY TREE APPRAISAL HAZARD TREE ANALYSIS RIGHT-OF-WAYS VEGETATION MANAGEMENT ENVIRONMENTAL STUDIES CONTRACT FORESTERS Member of International Society of Arboriculture and Society of American Foresters -Revised Tree and Vegetation Retention Plan - WOODBRIDGE CORPORATE PARK 32901 Weyerhaeuser Way S. Federal Way WA 98001 Prepared for: Federal Way Campus LLC Prepared by: Washington Forestry Consultants, Inc. Date of Report: February 18, 2020 Introduction The project proponent is planning to construct 3 commercial buildings on 135.6 acres in Federal Way WA. The proponent has retained WFCI to: •Evaluate and inventory all trees on the site pursuant to the requirements of Section 22-1568 of 1994 Federal Way City Code (1994 FWCC), in compliance with the Weyerhaeuser Company Concomitant Pre-Annexation Developer Agreement, dated August 23, 1994. •Make recommendations for retention of significant trees, along with required protection and cultural measures. •Complete the minimum stocking requirement calculations for the project. Observations Methodology The forest inventory was conducted using variable area plots on a systematic grid across the forested area of the project. To improve sample predictions of species, size, stand stocking and quality the forest stands were stratified into 11 forested cover types and 1 non-forest type (meadow). All species and all trees 6 inches DBH and larger were inventoried, however only trees 12 inches in diameter at breast height (DBH) or greater are reported as significant trees. In addition, red alder, black cottonwood, other Populus species, and bigleaf maple are not considered to be Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 2 significant trees by the 1994 ordinance. The forest inventory data was processed using SuperAce®, a forest inventory processing software program. The tree evaluation phase used methodology developed by Matheny and Clark (1998) in their text Trees and Development: A Technical Guide to Preservation of Trees during Land Development, published by the International Society of Arboriculture, Champaign, IL 1998. In all cases, the overall health of the tree was considered relative to its ability to add value to the new project. The potential for incorporation into the project design has been evaluated as well. Trees that are retained near new construction must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment and perform well in the landscape. Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be retained in areas where damage to people or property could occur. Site Description The project area consists of portions of 5 parcels totaling 135.6 acres. Topography is mostly flat to gently rolling, sloping slightly to the northeast into North Lake. The site is bordered to the north by commercial properties, to the west by Interstate 5, to the south by undeveloped forest and pasture, and to the east by undeveloped forest and North Lake. Many small wetlands occur sporadically on the west side of the project area near Interstate 5 and more contiguously on the east side near North Lake. There is a large commercial office building and associated parking lot in the central portion of the project area. An additional small office building exists on the eastern side of the property. Access to the site is by Weyerhaeuser Way S. Numerous trails and small roads traverse the ownership. Soil Depth and Productivity According to the USDA Natural Resource Conservation Service Web Soil Survey, there is one soil type in the project area - the Alderwood gravelly sandy loam. The Alderwood gravelly sandy is a moderately deep, moderately well drained soil found on glacial till plains. It is formed in ablation till overlying basal till. A weakly cemented hardpan is at a depth of 20 to 40 inches. Permeability is moderately rapid above the hardpan and very slow in the pan. Available water capacity is low. Effective rooting depth is 20-40 inches. A perched seasonal high water table is at a depth of 18-36 inches from November to March. The potential for windthrow of trees is ‘moderate’ under normal conditions. New trees require irrigation for establishment. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 3 In areas where grading brings the Alderwood hardpan nearer to the surface, the hardpan must be fractured under new trees to provide soil volume for root development and to improve drainage around the tree. Figure 1. Soils Map of Woodbridge Corporate Park Project Area Project Area Boundary Ag - Alderwood gravelly sandy loam - 98.4% Existing Tree Conditions There are 12 forest cover types for the purposes of description. The location and extent of each cover type is illustrated on the aerial photograph in Attachment 1. Forest Cover Type I. – This 30.65 acre type includes the developed portion of the project area near the existing large office building. The 9.5 acre treed portion of this cover type includes the forested islands in the parking area. Major tree species include western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii), and bigleaf maple (Acer macrophyllum). Many planted ornamental tree species also occur in this cover type, including Norway maple (Acer platanoides), sycamore maple (Acer pseudoplatanus), N Ag Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 4 Atlas cedar (Cedrus atlantica), deodar cedar (Cedrus deodara), katsura (Cercidiphyllum japonicum), Turkish filbert (Corylus maxima), European beech (Fagus sylvatica), western larch (Larix occidentalis), sweet-gum (Liquidambar styraciflua), wild cherry (Prunus avium), flowering cherry (Prunus serrulata), white oak (Quercus alba), cascara (Rhamnus purshiana), giant sequoia (Sequoiadendron giganteum), lodgepole pine (Pinus contorta), western white pine (Pinus monticola), Leyland cypress (Cupressocyparis x. leylandii), and European linden (Tilia platyphyllos). Tree size ranges from 12 to 57 inches DBH. There are approximately 87 Trees per Acre (TPA), or 810 total significant trees in the 9.5 forested acres of the total 30.65-acre cover type. Tree condition ranges from ‘Poor’ to ‘Good,’ with the vast majority (98%) of trees described as healthy (‘Fair’ condition or better). Photo 1. View of trees in Cover Type I Understory vegetation consists of mostly native plants and some non-native, invasive species. Native species include vine maple (Acer circinatum), western hazel (Corylus cornuta), Indian- plum (Oemleria cerasiformis), salal (Gaultheria shallon), thimbleberry (Rubus parviflorus), trailing blackberry (Rubus ursinus), snowberry (Symphoricarpos alba), prostrate Oregon-grape (Mahonia nervosa), sword fern (Polystichum munitum), and bracken fern (Pteridium aquilinum). Invasive plants include English ivy (Hedera helix), blackberry (Rubus armeniacus), grasses, and broadleaved weeds. This community of understory vegetation is common throughout the project area. Table 1. Summary of Significant and Other Trees in Cover Type I Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 12 - 38 ‘Fair’ - ‘Good’ 18 167 Western Redcedar 12 - 57 ‘Poor’ - ‘Good’ 27 242 Bigleaf Maple* 32 - 53 ‘Poor’ - ‘Fair’ <1 0 Other Conifer 15 - 28 ‘Fair’ - ‘Good’ 8 80 Other Hardwood 12 - 20 ‘Fair’ - ‘Good’ 33 316 Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 5 Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Total 12 - 57 ‘Poor’ - ‘Good’ 87 805 *Not Considered Significant under 1994 Definition Forest Cover Type II. -- Type II is a mature stand of Douglas-fir with some bigleaf maple, red alder (Alnus rubra), and planted ornamental trees. Tree size ranges from 12 to 46 in. DBH. There are 80 trees per acre and 451 significant trees across the 8.25-acre cover type. Tree condition ranges from ‘Dead’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Photo 2. View of trees in Cover Type II Understory vegetation is similar to Cover Type I, but denser and more contiguous. Elderberry (Sambucus racemosa) and red mountain huckleberry (Vaccinium parvifolium) are also present. Table 2. Summary of Trees in Cover Type II Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 15 - 46 ‘Fair’ - ‘Good’ 55 451 Red Alder* 12 - 15 ‘Poor’ 13 0 Bigleaf Maple* 12 - 17 ‘Fair’ 4 0 Other Conifer 12 - 24 ‘Poor’ 8 0 Total 12 - 46 ‘Poor’ - ‘Good’ 80 451 *Not Considered Significant under 1994 Definition Cover Type III. -- Type III is a low-density, mixed stand of mostly deciduous trees including mostly red alder and black cottonwood. Some large Douglas-fir and western redcedar trees also occur in this cover type, but are widely scattered. Tree size ranges from 15 to 48 inches DBH. There are 30 trees per acre and 35 significant trees over the 7.5-acre cover type. Tree condition ranges from ‘Dead’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Table 3. Summary of Trees in Cover Type III Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 28 - 46 ‘Fair’ - ‘Good’ 5 35 Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 6 Red Alder* 15 - 23 ‘Poor’ 23 0 Black Cottonwood* 20 - 48 ‘Fair’ <1 0 Western Redcedar 24 - 40 ‘Poor’ 1 0 Total 15 - 48 ‘Poor’ - ‘Good’ 30 35 *Not Considered Significant under 1994 Definition Photo 3. View of trees in Cover Type III Understory vegetation is very dense and consists of mostly native plants and some non-native, invasive species. Native species include vine maple, western hazel, Indian-plum, salal, trailing blackberry, snowberry, prostrate Oregon-grape, sword fern, and bracken fern. Invasive plants include English ivy, blackberry, grasses, and broadleaved weeds. Forest Cover Type IV. -- Type IV is a dense plantation of predominantly Douglas-fir trees with a lesser numbers of deciduous trees and exotic conifers such as Norway spruce (Picea abies). Tree size ranges from 12 to 69 in. DBH, but are most commonly in the 14 to 16 inch DBH range. There are 162 trees per acre and 1,956 healthy, significant trees over the 13.5-acre cover type. Tree condition ranges from ‘Dead’ to ‘Good,’ with most trees (90%) described as being in ‘Fair’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 7 Table 4. Summary of Trees in Cover Type IV Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 12 - 36 ‘Fair’ - ‘Good’ 149 1,785 Other Conifer 12 - 13 ‘Poor’ 7 98 Black Cottonwood* 69 ‘Fair’ <1 0 Other Hardwood 24 - 40 ‘Poor’ 5 73 Total 12 - 69 ‘Poor’ - ‘Good’ 162 1,956 *Not Considered Significant under 1994 Definition Photo 4. View of trees in Cover Type IV Understory vegetation is less dense than other cover types and consists of mostly native plants. Species include vine maple, woods rose (Rosa woodsia), Indian-plum, salal, trailing blackberry, snowberry, prostrate Oregon-grape, sword fern, and bracken fern. Forest Cover Type V. -- Type V is a mixed stand of mostly native and planted deciduous trees and conifers including Douglas-fir, black cottonwood, European linden, European birch (Betula pendula), and western larch (Larix occidentalis). Tree size ranges from 13 to 29 inches DBH. There are 129 trees per acre in this cover type and 425 significant trees over the 4.25-acre cover type. Tree condition ranges from ‘Poor’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 8 Photo 5. View of trees in Cover Type V Understory vegetation consists of mostly native plants and some non-native, invasive species. Native species include Indian-plum, salal, trailing blackberry, prostrate Oregon-grape, sword fern, and bracken fern. Invasive plants include English ivy, and blackberry. Table 5. Summary of Trees in Cover Type V Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 18 - 19 ‘Fair’ - ‘Good’ 21 91 Other Conifer 12 - 13 ‘Poor’ 51 108 Black Cottonwood* 29 ‘Fair’ 4 0 Other Hardwood 24 - 40 ‘Poor’ 53 226 Total 12 - 40 ‘Poor’ - ‘Good’ 129 425 *Not Considered Significant under 1994 Definition Forest Cover Type VI. -- Type VI is a high-density plantation of small deciduous trees with a few conifers mixed in. An exotic species of ash (Fraxinus spp.) is dominant. Scattered Douglas-fir, giant Sequoia, Nordmann fir (Abies nordmaniana) and western larch trees also occur. Tree size ranges from 12 to 42 inches DBH. There are 162 trees per acre and 536 significant trees over the 6.5-acre cover type. Tree condition ranges from ‘Dead’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 9 Photo 6. View of trees in Cover Type VI Understory vegetation is very dense and consists mostly of invasive blackberry. Occasional native species include Indian-plum, salal, trailing blackberry, prostrate Oregon-grape, elderberry, sword fern, and bracken fern. Table 6. Summary of Trees in Cover Type VI Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Other Conifer 12 - 13 Good 7 45 Ash 24 - 42 ‘Poor’ 75 490 Total 12 - 42 ‘Poor’ - ‘Good’ 82 535 Forest Cover Type VII. -- Type VII is a poorly stocked stand of low-quality deciduous trees with a few conifers intermixed. Species include mostly black cottonwood, bigleaf maple, and white poplar (Populus alba), with a few small, scattered western redcedars, and Douglas-firs, most of which are not significant. Tree size is relatively large and ranges from 12 to 56 inches DBH. There are 27 trees per acre and 106 significant trees over the 10.8-acre cover type. Tree condition ranges from ‘Dead’ to ‘Good,’ with most trees described as being in ‘Poor’ condition or worse. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 10 Photo 7. View of trees in Cover Type VII – type is to the right. Understory vegetation consists of equal parts native plants and non-native, invasive species. Native species include salmonberry (Rubus spectabilis), western hazel, Indian-plum, salal, trailing blackberry, snowberry, prostrate Oregon-grape, sword fern, and bracken fern. Invasive plants include English ivy, blackberry, grasses, and broadleaved weeds. Table 7. Summary of Trees in Cover Type VII Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 14 - 18 ‘Dead’ - ‘Fair’ 7 77 Bigleaf Maple* 12 - 13 ‘Poor’ 1 0 Poplar* 18 - 56 ‘Fair’ 16 0 Western Redcedar 12 - 26 ‘Poor’ - ‘Good’ 3 29 Total 12 - 56 ‘Dead’ - ‘Good’ 27 106 *Not Considered Significant under 1994 Definition Forest Cover Type VIII. -- Type VIII is a managed stand of mature western redcedar trees. A few red alder, Douglas-fir, and western hemlock (Tsuga heterophylla) can also be found in this type. Ornamental trees are also present along Weyerhaeuser Way S., including Norway spruce, and golden-rain tree (Laburnum vossii). Tree size is relatively large and ranges from 12 to 62 inches DBH. There are 49 trees per acre and 360 healthy, significant trees over the 9.5-acre cover type. Tree condition ranges from ‘Very Poor ’ to ‘Good,’ with most trees described as being in ‘Fair ’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 11 Photo 8. View of trees in Cover Type VIII Understory vegetation is very dense and consists of mostly native plants. Species include western hazel, Indian-plum, salal, trailing blackberry, prostrate Oregon-grape, sword fern, and bracken fern. Other plants include blackberry and foxglove (Digitalis purpurea). Table 8. Summary of Trees in Cover Type VIII Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 31 - 38 ‘Good’ 5 48 Red Alder* 12 - 13 ‘Poor’ 6 0 Western Hemlock 18 - 56 ‘Poor’ - ‘Good’ 11 92 Western Redcedar 12 - 26 ‘Poor’ 27 220 Total 12 - 56 ‘Dead’ - ‘Good’ 49 360 *Not Considered Significant under 1994 Definition Forest Cover Type IX. -- Type IX is a mixed stand of mature black cottonwood, red alder, and western redcedar. Some Douglas-fir, Oregon ash (Fraxinus latifolia) and bigleaf maple trees occur in the intermediate crown class. Tree size is relatively large and ranges from 12 to 56 inches DBH. There are 19 trees per acre and 16 healthy, significant trees over the 3.5-acre cover type. Tree condition ranges from ‘Very Poor’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 12 Photo 9. View of trees in Cover Type IX Understory vegetation is very dense and consists of mostly native plants and some non-native, invasive species. Native species include salmonberry, vine maple, cascara, western hazel, Indian- plum, salal, trailing blackberry, prostrate Oregon-grape, sword fern, and bracken fern. Invasive plants include English ivy, blackberry, grasses, and broadleaved weeds. Table 9. Summary of Trees in Cover Type IX Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 31 - 38 ‘Good’ 2 7 Red Alder* 12 - 13 ‘Poor’ 13 0 Black Cottonwood* 18 - 56 ‘Poor’ - ‘Good’ 1 0 Western Redcedar 12 - 26 ‘Fair’ 3 9 Total 12 - 56 ‘Poor’ - ‘Good’ 19 16 *Not Considered Significant under 1994 Definition Forest Cover Type X. -- Type X is a mature stand of Douglas-fir and bigleaf maple with some western redcedar, western hemlock and red alder in the understory. Tree size ranges from 12 to 57 inches DBH. There are 37 trees per acre and 440 healthy, significant trees over the 10.25-acre cover type. Tree condition ranges from ‘Poor’ to ‘Good,’ with most trees described as being in ‘Fair’ condition or better. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 13 Photo 10. View of trees in Cover Type X Understory vegetation consists of mostly native plants and some non-native, invasive species. Native species include vine maple, western hazel, Indian-plum, salal, trailing blackberry, snowberry, prostrate Oregon-grape, sword fern, and bracken fern. Invasive plants include English ivy, blackberry, English holly (Ilex aquifolium), grasses, and broadleaved weeds. Table 10. Summary of Trees in Cover Type X Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 12 - 52 ‘Fair’ - ‘Good’ 8 82 Western Redcedar 12 - 57 ‘Fair’ - ‘Good’ 15 151 Bigleaf Maple* 16 - 28 ‘Poor’ - ‘Fair’ 6 0 Red Alder* 15 - 28 ‘Fair’ - ‘Good’ 7 0 Black Cottonwood* 12 - 20 ‘Fair’ - ‘Good’ 1 0 Total 12 - 57 ‘Poor’ - ‘Good’ 37 440 *Not Considered Significant under 1994 Definition Forest Cover Type XI. -- Type XI is a high-density stand of low-quality, native deciduous trees including Oregon ash and black cottonwood. Some Douglas-fir trees also occur in this cover type, but are widely scattered and mostly in ‘Poor’ condition due to suppression. Tree size is generally small and ranges from 8 to 26 inches DBH. There are 168 trees per acre with no significant trees over the 6.5-acre cover type. Tree condition ranges from ‘Dead’ to ‘Fair,’ with most trees described as being in ‘Poor’ condition or worse. Table 11. Summary of Trees in Cover Type XI Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 14 - 26 ‘Poor’ 3 0 Black Cottonwood* 12 - 20 ‘Dead’ - ‘Fair’ 114 0 Ash 8 - 9 ‘Poor’ - ‘Fair’ 51 0 Total 8 - 26 ‘Dead’ - ‘Fair’ 168 0 *Not Considered Significant under 1994 Definition Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 14 Phot o 11. View of trees in Cover Type XI Understory vegetation is dense and consists of mostly native plants, tree saplings, and some non- native, invasive species. Native species include salmonberry, western hazel, Indian-plum, salal, trailing blackberry, snowberry (Symphoricarpos alba), prostrate Oregon-grape, sword fern, and bracken fern (Pteridium aquilinum). Invasive plants include English ivy (Hedera helix), blackberry (Rubus armeniacus), grasses, and broadleaved weeds. Forest Cover Type XII. -- Type XII is an open field on the southern end of the project area. Aside from a few deciduous trees in a wetland area on the very southern end, there are no trees in this cover type. Vegetation consists mostly of grass. Summary of All Cover Types A total of about 99.1 acres of the 135.6-acre project area are forested by 12 distinct forest cover types. The following table summarizes all cover types and significant trees in the Woodbridge Corporate Park project area. Table 12. Summary of all Cover Types in the Woodbridge Corporate Park Project Area Species DBH Range (in.) Condition Range Total Trees Per Acre Total # Healthy Significant Trees Douglas-fir 12 - 52 ‘Dead’ - ‘Good’ 29.67 2,729 Western Redcedar 12 - 57 ‘Poor’ - ‘Good’ 8.04 658 Western Hemlock 18 - 56 ‘Poor’ - ‘Good’ 0.98 92 Oregon Ash 8 - 10 ‘Poor’ - ‘Fair’ 3.17 0 Other Conifer 12 - 24 ‘Poor’ - ‘Good’ 4.85 81 Other Hardwood** 12 - 40 ‘Poor’ - ‘Good’ 10.51 1,105 Bigleaf Maple* 12 - 53 ‘Poor’ - ‘Good’ 2.23 0 Red Alder* 12 - 28 ‘Very Poor’ - ‘Good’ 5.10 0 Black Cottonwood* 12 - 69 ‘Very Poor’ - ‘Good’ 9.90 0 Total 8 - 69 ‘Dead’ - ‘Good’ 74.45 4,665 *Not Considered Significant under 1994 Definition **Includes non-native Ash Trees Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 15 Discussion The 1994 Federal Way City Code requires 25% of the significant trees to be retained on commercial projects. Current site plans leave much of Cover Types X, XI, XII and portions of Cover Type IV undeveloped. The following is a summary of our tree retention calculations. Total # of Significant Trees in Buildable Area of Project 4,665 Required Tree Retention (25% x 4,665) 1,166 Healthy Significant Perimeter Landscape Trees 584 Healthy Significant Trees in Managed Forest (1,096 x 2) 2,192 Total Healthy Significant Trees Retained on Site 2,776 Surplus of Tree Retention Requirement +1,610 The 1994 Federal Way City Code states that significant trees not located in the perimeter landscaping may be credited as two trees for the purpose of retention requirements. This means that the 1,096 interior trees count as 2,192 trees when calculating tree retention. By retaining 1,680 healthy significant trees, which count as 2,776 healthy (60%) significant trees in the project area, this plan exceeds the 25% minimum retention requirement described in Federal Way City Code (1994) by 35%. An additional 382 healthy trees, smaller than 12”, are also being retained. Tree Protection Measures Trees that are saved must be protected during construction by temporary chain-link fencing on driven posts (Attachment 4), located at the edge of the critical root zone for the protected tract, or individual trees if they occur. The individual critical root zones are 5 feet outside the dripline of all edge trees unless otherwise delineated by WFCI. There should be no equipment activity within the critical root zone. No irrigation lines, trenches, or other utilities should be installed within the critical root zone. If roots are encountered outside the critical root zone, they should be cut cleanly with a saw and covered immediately with moist soil. Noxious vegetation within the critical root zone should be removed by hand. If a proposed save tree must be impacted by grading or fills, then the tree should be re-evaluated by WFCI to determine if the tree can be saved and mitigating measures, or if the tree should be removed. Pruning and Thinning All individual trees to be saved near or within developed areas should have their crowns raised to provide a minimum of 8 feet of ground clearance over sidewalks and landscape areas, 15 feet over streets, and at least 10 feet of building clearance. Trees in protected forest stands do not require pruning. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 16 All pruning should be done according to the ANSI A300 standards for proper pruning, and be completed by an International Society of Arboriculture Certified Arborist®, or be supervised by a Certified Arborist®. The ANSI Z133.1 (2000) American National Standard - for Arboricultural Operations - Pruning, Repairing, Maintaining, and Removing Trees, and Cutting Brush – Safety Requirements should be observed by all tree workers. Portions of the tree tracts are very dense and would benefit from selective thinning to release higher quality dominant and codominant trees. If this were to be done, then WFCI would need to develop the stand prescriptions and mark the stand for the selective thinning work. There are areas that are stagnant due to high stocking. Conclusions and Timeline for Activity The following is a list of recommended tree protection activities and the proposed timing: 1. Prepare the final tree retention plan map showing tracts to be protected and the locations of tree protection fencing. 2. Mark the clearing limits of the project with stakes and flagging. The marking should be heavy so that one can see from flag to flag or stake to stake. 3. Conduct a pre-job conference with WFCI. We will inspect the tree clearing limits and mark hazard trees and trees that would be damaged by grading on the edges. 4. Complete logging. WFCI will inspect the new stand edges after cutting, but before the logger leaves the site. We will mark any additional trees that require removal. 5. Complete the logging. 6. Prune all edge trees that require clearances or hazard pruning. 7. Install tree protection fences - Contact WFCI to inspect the installed tree protection fences. 8. Complete land clearing. Do not remove any stumps within 10 ft. of a save tree. WFCI should inspect these stumps to determine if it can be removed using an excavator or requires grinding. 9. Complete grading and construct project. 10. Maintain the tree protection fences throughout grading and construction. 11. WFCI should inspect all tree tract edges after grading to identify any trees that might have been impacted by clearing and grading. The goal is an edge of green, healthy, windfirm trees. 12. If any unplanned construction activity will impact a ‘save’ tree, contact WFCI prior to the impact. WFCI can assess the proposed impact and recommend cultural care, mitigation, or removal. 13. Conduct an annual tree evaluation to determine short-and long-term effects of site changes on protected trees. Provide additional cultural care as needed. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 17 Summary Federal Way City Code (1994) requires that 25% of the significant trees in the Woodbridge Corporate Park will need to be retained during site development. A total of 1,680 significant trees, which count as 2,192 (60%) will be retained in perimeter tree tracts and managed forest areas. By counting healthy significant trees in managed areas within the interior portion of the site as 2 trees, the minimum 25% retention requirement is exceeded by 1,610 trees. Please give us a call if you have further questions. Respectfully submitted, Washington Forestry Consultants, Inc. Galen M. Wright, ACF, ASCA Joshua Sharpes ISA Bd. Certified Master Arborist PN-129BU ISA Certified Arborist/ Certified Forester No. 44 Municipal Specialist, PN-5939AM ISA Tree Risk Assessor Qualified ASCA Tree and Plant Appraisal Qualified Other Contributors: Riley Stark - Professional Forester, ISA Board Certified Master Arborist, Municipal Specialist #PN-7780 Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 18 Attachment 1. Aerial Photo of Woodbridge Corporate Park Project Area with Extent of Forest Cover Types Indicated (2017 King County iMap) Property Boundary Forest Cover Type Line XII N IV III II IX VI VII VII XI X VIII I V Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 19 Attachment 2. Woodbridge Site Plan N Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 20 Attachment 3. Stand Summary Summaries for Forested Acres of Project –Species by Diameter Class and Stocking (Trees/Acre). (3 pages attached) Acres Project 105.10 WDBRIDGE Time: 2:59:24PM Date:6/17/2019 Page 1Stand Table Summary PSTNDSUM T21N R04E S16 Ty0001 THRU T21N R04E S16 Ty0012 TC Federal Way Campus LLC Grown Year: T o t a l s Sample Trees Tons S T AcreSpc MBFCunits Net Bd.Ft. Acre Net Cu.Ft.Tons/ Acre Average Log Net Bd.Ft. Net Cu.Ft. Logs Acre BA/ Acre Trees/ Acre Av Tot Ht16'DBH FF BA/ 16 43 .402 .56 1 24BM 17 62 .332 .52 1 28BM 21 42 .233 .56 1 22BM 24 82 .783 2.46 2 49 BM 28 88 .288 1.23 1 53BM 32 80 .046 .26 1 38BM 38 43 .130 1.03 1 20BM 53 79 .017 .26 1 36BM BM 9 66 37 2.232Totals 6.88 6 98 3.150 .62 1 17CW 12 98 1.575 1.24 2 17CW 13 98 .671 .62 1 17CW 14 98 1.157 1.24 2 17CW 20 62 .283 .62 1 27CW 22 74 .602 1.59 2 34CW 24 76 .654 2.06 2 35CW 26 62 .152 .56 1 26CW 29 78 .400 1.84 2 37CW 32 80 .496 2.77 4 40CW 33 42 .173 1.03 1 20CW 36 82 .079 .56 1 42CW 37 88 .165 1.23 1 52CW 39 73 .075 .62 1 31CW 48 90 .057 .71 1 62CW 50 88 .090 1.23 1 51CW 56 86 .060 1.03 1 46CW 59 90 .035 .67 1 62CW 69 62 .033 .86 1 25CW CW 27 90 23 9.908Totals 21.07 11 98 1.689 1.11 2 17DF 12 54 1.090 .86 1 26DF 13 78 10.499 9.68 12 42DF 14 63 3.204 3.43 4 28DF 15 84 .426 .52 1 60DF 16 74 2.712 3.79 5 43 DF 17 67 .543 .86 1 28DF 18 74 1.865 3.30 6 37DF 19 84 1.073 2.11 4 56DF 20 87 .480 1.05 2 71DF 21 88 .218 .52 1 73DF 22 88 .198 .52 1 78 DF 23 88 .363 1.05 2 78DF 24 86 .345 1.08 2 66DF 25 84 .152 .52 2 52DF 26 81 .946 3.49 5 63DF 28 88 .508 2.17 3 73DF 29 88 .170 .78 2 78 DF 30 88 .107 .52 1 86DF 31 88 .414 2.17 4 88DF 32 89 .202 1.13 2 93DF 33 88 .088 .52 1 102DF 34 89 .278 1.75 2 90DF Acres Project 105.10 WDBRIDGE Time: 2:59:24PM Date:6/17/2019 Page 2Stand Table Summary PSTNDSUM T21N R04E S16 Ty0001 THRU T21N R04E S16 Ty0012 TC Federal Way Campus LLC Grown Year: T o t a l s Sample Trees Tons S T AcreSpc MBFCunits Net Bd.Ft. Acre Net Cu.Ft.Tons/ Acre Average Log Net Bd.Ft. Net Cu.Ft. Logs Acre BA/ Acre Trees/ Acre Av Tot Ht16'DBH FF BA/ 36 88 .158 1.11 2 79DF 37 87 .166 1.24 2 76DF 38 88 .109 .86 2 66DF 40 89 .418 3.65 4 100 DF 41 90 .191 1.75 2 106DF 43 89 .244 2.46 2 106DF 44 89 .068 .71 1 84DF 45 90 .111 1.23 1 116DF 46 89 .045 .52 1 100DF 47 89 .102 1.23 1 100 DF 52 90 .083 1.23 1 104DF DF 85 78 47 29.268Totals 58.94 8 99 1.772 .62 1 17OA 9 98 1.400 .62 1 17OA OA 2 99 17 3.172Totals 1.24 12 92 2.726 2.14 3 22OC 13 64 1.209 1.11 2 23 OC 15 67 .421 .52 2 30OC 23 78 .429 1.24 1 38OC 28 69 .060 .26 1 27OC OC 9 81 24 4.845Totals 5.27 9 98 .585 .26 1 17OH 11 31 .391 .26 1 26OH 12 99 .329 .26 1 17OH 13 68 2.500 2.30 3 27OH 14 59 3.312 3.54 4 29OH 15 72 2.337 2.87 5 24OH 17 62 .513 .81 1 28OH 18 70 .292 .52 2 20OH 19 73 .131 .26 1 33OH 20 43 .118 .26 1 22OH OH 20 67 26 10.508Totals 11.33 13 73 .568 .52 1 36RA 14 88 .564 .60 1 60RA 15 60 2.468 3.03 4 31RA 16 62 .511 .71 1 28 RA 17 78 .423 .67 1 40RA 20 62 .327 .71 1 27RA 23 73 .247 .71 1 32RA RA 10 67 35 5.108Totals 6.96 10 99 .474 .26 1 17RC 12 85 1.896 1.49 2 21RC 14 82 .242 .26 1 18RC 16 81 .185 .26 1 18RC 17 82 .164 .26 1 21RC 19 81 .743 1.46 3 36RC 22 80 .228 .60 1 44RC 23 82 .090 .26 1 26RC 24 81 .082 .26 1 44RC Acres Project 105.10 WDBRIDGE Time: 2:59:24PM Date:6/17/2019 Page 3Stand Table Summary PSTNDSUM T21N R04E S16 Ty0001 THRU T21N R04E S16 Ty0012 TC Federal Way Campus LLC Grown Year: T o t a l s Sample Trees Tons S T AcreSpc MBFCunits Net Bd.Ft. Acre Net Cu.Ft.Tons/ Acre Average Log Net Bd.Ft. Net Cu.Ft. Logs Acre BA/ Acre Trees/ Acre Av Tot Ht16'DBH FF BA/ 25 80 .722 2.46 2 61RC 26 80 .722 2.66 6 45RC 27 81 .065 .26 1 37RC 28 80 .141 .60 1 54 RC 31 81 .214 1.12 3 39RC 32 81 .262 1.46 3 56RC 34 80 .191 1.21 2 51RC 36 81 .037 .26 1 39RC 37 81 .115 .86 2 60RC 38 80 .194 1.53 3 62 RC 40 81 .220 1.92 3 58RC 41 80 .089 .82 2 57RC 42 81 .152 1.46 3 53RC 43 81 .148 1.49 2 59RC 44 80 .174 1.83 2 69RC 45 80 .109 1.21 2 69 RC 46 80 .052 .60 1 63RC 47 80 .102 1.23 1 73RC 49 81 .046 .60 1 63RC 52 80 .041 .60 1 57RC 53 80 .080 1.23 1 62RC 54 81 .016 .26 1 43 RC 57 80 .015 .26 1 41RC 62 81 .029 .60 1 67RC RC 58 83 40 8.038Totals 31.64 15 70 .491 .60 1 28WH 17 84 .382 .60 1 45WH 33 88 .101 .60 1 53WH WH 3 77 37 .975Totals 1.81 Totals 223 79 36 145.14 74.053 Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 21 Attachment 4. Tree Protection Fence Detail – Locations to be Determined Temporary Chain Link Fence on Driven Posts Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 22 Attachment 5. Description of Tree Evaluation Methodology The evaluation of the tree condition on this site included the visual assessment of: 1. Live-crown ratio, 2. Lateral and terminal branch growth rates, 3. Presence of dieback in minor and major scaffold branches and twigs, 4. Foliage color, 5. Stem soundness and other structural defects, 6. Visual root collar examination, 7. Presence of insect or disease problems. 8. Windfirmness: if tree removal will expose this tree to failure. In cases where signs of internal defect or disease were suspected, a core sample was taken to look for stain, decay, and diameter growth rates. Also, root collars were exposed to look for the presence of root disease. In all cases, the overall appearance of the tree was considered relative to its ability to add value to either an individual lot or the entire subdivision. Also, the scale of the tree and its proximity to both proposed and existing houses was considered. Lastly, the potential for incorporation into the project design is evaluated, as well as potential site plan modifications that may allow otherwise removed tree(s) to be both saved and protected in the development. Trees that are preserved in a development must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment, and perform well in the landscape. Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be preserved in areas where damage to people or property could occur. Trees that have developed in a forest stand are adapted to the close, dense conditions found in such stands. When surrounding trees are removed during clearing and grading, the remaining trees are exposed to extremes in wind, temperature, solar radiation, which causes sunscald, and other influences. Young, vigorous trees with well-developed crowns are best able to adapt to these changing site conditions. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 23 Attachment 6. Glossary of Forestry and Arboricultural Terminology DBH: Diameter at Breast Height (measured 4.5 ft. above the ground line on the high side of the tree). In Edgewood, diameter is measured at 3 ft. above the groundline. Live Crown Ratio: Ratio of live foliage on the stem of the tree. Example: A 100’ tall tree with 40 feet of live crown would have a 40% live crown ratio. Conifers with less than 30% live crown ratio are generally not considered to be long-term trees in forestry. Crown: Portion of a trees stem covered by live foliage. Crown Position: Position of the crown with respect to other trees in the stand. Dominant Crown Position: Receives light from above and from the sides. Codominant Crown Position: Receives light from above and some from the sides. Intermediate Crown Position: Receives little light from above and none from the sides. Trees tend to be slender with poor live crown ratios. Suppressed Crown Position: Receives no light from above and none from the sides. Trees tend to be slender with poor live crown ratios. Woodbridge Corporate Park - Tree and Vegetation Retention Plan Washington Forestry Consultants, Inc. Page 24 Attachment 7. Assumptions and Limiting Conditions 1) Any legal description provided to the Washington Forestry Consultants, Inc. is assumed to be correct. Any titles and ownership's to any property are assumed to be good and marketable. No responsibility is assumed for matters legal in character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management. 2) It is assumed that any property is not in violation of any applicable codes, ordinances, statutes, or other governmental regulations, unless otherwise stated. 3) Care has been taken to obtain all information from reliable sources. All data has been verified insofar as possible; however, Washington Forestry Consultants, Inc. can neither guarantee nor be responsible for the accuracy of information. 4) Washington Forestry Consultants, Inc. shall not be required to give testimony or to attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services as described in the fee schedule and contract of engagement. 5) Loss or alteration of any part of this report invalidated the entire report. 6) Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. 7) Neither all or any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. -- particularly as to value conclusions, identity of Washington Forestry Consultants, Inc., or any reference to any professional society or to any initialed designation conferred upon Washington Forestry Consultants, Inc. as stated in its qualifications. 8) This report and any values expressed herein represent the opinion of Washington Forestry Consultants, Inc., and the fee is in no way contingent upon the reporting of a specified value, a stipulated result, the occurrence neither of a subsequent event, nor upon any finding in to reported. 9) Sketches, diagrams, graphs, and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys. 10) Unless expressed otherwise: 1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and 2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the tree or other plant or property in question may not arise in the future. Note: Even healthy trees can fail under normal or storm conditions. The only way to eliminate all risk is to remove all trees within reach of all targets. Annual monitoring by an ISA Certified Arborist or Certified Forester will reduce the potential of tree failures. It is impossible to predict with certainty that a tree will stand or fail, or the timing of the failure. It is considered an ‘Act of God’ when a tree fails, unless it is directly felled or pushed over by man’s actions.