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23-106053 - TPP -12-27-2023WASHINGTON FORESTRY CONSULTANTS, INC. FORESTRY AND VEGETATION MANAGEMENT SPECIALISTS W F C I O: 360/943-1723 C: 360/561-4407 9136 Yelm Hwy SE Olympia, WA 98513 URBAN/RURAL FORESTRY • TREE APPRAISAL • TREE RISK ASSESSMENT RIGHT-OF-WAYS • VEGETATION MANAGEMENT • FOREST/TREE MGT. PLANS • EXPERT TESTIMONY Member of International Society of Arboriculture and Society of American Foresters -Preliminary Tree Conservation Plan - FEDERAL WAY OPERATIONS & MAINENANCE FACILITY 28th Avenue South Federal Way, WA Prepared for: AHBL, Inc. Prepared by: Washington Forestry Consultants, Inc. Date of Report: October 20, 2023 Introduction The project proponent is planning to develop 14 parcels totaling 13.87-acres in Federal Way, Washington. The proponent has retained WFCI to: •Complete and inventory and assessment of the trees on the site. •Make recommendations for retention, removal, protection, and/or cultural care. •Complete tree retention and replacement calculations according to Federal Way Municipal Code 19.120.130. •Prepare a tree protection plan. Observations Methodology WFCI has evaluated significant trees 6 inches diameter at breast height (DBH) and larger in the proposed project area and assessed their potential to be incorporated into the new project. The entire site was 100% inventoried using a dot tally to count the number of trees within the project area. Trees were assessed as healthy or unhealthy trees. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 2 Site Description The project area includes 14 parcels totaling 13.87-acres. Parcel numbers of the project are 0921049315, 0921049314, 0921049313, 0921049075, 0921049084, 0921049239, 0921049095, 0921049115, 0921049085, 0921049170, 0921049009, 0921049250, 0921049198, and 0921049026. There are homes, outbuildings, maintenance facilities, paved areas, and other improvements located on the project site. The topography is generally flat north to south and moderately sloping to the east down to I-5. The project area is bordered by I-5 to the east, an apartment complex to the south, 28th Avenue South to the west, and single-family homes to the north. Soil Depth and Productivity According to the Natural Resource Soil Conservation Survey the soil types on the site are two variants of the Alderwood gravelly sandy loam. Figure 1. Soil Map of Federal Way Operations and Maintenance Facility Site. AgB – Alderwood gravelly sandy loam 0 – 8% AgC – Alderwood gravelly sandy loam 8 – 15% Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 3 The two soil types are the Alderwood gravelly sandy loam, 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. In areas where grading brings the 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. Tree Conditions There are three forest cover types on the site for the purposes of description. The cover type boundary delineation is shown on the aerial photo in Attachment 1. Type I. – This cover type is the largest stand of trees on the project site. It is a native stand of bigleaf maple (Acer macrophyllum), black cottonwood (Populus trichocarpa), Douglas-fir (Pseudotsuga menziesii), western redcedar (Thuja plicata), red alder (Alnus rubra), western hemlock (Tsuga heterophylla), Pacific madrone (Arbutus menziesii), and Scouler’s willow (Salix scouleriana). The inventory found 268 trees growing in this type. The diameter range for the trees is from 6 to 50 inches DBH. Seventy-two percent of the trees are in ‘Fair’ or better condition. The type is dominated by red alder and bigleaf maples that are overmature with significant decay and previous top failures. The best trees to retain in this type are the western redcedar and Douglas- fir. Table 1. Summary of Trees in Cover Type I. Species DBH Range (in.) Condition Range # of Healthy Significant Trees # of Unhealthy Significant Trees Total # of Trees Bigleaf Maple 6 – 50 Very Poor – Fair 82 18 100 Black Cottonwood 28 – 30 Fair 2 0 2 Douglas-fir 6 – 34 Fair – Good 20 0 20 Pacific Madrone 14 – 20 Fair 2 0 2 Red Alder 8 – 26 Dead – Fair 29 52 81 Scouler’s Willow 6 – 15 Very Poor – Fair 1 5 6 Western Hemlock 12 – 25 Dead – Fair 2 4 6 Western Redcedar 6 – 45 Dead – Good 37 14 51 Total 6 – 50 Dead - Good 175 93 268 The understory vegetation is dense with salmon berry (Rubus spectabilis), sword fern (Polystichum munitum), red huckleberry (Vaccinium parvifolium), bracken fern (Pteridium aquilinum), Himalayan black berry (Rubus armeniacus), and trailing blackberry (Rubus ursinus). There was also invasive Japanese knotweed (Reynoutria japonica) growing in the understory. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 4 Photo 1. View of typical trees and understory vegetation in Cover Type I. Type II. – This cover type encompasses all the trees around the existing homes. The trees in this type include both native and planted species. Species include Douglas-fir, cherry (Prunus spp.), western redcedar, shore pine (Pinus contorta), coastal redwood (Sequoia sempervirens), bigleaf maple, hawthorn (Crataegus spp.), Pacific dogwood (Cornus nuttallii), giant sequoia (Sequoiadendron giganteum), Colorado blue spruce (Picea pungens), Alaska cedar (Callitropsis nootkatensis), silver maple (Acer saccharinum), horse chestnut (Aesculus hippocastanum), European white birch (Betula pendulum), black locust (Robinia pseudoacacia), Leyland cypress (Cupressus × leylandii), Lombardy poplar (Populus nigra), English walnut (Juglans regia), Japanese maple (Acer palmatum), apple (Malus spp.), Chinese windmill palm (Trachycarpus fortune), arborvitae (Thuja spp.), and other hardwoods. Almost all of the trees in this type are in ‘Fair’ or better condition. The diameter range for the trees is from 6 to 48 inches DBH. The conifer in this type would make the best retention trees to save on-site. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 5 Table 2. Summary of Trees in Cover Type II. Species DBH Range (in.) Condition Range # of Healthy Significant Trees # of Unhealthy Significant Trees Total # of Trees Douglas-fir 6 – 40 Fair – Good 21 0 21 Cherry 8 – 15 Fair 7 0 7 Western Redcedar 6 – 44 Fair – Good 19 0 19 Shore Pine 15 – 22 Fair 4 0 4 Coastal Redwood 20 – 26 Good 2 0 2 Bigleaf Maple 6 - 48 Fair 27 0 27 Hawthorn 12 – 14 Fair 2 0 2 Pacific Dogwood 6 – 22 Dead – Fair 1 1 2 Giant Sequioa 20 Good 1 0 1 Colorado Blue Spruce 15 Good 1 0 1 Alaska Cedar 14 – 24 Good 3 0 3 Silver Maple 10 – 26 Fair 4 0 4 Horse Chestnut 16 Fair 2 0 2 European White Birch 15 Fair 1 0 1 Black Locust 6 – 24 Fair 14 0 14 Leyland Cypress 10 – 12 Good 8 0 8 Lombardy Poplar 24 – 30 Fair 4 0 4 English Walnut 10 – 15 Good 3 0 3 Japanese Maple 6 – 18 Good 2 0 2 Apple 6 – 16 Fair 13 0 13 Arborvitae 6 Good 14 0 14 Chinese Windmill Palm 10 Good 1 0 1 Other Hardwoods 6 - 10 Fair 5 0 5 Total 15 – 28 ‘Dead’ – ‘Fair’ 159 1 160 The understory vegetation is sparse with planted shrubs in the landscape, grass, and annual weeds. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 6 Photo 2. View of typical trees Cover Type II. Type III. – This forest cover type is the cleared, non-forest existing maintenance facility in the southern area of the site. There are a small number of trees within the landscape areas. All of the trees in this type are suitable for retention. Table 3. Summary of Trees in Cover Type III. Species DBH Range (in.) Condition Range # of Healthy Significant Trees # of Unhealthy Significant Trees Total # of Trees Douglas-fir 12 – 36 Fair – Good 11 0 11 Western Redcedar 6 – 38 Fair – Good 7 0 7 Giant Sequoia 6 – 54 Good 2 0 2 Mountain Ash 18 Fair 2 0 1 Norway Maple 12 Good 1 0 1 Vine Maple 6 Good 1 0 1 Other Hardwood 8 – 14 Fair 2 0 2 Total 6 – 54 Fair – Good 26 0 26 Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 7 The understory vegetation is very sparse and consists of shrubs in the landscape, grasses, and annual weeds. Photo 3. View of typical plants in Cover Type III. Overall Summary of Trees There are a total of 454 trees of which 360 are in ‘Fair’ or better condition. Trees in ‘Poor’, ‘Very Poor’, or that are ‘Dead’ are not considered to be long-term trees. These unhealthy trees have no potential to be saved in a development project. Off-Site Impacts Tree removal and grading for this project may impact off-site trees on the eastern side of the project area along the I-5 and Sound Transit rights-of-way. A tree risk assessment should be conducted on these trees after site clearing. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 8 Planned Tree Retention The current site plan shows the potential to retain 80 trees in the perimeter areas of the project. The required grading and other improvements limit tree retention on the remainder of the site. Once civil and grading plans are finalized a concluding count can be made to determine the total number of trees saved. Table 4. Planned Tree Retention: Existing Tree Diameters Tree Unit Credits # of Trees in Perimeter Area Total Tree Units Saved Existing Trees >6" to 12" DBH 1.5 23 34.5 Existing Trees >12" to 18" DBH 2.0 21 42 Existing Trees >18" to 24" DBH 2.5 14 35 Existing Trees >24 DBH 3.0 22 66 Totals 80 177.5 Tree Retention Calculations Federal Way municipal code 19.120.130 requires a minimum tree unit density of 25 tree units per acre for the current Single-family Residential zoning of the 14 parcels. If the zoning changes the density requirement will also change. The following is a summary of the planned tree retention and removal: Total Project Acreage: 13.87 acres Minimum Density Requirement (25 tree units/acre x 13.87 acres): 347.0 tree units Planned Tree Retention: 177.5 tree units Shortfall of Tree Unit Requirement: 169.5 tree units By retaining 177.5 tree units in 80 significant trees on the site, this plan falls short of the minimum tree density requirement by169.5 tree units. To meet the minimum tree density requirement replacement trees shall be planted. Replacement tree categories include small, medium, and large canopy species. Small canopy species count as 0.50 tree units, medium canopy species are 1.0 tree units, and large canopy species are 1.5 tree units. Different sized trees can be planted in combination to replace the tree unit deficit. Tree Protection Measures Trees to be saved must be protected during construction by a six-foot-high chain link fencing (Attachment 2), located 5 feet outside of the drip line of the trees. An existing fence surrounds much of the property – this should be adequate to protect these edges. Placards shall be placed on the fencing every 50 feet indicating the words, "NO TRESPASSING - Protected Trees". The Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 9 individual RPZ are a radius of one foot for each one inch of DBH (6 feet minimum), unless otherwise delineated by WFCI. There should be no equipment activity (including rototilling) within the critical root zone. No irrigation lines, trenches, or other utilities should be installed within the CRZ. Cuts or fills should impact no more than 25% of a tree’s root system. If topsoil is added to the root zone of a protected tree, the depth should not exceed 2 inches of a sandy loam or loamy fine sand topsoil and should not cover more than 25% of the root system. If roots are encountered outside the RPZ during construction, 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 impacting by grading or fills, then the tree should be re-evaluated by WFCI to determine if the tree can be saved with 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 parking lots or streets, and at least 10 feet of building clearance. 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®. Conclusions and Timeline for Activity 1. The final, approved tree conservation plan map should be included in the construction drawings for bid and construction of the project and should be labeled as such. 2. Stake and heavily flag the clearing limits. 3. Contact WFCI to attend pre-job conference and discuss tree protection issues with contractors. WFCI can verify all trees to be saved and/or removed are adequately marked for retention. WFCI can inspect and mark any additional hazard trees or trees that will be impacted by grading, trenching or development for removal in the save tree areas. 4. Complete logging. Complete necessary hazard tree removals and invasive plant removals from the tree protection areas. No equipment should enter the tree protection areas during logging. WFCI should inspect the save trees after logging, to identify any trees that may have been damaged, or any other hazard trees. The logger can then remove these trees before they depart the site. 5. Install tree protection fences along the 'limits of construction'. The fences should be located at the limits of construction or 5 feet outside of the drip line of the save tree or as otherwise specified by WFCI. 6. Complete clearing of the project. Maintain fences throughout construction. 7. Do not excavate stumps within 10’ of trees to be saved. These should be individually evaluated by WFCI to determine the method of removal. Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 10 8. Complete all necessary pruning on save trees or stand edges to provide at least 8’ of ground clearance near sidewalks and trails, and 15’ above all driveways or access roads. 9. Complete grading and construction of the project. Summary Federal Way municipal code 19.120.130 requires a minimum tree unit density of 25 tree units per acre for net developable acreage on Single-family Residential sites. The developable area is 13.87 acres, requiring 347.0 tree units to be retained on site. Eighty (80) healthy trees are planned to be retained on the site for a total of 177.5 tree units. This falls short of the required tree unit retention by 169.5 tree units. Small, medium, or large canopy trees shall be used to replace the tree unit shortfall. Please give us a call if you have any further questions. Respectfully submitted, Washington Forestry Consultants, Inc. Galen M. Wright, ACF, ASCA Joshua Sharpes ISA Bd. Certified Master Arborist PN-129BU Professional Forester Certified Forester No. 44 ISA Certified Arborist®, ISA Tree Risk Assessor Qualified Municipal Specialist, PN- 5939AM ASCA Tree and Plant Appraisal Qualified ISA Tree Risk Assessor Qualified Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 11 Attachment 1. Aerial Photo of Federal Way Operations and Maintenance Facility Site (King County iMap 2021) Project Boundary Forest Cover Type Boundaries I I NORTH NO SCALE III II Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 12 Attachment 2. Federal Way Operations and Maintenance Facility Site Plan Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 13 Project Boundary Planned Save Tree Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 14 Attachment 3. Tree Protection Fence Detail Temporary Chain Link on Driven Posts Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 15 Attachment 4. Individual Tree Rating Key for Tree Condition RATING SYMBOL DEFINITION Very Good VG • Balanced crown that is characteristic of the species • Normal lateral and terminal branch growth rates for the species and soil type • Stem sound, normal bark vigor • No root problems • No insect or disease problems • Long-term, attractive tree Good G • Crown lacking symmetry but nearly balanced • Normal lateral and terminal branch growth rates for the species and soil type • Minor twig dieback O.K. • Stem sound, normal bark vigor • No root problems • No or minor insect or disease problems – insignificant • Long-term tree Fair F • Crown lacking symmetry due to branch loss • Slow lateral and terminal branch growth rates for the species and soil type • Minor and major twig dieback – starting to decline • Stem partly unsound, slow diameter growth and low bark vigor • Minor root problems • Minor insect or disease problems • Short-term tree 10-30 years Poor P • Major branch loss – unsymmetrical crown • Greatly reduced growth • Several structurally import dead or branch scaffold branches • Stem has bark loss and significant decay with poor bark vigor • Root damage • Insect or disease problems – remedy required • Short-term tree 1-10 years Very Poor VP • Lacking adequate live crown for survival and growth • Severe decline • Minor and major twig dieback • Stem unsound, bark sloughing, previous stem or large branch failures, very poor bark vigor • Severe root problems or disease • No or minor insect or disease problems • Mortality expected within the next few years Dead DEAD • Dead Federal Way Operations and Maintenance Facility –Tree Conservation Plan Washington Forestry Consultants, Inc. Page 16 Attachment 5. 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.