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HomeMy WebLinkAboutTR_A.B.C._Consulting_Arborists_LLC._Risk_Assessment_180628 A.B.C Consulting Arborists LLC Accurate Balanced Certified Dan Tree Risk & Viability Assessment May 11, 2018 PREPARED FOR: Jerry Koch C/O Dan Koch 419 S. 19th ST. Renton WA. PREPARED BY: A.B.C. Consulting Arborists LLC Daniel Maple, Consultant Registered Consulting Arborist #627 ISA Municipal Specialist # PN-7970AM ISA Tree Risk Assessment Qualified (TRAQ) ISA Board Certified Master Arborist #PN-7970BM Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 2 of 19 TABLE OF CONTENTS INTRODUCTION..................................................................................................................................... 3 ASSIGNMENT .......................................................................................................................................... 3 PURPOSE .................................................................................................................................................. 3 METHODOLOGY ................................................................................................................................... 3 TREE LOCATION AND ID .................................................................................................................... 4 OBSERVATIONS ..................................................................................................................................... 4 The Site ................................................................................................................................................... 4 The Trees ................................................................................................................................................ 4 Additional Testing .................................................................................................................................. 4 Limitations .............................................................................................................................................. 4 DISCUSSION ............................................................................................................................................ 5 Species Profile ........................................................................................................................................ 5 CONCLUSIONS AND RECOMMENDATIONS .................................................................................. 5 Recommendation .................................................................................................................................... 6 WAIVER OF LIABILITY ....................................................................................................................... 7 ATTACHMENTS ..................................................................................................................................... 7 Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 3 of 19 INTRODUCTION In April 2018, Mr. Dan Koch contacted me, on behalf of his father Mr. Jerry Koch, to get information on the process of having his father’s trees assessed for risk and structural stability. Mr. Koch recently removed a popular tree behind his home that had partially failed. An examination of the tree stump showed the interior was mostly hollow. Mr. Koch was concerned about the safety of the remaining popular trees and wanted them assessed. As a result of our conversation Mr. Dan Kock contracted me, on behalf of his father, to perform a level 2 Risk Assessment and Level 3 Assessment (drilling for internal decay) as I deemed prudent, on all the popular trees in the backyard of the above address. I am to present my observations, analysis, and recommendations in a written report. A site visit was scheduled for May 7, 2018. ASSIGNMENT I agreed to provide the following: • A level 2 Risk Assessment and drilling for internal decay of all the popular trees in back of 419 S. 19th ST. Renton WA. • Recommendations to mitigate any noted risks. • Provide a written report of my observations, analysis and recommendations. PURPOSE This report is intended to identify and reduce exposure to tree related risks: • To identify tree(s) defects that pose a risk(s) to the above and neighboring home(s) and personal property, as well as the owners and their guests. • Provide reasonable mitigation options to reduce risk to acceptable levels. • To document tree hazards for obtaining a tree cutting permit if one is required. (additional ISA risk assessment forms are available if needed) METHODOLOGY To evaluate the tree(s) for risk and prepare this report I drew upon my 30+ years of experience in the field of arboriculture and my formal education. Following the protocol established by the International Society of Arboriculture (ISA) Best Management Practices (BMP) for Risk Assessment ANSI A300 part 9. The site was assessed for any noted condition that may have a negative impact on the local forest including but not limited to: 1) history of tree failure (wind throw) 2) Change in Wind Patterns 3) soil depth 4) Soil Hydrology 5) grade changes 6) fungal fruiting bodies/decay pathogens. On date Referenced above, I performed a level 2 risk assessment on the subject trees and: 1. The crown of the tree(s) were examined for current vigor. Inspecting the crown (foliage, buds and branches) for color, density, form, and annual shoot growth, limb dieback and disease. Branches were inspected for cracks and other defects, as well as needs for remedial pruning. 2. The bole or main stem of the tree(s) was inspected for decay, which includes cavities, wounds, fruiting bodies of decay (conks or mushrooms), seams, insects, bleeding, callus development, broken or dead tops, structural defects and unnatural leans. Structural defects include crooks, forks with V-shaped crotches, multiple attachments, and excessive sweep. 3. The root collar and roots were inspected for the presence of decay, insects and/or damage, as well as if they had been injured, undermined or exposed, or original grade has been changed. Inspection tools included: binoculars, hypsometer, diameter tape, mallet, trowel, & probe. Level 3 Advanced Assessment: Root/Trunk decay testing with Resistograph® was included. Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 4 of 19 TREE LOCATION AND ID The trees were tagged with aluminum tags and numbered 1-11. Please refer to Attachment 1, Tree Plotter Image for an orientation to the site and the approximate location of the trees. OBSERVATIONS The Site An 15,000 sq. ft. (0.34-acre) residential lot zoned R-8. The single-family dwelling was built in 1949. Soils are native, moderate in depth, mildly compacted, with moderate to high moisture content. 1 tree partially failed in the past and was removed. Trees are exposed to the prevailing S/SW winds. No other relevant site conditions were noted. The Trees The trees are 50+ year old, over mature specimens ranging from 18” to 60” DBH, with most being from 30” to 60” and an average height of 90-100 feet tall. The trees appeared to be in general good health and vigor (except #8 was in poor health), with good buttress root formation (especially on the N. side or windward), extensive cankers were noted throughout the trees. Several of the trees had co-dominate trunks with included bark unions (high failure point). A tree between #6 and #7 had partially failed and was removed. A closer inspection of the decayed area revealed soft spongy wood indicating the Lombardy poplar was afflicted with white rot, no decay fungi was noted. White rot fungi cause the lignin (wood) and hemicellulose within the wood to break down first leaving behind the cellulose fibers which provide the tree with tensile strength and flexibility (Weber and Mattheck, 2003). In this case, the degradation of lignin has resulted in a loss of strength within this aspect of the tree causing the failure. Due to the level of decay noted, the remaining 11 trees were tested for internal decay. See Attachment 2 Photos and Attachment 3 Tree Summary/Risk Assessment Form for details. Additional Testing Lombardy poplars are fast growing, short lived trees and it is not uncommon for decay to be present within the base of a trunk. Given there were no significant outwardly visible signs of decay in the previously failed tree, and in order to ascertain the presence of internal decay in the remaining trees, I deemed it necessary to undertake an internal decay detecting assessment (i.e. through resistograph tests). Minor to advanced decay was noted in most of the trees. See Attachment 4 for complete results. Limitations There are limits when testing for internal decay, the test site could go to the side of the decay, or the level of root decay could be enough to cause whole tree failure but not have advanced far enough into the roots/root crown to be detected. We took every reasonable effort to accurately determine the level of risk associated with the trees, however, it is possible that internal decay may exist and not been detected. This report is not a health assessment, nutrient analysis, or quote to provide services, it is limited to the scope of the assignment. Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 5 of 19 DISCUSSION Species Profile The Lombardy poplar is a variety of the black poplar (Populus nigra “Italica”); so-called because it originates from the Lombardy region of Northern Italy (Tebbs, 1984). The Lombardy poplar spread worldwide in the eighteenth century (Wood, 1994) and was introduced into New Zealand during the 1830’s as a shelter and amenity tree on farms and public places (National Poplar and Willow Users Group, 2007). The Lombardy poplar is a short-lived (20-30 years, rarely over 50-years), rapidly growing tree with a distinctively columnar shape, often with a buttress base (Wood, 1994) and attains a height of 100 feet. (Tebbs, 1984). The tree is prone to cankers (especially in hot, humid climates) that are often fatal. The Lombardy poplar is a shallow rooted tree that stabilizes itself by forming a large root plate and stiff buttresses roots. The species generally forms buttress roots on the windward side of the tree, especially when growing on high water table sites. The tree is resistant to root delamination and, if it does fail, it is usually because of extensive butt-rot. The Lombardy poplar’s restricted rooting depth anchors itself in a way that tropical trees balance themselves on wet land by means of their giant buttress roots (Mattheck and Breloer, 1994). Despite the Lombardy poplar tree’s buttress root form, like other members of the genus, the wood is weak and is prone to breaking (Wood, 1994). The Lombardy popular is a poor compartmentalizer of decay, and its defense mechanism is to outgrow rather than contain the spread of decay. The rapid growth put on by the tree to replace the lost wood and structural integrity caused by decay is called response wood. Response wood has different chemical and strength properties than normal wood and may replace the losses caused by decay (Matheny, Clark, 1997). Moderate to high levels of decay with little to no response wood, suggests the tree is in poor vigor, or decay is spreading faster than the tree can respond to the losses (Matheny, Clark, 1997). Over time the spread of the decay will outpace the trees ability to replace the loss of structural strength, and tree failure will occur (Matheny, Clark, 1997). CONCLUSIONS AND RECOMMENDATIONS The trees on this site are 50+ years old and have exceeded the average life expectancy of the species. Extensive white rot and hollowed root collar was observed in the stump of a recently removed tree, resistograph testing of the remaining 11 trees shows most have moderate to advanced decay in the root collars. The lack of response wood suggests the decay is spreading faster than the tree can respond to its spread. While not all trees are high risk at this time, nor do they all need to be removed immediately, it is likely that most will need to be removed over then next 5-10 years. A number of the trees would require cabling and deadwood removal if they where to be retained for the short-term. While the homeowner has enjoyed these trees, and the benefits they have provided for several years, they are willing to remove the trees to mitigate the hazards associated with their retention, and replant with 11 new trees appropriate to the site. This make more sense and is likely the best management plan, rather than putting a lot of time and finances into trees that will need to be removed in the near future. Due to root/trunk decay tree failure, in the weather events common to our region, is possible, should a tree fail, it will hit a target and cause significant damage. Currently, using the ISA Risk Matrix, the trees are Low to Moderate risk. Over time, as the decay spreads, tree failure potential will exponentially increase as will their Risk Rating. Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 6 of 19 Recommendation As there is no way to stop the spread of decay and no reasonable, long-term way to mitigation the risks associated with the retention of the trees, it is my professional opinion, that the trees are over mature and have out lived their life expectancy and my professional recommendation is that the trees be removed before the next significant weather event, or at a minimum in the following time frame. Recommendation Time Frame Trees 4, 6, 7, 8, remove 0-6 months Trees 1, 2, 3, remove 2-3 years Trees 9, 10, 11 remove 3-5 years Tree 5 remove 5-years Any tree not being removed in 2018 should have any deadwood and weak limbs removed and any co- dominate trunks should be cabled with cobra cabling system per ANSI A300 part 3 standards. Thank you for contacting A.B.C. Consulting Arborists LLC for your arboricultural needs. Sincerely, Daniel Maple, Consulting Arborist Registered Consulting Arborist #627 ISA Municipal Specialist #PN-7970AM ISA Tree Risk Assessment Qualified (TRAQ) ISA Board Certified Master Arborist #PN-7970BM Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 7 of 19 WAIVER OF LIABILITY Assumptions & Limiting Conditions 1. A field examination of the site was made for this report (date referenced in report.) Care has been taken to obtain all information from reliable sources in a timely fashion. Therefor all data has been verified to the best of my knowledge, the certified/consulting arborist can neither guarantee or be held responsible for the accuracy of information provided by any outside sources. 2. All information provided in this report covers only the tree’s that were examined and reflects the condition of those tree(s) at the time of inspection. This inspection is limited to a visual method of the trees in question, excluding any core sampling, probing, dissection, aerial inspection, or excavation unless noted in writing and contingent upon the appropriate fee being authorized in writing. There is no guarantee nor warranty, expressed or implied that any deficiencies or problems of the mentioned trees may not arise in the future. 3. All drawings, sketches, and photographs submitted with this report, are intended as visual aids only, and are not exact to scale. They should not be construed as engineering or architectural report of surveys unless noted and specified. 4. The certified arborist/consulting arborist is not required to give any testimony or to attend court for any reason considering this report unless subsequent contractual agreements are made. 5. Any alterations made to this report or loss automatically invalidates this report. 6.This document is protected by copy right laws©. Unless required by law otherwise, possession of this report or a copy of this report does not imply right of publication or use for any purpose by anyone other than the person for whom it was created for, without prior expressed written permission and verbal consent of the consulting arborist. 7. The report and values/opinions expressed, represent the opinion of the certified/consulting arborist, and the arborist fees are in no way contingent upon reporting any specified values, stipulated results, the occurrence of a subsequent event, nor upon finding to be reported. ATTACHMENTS Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 8 of 19 ATTACHMENT 1 - TREE PLOTTER IMAGES ................................................................................. 9 ATTACHMENT 2 - PHOTOS .............................................................................................................. 10 ATTACHMENT 3 - TREE RISK ASSESSMENT SUMMARY ........................................................ 12 ATTACHMENT 4 - RESISTOGRAPH® TEST RESULTS .............................................................. 13 ATTACHMENT 5 - REFERENCES .................................................................................................... 18 Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 9 of 19 ATTACHMENT 1 - TREE PLOTTER IMAGES Site Map Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 10 of 19 ATTACHMENT 2 - PHOTOS Photo 1 Photo 2 Photo 3 Photo 4 Evaluation of Koch Trees, Renton WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 11 of 19 Photo 5 Photo 6 Recently cut tree between #6 & #7 Note Advanced Decay Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 12 of 19 ATTACHMENT 3 - TREE RISK ASSESSMENT SUMMARY Id Common Name Latin Name DBH Height Spread Roots - Decay Testing Method Test Results Risk Rating Mitigation Comments Action 1 Lombardy Poplar Populus nigra 60 100 48 Drill & Resistograph Hollow Moderate Advanced decay/hollow center. Maybe viable for few years. Not worth the risk. BMP Remove. Remove 2-3 years 2 Lombardy Poplar Populus nigra 49 100 42 Drill & Resistograph Hollow Moderate Advanced decay/hollow center. Maybe viable for few years. Not worth the risk. BMP Remove. Remove 2-3 years 3 Lombardy Poplar Populus nigra 40 100 37 Drill & Resistograph Hollow Moderate Advanced decay/hollow center. Maybe viable for few years. Not worth the risk. BMP Remove. Remove 2-3 years 4 Lombardy Poplar Populus nigra 36 100 33 Drill & Resistograph Hollow Moderate Advanced decay/hollow center. Remove. Remove 0-6 months 5 Lombardy Poplar Populus nigra 34 100 37 Drill & Resistograph Incipient Decay Moderate Wood is discolored with beginning stages of decay. Likely viable for 5-years. Install cobra cable. Or remove due to history of decayed root collars Remove 4-5 years or Cable 6 Lombardy Poplar Populus nigra 37 100 35 Drill & Resistograph Hollow Moderate Advanced decay /hollow center. Failure possible to probable remove soon. Remove 0-6 months 7 Lombardy Poplar Populus nigra 34 100 35 Drill & Resistograph Hollow Moderate Advanced decay /hollow center. Failure possible to probable remove soon. Remove 0-6 months 8 Lombardy Poplar Populus nigra 27 100 22 Drill & Resistograph Decay Moderate Moderate decay and dying. BMP remove Remove 0-6 months 9 Lombardy Poplar Populus nigra 21 90 16 Drilling Decay Low Minor decay. Short term viable. Retain or remove 3-5 years 10 Lombardy Poplar Populus nigra 18 70 12 Drill & Resistograph Decay Low Minor to moderate decay. Leaning at building. Suppressed poor-fair health. Not long term viable Retain or remove 3-5 years 11 Lombardy Poplar Populus nigra 47 100 35 Drill & Resistograph Decay Moderate Low failure at this time. Minor/moderate decay. BMP could be remove. Could cable retain and monitor. Not long-term viable Cable / Retain OR Remove 3-5 years Following the mitigation actions, the residual risk will be low to none. Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 13 of 19 ATTACHMENT 4 - RESISTOGRAPH® TEST RESULTS Tree 1 Tree 2 Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 14 of 19 Tree 3 Tree 4 Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 15 of 19 Tree 5 Tree 6 Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 16 of 19 Tree7 Tree 8 Tree 9 Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 17 of 19 Tree 10 Tree11 . Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 18 of 19 ATTACHMENT 5 - REFERENCES 1. Arno, Stephen F. and Hammerly, Ramona P. Northwest Trees. Anniversary Ed. Seattle, Washington: The Mountaineer Books, 2007. 2. Brockman, C. Frank, Trees of North America, A Guide to Field Identification. New York: Golden Press, 1979. 3. Dunster, Dr. Julian A., R.P.F., M.C.I.P. Documenting Evidence, Practical Guidance for Arborists, First Choice Books, Victoria, BC, Canada. 2014. 4. Dunster, Dr. Julian A., R.P.F., M.C.I.P. Interpreting Resistograph Readings, A Manual for Users of the Resistograph Decay Detection Instrument. Bowen Island, Canada: Dunster & Associates, 2000. 5. Eric Allen, et al. Common Tree Diseases of British Columbia. Victoria: Canadian Forest Service, 1996. 6. Harris, Richard W, James Clark, and Nelda Matheny. Arboriculture, Integrated Management of Landscape Trees, Shrubs, and Vines. 4th ed. Upper Saddle River: Prentice Hall, 2004. 7. Jacobson, Arthur Lee. Trees of Seattle. 2nd ed. Seattle, Washington: Arthur Lee Jacobson, 2006. 8. Johnson, Warren T. and Lyon, Howard H. Insects That Feed on Trees and Shrubs. Ithaca: Comstock Publishing Associates, 1991. 9. Kershner, Bruce; Mathews, Daniel; Nelson, Gil; and Spellenberg, Richard. National Wildlife Federation Field Guide to Trees of North America. New York: Chanticleer Press, 2008. 10. Link, Russell, Landscaping for Wildlife in the Pacific Northwest, The University of Washington Press, Seattle, WA. 1999. 11. Matheny, Nelda P. and Clark, James R. Evaluation of Hazard Trees. 2nd ed. Savoy: The International Society of Arboriculture Press, 1994. 12. Matheny, Nelda P. and Clark, James R. Trees & Development, A Technical Guide to Preservation of Trees During Land Development. Savoy: The International Society of Arboriculture Press, 1998. 13. Mattheck, Claus and Breloer, Helge. The Body Language of Trees, A Handbook for Failure Analysis. London: HMSO, 1994. 14. Pacific Northwest Chapter-ISA. Tree Risk Assessment in Urban Areas and the Urban/Rural Interface. Course Manual. Release 1.5. PNW-ISA: Silverton, Oregon, 2011. 15. Scharpf, Robert F. Diseases of Pacific Coast Conifers. Albany, California: USDA Forest Service, Agriculture Handbook 521, rev. June 1993. Evaluation of Koch Trees Renton, WA. By, A.B.C. Consulting Arborists LLC May 11, 2018 Page 19 of 19 16. Seattle Department of Planning and Development, Client Assistance Memo CAM 242, Tree Regulations in Seattle. Updated September 8, 2006. 17. Seattle Department of Planning, (DPD), Director’s Rule 16-2008, Designation of Exceptional Trees. Publication October 16, 2008. Effective April 1, 2009. 18. Sinclair, Wayne A., Lyon, Howard H., and Johnson, Warren T. Diseases of Trees and Shrubs. Ithaca, New York: Cornell University Press, 1987. 19. Smiley, E. Thomas, Nelda Matheny, and Sharon Lilly, Tree Risk Assessment Best Management Practices, ANSI A300 Part 9: Tree, Shrub, and Other Woody Plant Management—Standard Practices (Tree Risk Assessment a. Tree Structure Assessment). The International Society of Arboriculture Press. Champaign. IL. 2011. 20. Watson, Gary W., and Neely, Dan, eds. Trees & Building Sites. Savoy: The International Society of Arboriculture Press, 1995.