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HomeMy WebLinkAboutTR_Arborist_Report_250331_v2 Department of Natural Resources and Parks Parks and Recreation Division King Street Center, KSC-NR-5702 201 South Jackson Street, Suite 5702 Seattle, WA 98104-3855 http://www.kingcounty.gov/parks Page 1 of 5 March 31, 2025 Josh Tasler Parks Capital Project Manager King County Department of Natural Resources and Parks (206) 263-8993 RE: Boulevard Lane Park Select Tree Assessment Dear Mr. Tasler, I visited Boulevard Lane Park to assess two trees on February 8, 2023. The parcel is 733,114 sf (16.8 acres) and contains a developed park. The site contains mostly alder and cottonwood trees over 8 acres. A comprehensive survey of significant trees was not performed for the entire site, but a conservative estimate would likely find approximately 800 significant trees in these 8 acres. A significant tree is 6- inches diameter at breast height (DBH) and 8-inches DBH for alder and cottonwood. The developed park area is approximately 1.8 acres and contains approximately 30 significant trees, including pine, western red cedar, red maple, birch, and cottonwood. The proposed park improvements include: 1. remove the existing restroom and pathways leading to the restroom from the pathway that leads from the entrance to the playground, 2. place topsoil at the removed restroom area to create a raised knoll, tying together the surrounding mounds into one to provide for positive drainage and prevent ponding, 3. remove the wood timber retaining wall to the east of the playground, 4. re-grade the berm slope to the east of the playground to provide a gentler slope (3:1 or less) to the playground. Figure 1 Vicinity Map Page 2 of 5 THE SUBJECT TREES The tree assessment was for current health, current risk and likely health impacts from the preliminary improvements proposed at the park. Two trees were the primary focus of the site visit. Tree #1 is a pine (Pinus contorta var. contorta) and tree #2 is a red maple (Acer rubrum). Two additional trees captured my attention during the site visit, they were both pine trees, referred to hereafter as trees #3 and 4. Tree #1 Tree #1 is a 19.7-inch DBH pine tree to the southwest of the existing restroom. It is in good health, is not a high or extreme risk and would likely survive the proposed construction in good condition. Removal of the slightly overextended limb reaching to the southeast from the trunk, at approximately 12 feet above ground surface (AGS), would enhance the architecture of the tree and lower its risk. Image 1 - Tree #1 indicated with the arrow and the overextending limb off to the left in the image Page 3 of 5 Tree #2 Tree #2 is a 20.5-inch DBH red maple tree east of the playground and 4-feet from wood timber retaining wall. This tree is in good health, neither high nor extreme risk but would need to be removed to complete the proposed removal of the wood timber retaining wall and re-grading of the berm. Most of the canopy has a natural lean over the playground. The removal of this tree will not be detrimental to the privacy of the neighbors (12503 SE 188th Place) because there is a clump of bamboo beyond tree #2 providing a visual barrier for the house and yard. Image 2 - Tree #2 indicated with the arrow Page 4 of 5 Tree #3 Tree #3, a 10.6-inch DBH pine is 7 feet west of the garbage can at the northwest corner of the restroom and shows multiple signs of decline – less than 5% live canopy ratio (i.e. only 5% of its canopy has live, green needles), indications of three or more branch failures, and inadequate wound-wood formation at the branch failure sites (an indication of poor vigor). If this tree is not removed soon, it will likely die in next 1 to 3 years. Tree #4 Tree #4 is a 22-inch DBH pine that is 7 feet north of the garbage can at the northwest corner of the restroom. This tree has approximately 4 feet of included bark, from 6-feet AGS to 10-feet AGS, at the codominant stem union. Included bark can weaken the attachment point between two stems. There is indication of a branch failure wound on the west stem at 7-feet AGS (notably within the included bark zone of the western stem). This branch failure wound is seeping a sooty brown substance. Most salient, this tree has an isolated root zone that is within the bathroom removal area; it’s root zone will be detrimentally impacted (smothered) if the tree is retained and fill is placed. A red maple to the west of both trees #3 and 4 will eagerly expand into the canopy space that is cleared with the removal of these two trees. Image 3 - Trees #3 (on left) and #4 (on right) Page 5 of 5 Recommendations Based on the preliminary park improvements being proposed and the current health, condition, and risk of the trees surrounding the playground I suggest the following: Tree #1 – retain but prune the limb reaching to the southeast, at approximately 12 feet AGS. Tree #2 – remove. Tree #3 – retain. Tree #4 – remove. Potential replacement trees include vine maple (Acer circinatum), grand fir (Abies grandis), Oregon ash (Fraxinus latifolia), and shore pine (Pinus contorta var. contorta). Sincerely, Tom Early Parks Capital Project Manager King County Department of Natural Resources and Parks (206) 477-7555 / tearly@kingcounty.gov Landscape Architect (WA-1199) ISA Certified Arborist with a Tree Risk Assessment Qualification (PN-5622A)