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HomeMy WebLinkAboutAttachment_E_Tree_Assessment 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 February 15, 2023 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. There were two trees, a pine (Pinus contorta var. contorta), tree #1, and a red maple (Acer rubrum), tree #2, that were the focus of the site visit. The assessment was for current health, current risk and likely health impacts from the preliminary improvements proposed at the park. Two additional trees captured my attention during the site visit, they were both pine trees, #3 and 4. The preliminary park improvements include: 1. removing the existing restroom and pathways leading to it, 2. adding topsoil to the removed restroom area to create a raised knoll, tying together the surrounding mounds into one small hill to provide for positive drainage and prevent ponding, 3. removing the wood timber retaining wall to the east of the playground, 4. re-grading 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 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 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. The majority 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 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, indications of three or more branch failures and inadequate wound-wood formation at the branch failure sites. If this tree is not removed in the near future, next 1 to 3 years, it will likely die in this timeframe and need to be removed then. 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. 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. I suggest removing both trees #3 and 4 in conjunction with the park improvements if the park improvements include restroom removal and topsoil placement. 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 – remove. Tree #4 – remove. 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)