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HomeMy WebLinkAboutRS_Arborist_Report_190315_v1.pdf13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 December 11, 2018 Project: Pre-construction assessment for property re-development at 1132 Edmonds Ave NE, Renton, WA. Parcel number 092305-9080. Contact: Brent Chastain - Third Place Design 341 NE 91st Street Seattle, WA 98115 Phone – 206 920 9996 Email – Brent@thirdplacedesigncoop.com Objectives: Evaluate health of existing trees and establish criteria for the preservation of those to be retained. Description: The Renton Housing Authority purchased the subject property in 2003. They had the City of Renton Fire Department demolish the existing house in 2004. As of 2002 the property was about half covered with trees. In 2005 the tree cover had been reduced to about thirty percent and the area bulldozed where the house had been (Figure 1). Currently the canopy cover is approaching forty percent (Figure 2). In 2012 the Housing Authority developed the adjoining lots to the east. They are now proposing extending the existing campus onto the subject property as shown in Figure 3. The new area will cover the east half of the 1132 property. The following itemized list begins in the northeast corner of the property. It includes the trees currently on the property and those within 10’ of the borders. The alphanumeric designations are reflected in the tree plots shown in Figure 4. The lettered trees stand outside the borders and the numbered trees within. The diameters measured were taken at the standard height of 54” above grade (DSH). The majority of the trees within the parcel were tagged. A) (Not tagged) Big Leaf Maple (Acer macrophyllum) with four main stems 13”, 14”, 15” and 15” DSH, 65’ tall, with a 20’ radial spread standing 7’ E of the east fence line and 16’ south of the NE corner of the subject property. Tree is in fair condition with average new growth and decent color. B) (Not tagged) Line of seven cedar (Thuja plicata) 6-8” DSH, 14-18’ tall standing 5’ east of the fence line between the maple above and the NE corner of the property. They are in fair condition and are forming a hedge row. 1) Pacific Dogwood 10.5” DSH, 30’ tall, 8’ spread mainly to the west. The tree stands 46’ S of the NE corner and 25’ W of the existing east fence line. Tree is in fair condition with normal growth and color for its age category. Enterprises 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 2) Three stem cottonwood (Populus trichocarpa) 10.5”, 12”, and 13” DSH, 65’ tall, 12’ spread off of a 40” diameter base. It stands 26’ W of the #1 tree and roughly 8’ N of it. The tree appears to be formed from stump sprouts. Two of the stems lean markedly, the 10’5” one to the north and the 12” one to the east. There is an open decay column in the center of the main stump. The tree has robust new growth and good color. 3) Cedar 30” DSH, 50’ tall, standing 10’ north of #2 tree. It is in good condition with abundant new growth, vibrant color, excellent height to diameter ratio, and a full canopy which descends to ground level. 4) Cottonwood 7.5” DSH, 55’ tall, 6’ spread standing 15’ S of the north fence line and 18’ W of the #3 cedar. Tree is in weak structural condition and fair health. 5) Cottonwood 7” and 9.5” DSH, 50’ tall, 7’ spread standing 30’ W of and in line with the #4 tree. It is in fair health and weak structural condition. 6) Cottonwood 11” DSH, 50’ tall, 9’ spread standing 17’ S of #5 tree. It is in fair condition. 7) (Not tagged) Cottonwood 7” DSH, 45’ tall, 6’ spread standing 9’ W and 3’ N of #5 tree. It is in fair condition. 8) (Not tagged) Cottonwood 6” DSH, 40’ tall, 5’ spread standing 7’ W of #7 tree. It is in fair condition. 9) Cottonwood 8.5” DSH, 50’ tall, 6’ spread standing 16’ S of the #8 tree and 11.5’ WNW of #6. It is in fair condition. 10) Cottonwood 6.5” DSH, 35’ tall, 5’ spread standing 27’ S and 3’ W of the #6 tree. It is in fair condition. 11) Cottonwood 8” DSH, 45’ tall, 6’ spread standing 8’ S of #10 tree. It is in fair condition. 12) Cottonwood 10.5” DSH, 50’ tall, 8’ spread standing 4’ SW of #11 tree. It is in fair condition. 13) Cottonwood 7.5” DSH, 40’ tall, 5’ spread standing 52’ S of #2 and 52’ W of the surveyed east side line. It is in fair condition. 14) Alder (Alnus rubra) 17.5” DSH, 35’ tall, 10’ spread standing 41’ S of #13. Tree has advanced decay present along the column and the upper half of the canopy is dead. 15) Pacific Madrone (Arbutus menziesii) 17” DSH, 45’ tall, 9’ spread in fair condition. The tree has average color, fairly balanced canopy, and average new growth. It stands 16’ SE of the #14 alder. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 16) Wild Cherry (Prunus emarginata) 14” DSH, 35’ tall, no branches. The tree is dead. It stands 22’ NE of #15. 17) (Not tagged) Hazel grove (Corylus sp) formed of multiple intertwining clumps. It starts 12’ north of the #16 cherry and runs 90’ to the south. It is as much as 25’ wide. Fair condition overall with normal amounts of deadwood. Some of the stems exceed 6” in diameter and reach 18’ tall. 18) Black Locust (Robinia pseudoacacia) 9.5” DSH, 35’ tall, 9’ spread mainly to the west. The tree is standing 4’ W and 3’ N of the SW corner marker stake for the 1141 lot. Tree is in fair condition with average new growth, decent color, and reasonable structural formation. 19) (Not tagged) Black Locust 10” DSH, 45’ tall, 10’ spread standing 10’ S of the #18 tree. In fair condition. Following trees are taken from the survey plot. Author thought the corner marker for the 1141 lot was the SE one for the subject property. The trees were visually noted at the time of the survey but not tagged or recorded. 19a) Black locust 12”, 45’ tall, 9’ spread. Fair condition. Standing 6’ S of #19. 19b) Black locust 13”, 45’ tall, 9’ spread. Fair condition. Standing 5’ S of #19a. 19c) Black locust 13”, 45’ tall, 9’ spread. Fair condition. Standing 4’ W of #19b. 19d) Black locust 13”, 45’ tall, 9’ spread. Fair condition. Standing 10’ W of #19c. 20) Three stem Wild Cherry 8.5”, 10”, and 10” DSH, 35’ tall, 6’ spread standing 46’ west of the east fence line 30’ north of the south fence (second measurement taken from survey). It is in poor condition and appears to be dying. 21) Wild Cherry 9.5” DSH, 35’ tall, 5’ spread standing 8’ WNW of the #20 tree. It is in weak condition with poor color and limited canopy coverage. It has a 5” caliper holly twining around it. 22) Wild Cherry, dual stem from the base, 12.5” and 14” DSH, 45’ tall, 9’ spread. The east (14”) stem is dead and the west one is dying. It stands 22’ W of #21. Three cherry saplings stand west of it and all are less than 5” DSH. 23) A wild cherry 10.5” DSH, 45’ tall, 8’ spread standing 16’ S of #22 and roughly 22’ N of the south fence. 24) English laurel grove, essentially a hedge which has gone feral, growing along the south fence line. It starts near the #23 tree and runs west for 90’. It is in fair condition. C) (Not tagged) Big Leaf Maple standing 3’ to the south side of the south fence, 12” DSH, 40’ tall, 16’ spread mainly to the south. Fair condition. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 25) Wild Cherry 6.5” DSH, 45’ tall, 5’ spread in weak condition, 13’ W of the #23 tree. 26) Wild Cherry 7” DSH, 45’ tall, 5’ spread in weak condition, 9’ S of the #25 tree. 27) (Not tagged) Holly grove (Ilex aquifolium) growing between the #26 and the #28 trees. It is in fair condition over all showing color and growth typical of the species. The largest stems approach 4” DSH but the majority are in the 1-2” range. 28) Wild Cherry 6.5” DSH, 40’ tall, 5’ spread in weak condition, 13’ W of the #26 tree and 15’ N of the south fence line. 29) Wild Cherry 7” DSH, 40’ tall, 6’ spread in weak condition, 5’ S of the #28 tree. 30) Wild Cherry 8” DSH, 45’ tall, 6’ spread in weak condition, 6’ N of the #28 tree. 31) Wild Cherry 8.5” DSH, 50’ tall, 6’ spread in weak condition, 5’ NE of #30 tree. There is a 3.5” hawthorn sapling and two 4” caliper cherries near this tree. 32) Wild Cherry 9” and 6.5” DSH, 40’’ tall, 8’ spread in poor condition standing 26’ N of the #31 tree. 33) Dead alder 16.5” DSH, 35’ tall standing 14’ N of #32 tree. 34) Apple (Malus sp) standing 22’ W of #34 tree. Tree rises off of a 14” caliper base, separates at the 28” level into two 10” caliper stems. They both grow to the south at 45 degrees, one turns up toward vertical 10’ out from the bifurcation point. Tree is in weak condition. 35) A Cascara (Rhamnus pushiana) standing 17’ S of the #34 apple. The tree had two 10” DSH main stems which bifurcated at the base but one broke out at the 5’ mark, the other rises to the 30’ level. The remaining stem is hollow with advanced decay present. There are five daughter stems in the 3.5” caliper range growing off the tree’s base. The #34 apple is leaning over this tree. 36) Wild cherry10.5” DSH, 60’ tall, 8’ spread in fair condition standing 31’ SSE of #35 and in the middle of the last stand of laurel from the #24 hedge row. 37) Wild Cherry 6.5” and 7.5” DSH, 40’ tall, 5’ spread in weak condition standing 18’ W of the #35 tree. There are three dead cherry stems 8’ to its south, all less than 5” DSH. 38) Wild Cherry standing 8’ W and 1’ S of the #37 tree. Tree has a 7” DSH, is 30’ tall, and has a 5’ spread. It is mostly dead. There is a 4” cherry sapling next to it. 39) Wild Cherry 6.5” DSH, 30’ tall, 5’ spread standing 6’ WNW of #38. Poor condition. 40) Wild Cherry 6.5” DSH, 30’ tall, 5’ spread and 3” DSH, 25’ tall, 3’ spread standing 3’ NW of #39. Tree is in poor condition. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 41) (Not tagged) Hazel grove starting 21’ W of the end of the #24 English laurel. There are three clumps 15’ wide running north from the south fence and ending about even with the #40 tree. Fair condition overall. 42) Hawthorn (Crataegus sp) 6.5” DSH, 30’ tall, 6’ spread standing center north of #41 grove, 22’ W and 5’ S of #39. Tree is in fair condition. 43) (Not tagged) Holly grove standing on the west side of the #41 hazel. Runs 16’ to the west and14’ deep to the north. Some of the stems are greater than 6” DSH. Fair condition. 44) Wild Cherry grove with six stems 6.5-8.5” DSH, 50’ tall, 6’ spreads in fair condition. The first stem stands 18’ W of #42 and 11’ N of the south fence line at the edge of the #43 holly. The grove extends 12’ to the west. 45) Wild cherry 6.5” DSH, 45’ tall, 5’ spread in fair condition. It stands 2’ N of the south fence line and in line with the last tree in the #44 stand. 46) Juniper tree (Juniperus sp) with a 12.5” DSH, 35’ tall in fair condition. It stands 17’ north of the south fence and roughly 8’ northwest of the last tree in the #44 row 47) Wild cherry 7” DSH, 45’ tall, 9’ spread all to the north. It is in fair condition and stands 7’ N of #46. 48) Wild Cherry 7.5” DSH, 55’ tall, 6’ spread standing 10’ SW of #46, 15’ WNW of #45, and 8’ N of the south fence line. It was recently girdled at the 4’ level and is dying. 49) Wild Cherry 6” DSH, 50’ tall, 6’ spread mainly to the west. It stands 5’ W of #48 and 8’ N of the fence line. It is in fair condition. 50) Wild Cherry 6.5” DSH, 45’ tall, 6’ spread standing 10’ N of #48, 8’ w of #46. Tree bifurcates at the 20’ level. It is in fair condition. 51) Wild Cherry 8.5” DSH, 55’ tall, 7’ spread standing on the south fence line 28’ west of the #45 tree. It is in fair condition. 52) Mixed grove of hazel and holly spread out to the west of the #51 tree. It extends to the SW corner of the property and up to 30’ north of the fence line. It is in fair overall condition. There are some stems greater than 6” DSH but most are less. 53) Engelmann spruce (Picea engelmannii) 17.5” DSH, 35’ tall standing 38’ N of the south fence line and about even with the #42 tree. It is in good condition with a full canopy down to the 7’ level. 54) Wild Cherry 6” DSH, 40’ tall standing 17’ west of the #53 tree. It is in weak condition. A 5.5” sister stem stand 3’ south of it. 55) Norway spruce (Picea abies) 12.5” DSH, 35’ tall standing 6’ west of the #54 tree. It is in fair condition and its canopy comes down to the 6’ level. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 56) White spruce (Picea glauca) 11.5” DSH, 35’ tall standing 10’ N of the #55 tree. It is in weak condition. The upper quarter of the canopy is fine but the lower half on the west side is sparse and the lower 2/3 on the east side has numerous dead or dying branches. 57) Pacific Madrone 37.5” DSH, 55’ tall, 23’ spread to the east, 38’ spread on a lateral arm to the SW, and 25’ to the NW. Tree stands 46’ W of the #34 apple and 50’ N of the south fence line. It is an exceptional tree in excellent health with abundant new growth, vibrant color, and limited instances of canker and blight. 58) Douglas Fir (Pseudotsuga menziesii) 38.5” DSH, 90’ tall in good health overall. It is standing 20’ ENE of the #57 tree. It has a full canopy which descends to near the 12’ level. The fir bifurcates at the 60” level in a N/S plane, the west side is 26” caliper, and the east side is 28” caliper. 59) Alder 24.5” DSH, 35’ tall, 18’ spread standing 20’ ENE of the #58 fir. The upper half of the canopy is dead, it has advanced decay along the column, and the live canopy is mostly formed of vertical epicormics extending off of up reaching laterals. 60) Black Locust 10.5” DSH, 18’ tall, 9’ spread standing near the center west side of the parcel, about 25’ SE of the top of the existing driveway. It is in fair condition. 61) Cottonwood grove which starts 25’ west of the #10-12 tree row, 45’ south of the north fence line, and pushes up against the upper driveway. It is 50’ wide east to west and about 40’ north to south. It is in fair health overall. There are eighteen primary stems in the grove many of which lean out markedly giving them weak structural conditions. The tallest of the trees reach 60’ and their DSHs ranged from 6” to 10”. 62) Wild Cherry grove which stands between the #61 grove and the north fence line. Its east edge begins roughly 35’ west of the #9 tree and it averaged 38’ wide east to west. The sixteen main trunks ranged from 4” DSH to 10” DSH and they maxed out around 40’ tall. The trees were in below average health for the most part. 63) Norway Spruce 22.5” DSH, 55’ tall in good condition standing 25’ south of the rock retaining wall on the south side of the existing driveway. It is 18’ east of the retaining wall running along the sidewalk on the west side of the property. It has a low, full canopy. Ivy is climbing up through the tree. 63a) (Not tagged) Dead alder stands in the curve of the rock wall at the south corner of the driveway entrance. It is large enough to reach Edmonds Avenue. 64) Douglas Fir 35” DSH, 100’ tall standing 24’ S of #63 and 9’ E of the west side rock wall. It is in fair condition. There is ivy present in the tree. 65) (Not tagged) Big Leaf Maple clump formed of 9 stems ranging from 5” to 19” DSH, 55’ tall, with a 28’ spread to the west and a 22’ spread to the east, north, and south. It is roughly 35’ S of #64 and stands at the edge of the rock wall. It is in fair condition. The lower scaffolds on the west side are overweight, over extended, and hang over the sidewalk and Edmonds Avenue. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 66) (Not tagged) Holly grove growing up under and against the east side of the #65 clump. It is up to 20’ tall, runs about 20’ north to south and 10’ wide east to west. The largest stem(s) are no more than 6” DSH. Average condition. 67) (Not tagged) Big Leaf Maple 19” DSH, 50’ tall, 20’ spread to the west side, slightly less to the east. It stands close to the SW corner of the property roughly 70’ south of #65. It is in fair health, leans slightly to the west, and the majority of the canopy is on the west side. 68) (Not tagged) Big Leaf Maple 32” DSH, 65’ tall, 28’ spread standing at the top of the rock wall on the north side of the driveway entrance. The base of the tree is just 6’ back from the wall. There is ivy climbing up into the mid canopy. It is in fair health. 69) Big Leaf Maple standing at the NW corner of the property 28” back from the rock wall. It has a 16” DSH, is 50’ tall, and has a 15’ fairly even radial spread. It has ivy growing up through it but appears to be in fair health. Methods: Tree assessment is both an art and a science. To properly perform, an arborist must have an extensive background in biology, tree mechanics, and tree structure that is equal parts academic and field knowledge. It takes years of study to recognize and correctly diagnose the subtle signs trees exhibit before their failure, whether it be partial or total. The process begins with a visual inspection (visual tree assessment, VTA) which is followed up as necessary with soundings, core testing, and/or other detection means. Each tree is examined and evaluated according to several factors including species type, size, vigor, injuries present, root and grade disturbance, deadwood, location and extent of decay, stem taper, exposure, and targets that are at risk. Risk Assessment: None of the trees present on the subject property would classify out as a high risk. Having said that there are two immediate issues which should be remedied. The #63a dead alder should be removed in the short term as it will fail and fall into the street. The lower branches on the #65 maple clump should be pruned for weight/length reduction to prevent failure which may result in a car or person being struck. Cottonwood trees are notorious for being weak in structure. They are one of a handful of species that are known to be susceptible to the sudden limb drop phenomenon, a condition where a tree will shed a large limb on a calm day for no apparent reason. They also appear consistently in the tree failure data base with failed crotches, broken limbs, sheared spars, and uprooting. The more rapid the growth of these trees the more prone they become to these types of failure. The black cottonwood can reach its mature height of up to 200’ in sixty to seventy years. The cottonwoods growing on the property are quite young, most likely less than fifteen years old for the most part. They are growing extremely rapidly and will be quite prone to partial and catastrophic failure. It is highly recommended that all the cottonwoods on the property be removed at this time. It will be a simple affair at this point and the mulch can be blown out over the property. This will prevent much future heartache and safety issues and save a considerable amount of money for the Housing Authority. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Discussion: There are two levels of impact at this site, primary and secondary. The primary area includes the environs immediately within the boundaries of the proposed new construction, including the driveway, and the regions within ten feet of those boundaries. The secondary area includes regions where work occurs more than 10’ from the base of the trees in question but within their root zones. In this case all the trees within a rectangular area on the east side of the parcel measured 140’ west from the NE corner and 200’ south from north fence will be removed. There is only one tree in this region that could be construed as being worth retention, namely the #3 cedar. However, as this tree is right in the middle of the area where the northern town home will be built, and as its retention would preclude building any structure with 20’ of its base, meaning only two building could be built or the whole site would have to be re-thought, it is not worth retaining. Below this area is a smaller rectangle 105’ west from the SE corner and 65’ north of the south fence. There are no trees at all worth keeping in this zone. Taken together all the trees from #1 through #33 (obviously only the east end of #24 hedge) and the #59 tree will be removed during the clearing and grading process. The ‘C’ maple is within 10’ of the potential grading/excavation impact but, as it is on the neighboring property, will be retained. It will be discussed in the sections below. The excavation for the new foundations and other hardscaping will potentially cross into the Critical Root Zone (CRZ) of three of the trees, namely the ‘C’ maple, the #58 Douglas Fir, and the east side tree(s) of the #62 cherry grove. This region is defined as a radial distance equal to one foot per inch of tree diameter. A Certified Arborist will have to be onsite to evaluate the degree of impact and help design a mitigation scenario according to onsite realities. As the work begins to expose roots, systematic hand root pruning, rather than tearing and shearing by machine, should be done. For example the ‘C’ maple, with an12 inch DSH, has a 12 foot radial CRZ. The tree stands 3’ over the line and the excavation to its north side will be around 5’ north of the line, so there will be impact about 8’ out from its base. Trenching type incursion, that is excavation that will occur along only one sector of a tree’s CRZ, can reach significantly into the root growth area without having a detrimental long term effect. What does have to be absolutely protected is a tree’s Structural Root Plate (SRP). This radial area is again related to the diameter inches of the tree in question but not quite in a direct proportion as in the CRZ. Figure 5 below illustrates the relationship. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Figure 5. Size of the Structural Root Plate in relation to tree stem diameter. Note that the SRP levels off at 10’ for any tree over 24” in diameter. In the case of the ‘C’ maple mentioned above, the excavation for the new north side foundation could come as near as 8’ to the base of the tree. From Figure 5 the Structural Root Plate for an 12” DSH tree is given as 6.5’ so the grading work should not interfere with its SRP. The #58 fir has a 10’ SRP and according to the plan set the grading for the parking area will be more than 20’ away. Assuming that the largest of the #62 cherries stands the closest to the impact zone, a 10” tree has a 6’ SRP and the northern grading work appears to remain at least 10’ outside of it. The chart shown in Figure 6 below is used to determine what percentage of a tree’s Critical Root Zone will be affected by trenching type incursion. In general trees can sustain losses of up to 30% of the overall area within their CRZ without having long term detrimental results. Figure 6. Chart giving the loss in critical root area as a function of the radial distance to the CRZ disturbance. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Using the ‘C’ maple again as the example, with the excavation being 8’ from the tree’s base and it having an 12” DSH, there will be impact at a linear distance equal to 67% of the maples CRZ. The chart shows that this equates to around a 28% loss in Critical Root Area (CRA) and the young maple should be fine long term. The CRA loss on the east side of the #58 fir (22’/38.5” DSH) would be roughly 32%, just over the recommended allowance. However, the cut for the south end overflow parking stops about even with the center of the tree. So in reality it will experience about half that impact, closer to 16%, and should be expected to survive the impact with no long term detrimental effects. The #62 cherry has a 10’ radial Critical Root Zone and the grading may just brush the edge of it. Using 90% of CRZ the distance the tree would be expected to lose less than 10% of its CRA and be just fine. Note that while the trees within the #61 cottonwood grove stand outside the impact zone they are tall enough to land within the developed area. These cottonwoods will reach more than 100’ tall in another four to six years. This places both upper townhomes will inside their strike zones. Their removal at this time will alleviate this issue. Typically fencing is installed to designate no impact zones and is placed at the distance proscribed by the arboricultural industry for non-incursion which is one linear foot per linear inch of diameter. Orange vinyl barrier fencing can be used, although chain link is preferred. In this case it will be much simpler to fence off the west side of the property. The fence can run straight down at the 140’ construction limit, tuck in to the 105’ lower area distance, and continue down to tie into the south fence. This fence will have to jog around the CRZ for the #58 fir and should only be moved under arborist oversite. A small section of fencing will have to be place around the CRZ of the ‘C’ maple and it also should only be moved under supervision. Recommendations: While preserving green spaces and the resulting biological diversity is important, trees that pose threats to persons or property must be managed so that safety is the highest priority. In this case the #63a alder should be removed during the initial clearing and grading period and it is strongly recommended that the #61 cottonwood grove be cut down at this time also. As noted above, all the east side trees (1-33, 59) should be removed during construction onset. It would be advisable to have the #65 maple pruned during the beginning of the project in order to mitigate its risk issues. The #57 madrone is an iconic tree and special care should be taken to protect it over the course of this, or any future, project. Absolutely NO IMPACT OF ANY KIND SHOULD OCCUR WITH THIS TREE’S 38.5 FOOT RADIAL CRITICAL ROOT ZONE. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Waiver of Liability Because the science of tree risk assessment is constantly broadening its understanding, it cannot be said to be an exact science. Every tree is different and performing tree risk assessment is a continual learning process. Many variables beyond the control, or immediate knowledge, of the arborist involved may adversely affect a tree and cause its premature failure. Internal cracks and faults, undetectable root rot, unexposed construction damage, interior decay, and even nutrient deficiencies can be debilitating factors. Changes in circumstance and condition can also lead to a tree’s rapid deterioration and resulting instability. All trees have a risk of failure. As they increase in stature and mass their risk of breakdown also increases, eventual failure is inevitable. While every effort has been taken to provide the most thorough and accurate snapshot of the trees’ health, it is just that, a snapshot, a frozen moment in time. These findings do not guarantee future safety nor are they predictions of imminent events. It is the responsibility of the property owner to adequately care for the tree(s) in question by utilizing the proper professionals and to schedule future assessments in a timely fashion. This report and all attachments, enclosures, and references, are confidential and are for the use of Brent Chastain, Third Place Design, the Renton Housing Authority, and their representatives only. They may not be reproduced, used in any way, or disseminated in any form without the prior consent of the client concerned. Anthony Moran, BS Certified Arborist Qualified Tree Risk Assessor ISA #PN-5847A 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Figure 1. Aerial view of the lot circa 2005. Note the concentration of trees along the perimeter of the property. Figure 2. Aerial view from 2017 showing a much greater lot canopy coverage. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Figure 3. Concept of site redevelopment. Compare to existing canopy above. The area shown only covers 130’ to the west out of the 290’ wide parcel. 13110 NE 177th Place #304 * Woodinville, WA 98072 * Anthony@SuperiorNW.com 206-930-5724 Figure 4. Current aerial view of subject property. The white numerals correspond to the nomenclature in the description section and show rough placement of the indicated trees. Please refer to the most recent survey for exact locations.