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HomeMy WebLinkAboutPWD-030-21Clarington Staff Report If this information is required in an alternate accessible format, please contact the Accessibility Coordinator at 905-623-3379 ext. 2131. Report To: General Government Committee Date of Meeting: November 29, 2021 Report Number: PWD-030-21 Submitted By: Stephen Brake, Director of Public Works Reviewed By: Andrew C. Allison, CAO Resolution#: GG-511-21, C-406-21 File Number: By-law Number: Report Subject: Arborist Review of Red Oak Tree at 21 Beech Avenue Recommendations: 1. That Report PWD-030-21 and any related communication items, be received; 2. That Council provide staff with approval to carry out the tree preservation plans provided in the review completed by Del Cressman for the red oak tree at 21 Beech Avenue; 3. That the recommended tree preservation plan be funded from the Self -Insured Losses Reserve at an estimated year -one cost of $12,000; and 4. That all interested parties listed in Report PWD-030-21 and any delegations be advised of Council's decision. Municipality of Clarington Report PWD-030-21 Report Overview Page 2 This report addresses Council Resolution C-227-21, passed on July 5, 2021, that referred the matter of the red oak tree at 21 Beech Avenue back to staff to look at the option suggested by Mr. and Mrs. Clermont during their delegation. The suggestion was for Mr. Dell Cressman of Cressman Tree Maintenance and Landscaping Ltd. to review both existing arborist reports and that he submit a quote for the services he recommends. Resolution C- 227-21 also requested that a survey be completed of the red oak tree location to determine the exact property boundaries. 1. Background 1.1 On June 21, 2021, Staff submitted Report PWD-025-21 to General Government Committee. The report requested Council's direction to implement the recommended tree preservation plan prepared by Arborist Michael Richardson of Richardson Tree Care for the red oak tree located at 21 Beech Avenue. The tree preservation plan recommends pruning, soil invigoration and a limb support system using poles and cables at an upset cost of $56,100. A copy of the Generalized Tree Preservation and Pricing Report dated April 19, 2021 by Mr. Michael Richardson is provided as Attachment 1. 1.2 At the regular Council meeting held on July 5, 2021, delegations were made by Stephen Brickell, Mark Clermont and Darlene Clermont regarding Report PWD-025-21. Mr. and Mrs. Clermont are the homeowners of 21 Beech Avenue. During their delegation, the Clermont's advised that they too had hired a master arborist to assess the conditions of the red oak tree. In their arborists report, prepared by Ruurd van de Ven of Van de Ven Consulting Group, the tree preservation plan recommends pruning and the use of a cable support system only. The cost of the 7-year preservation plan provided by Mr. van de Ven is estimated to cost between $12,000 and $18,000. A copy of the Arborist Report prepared by Mr. van de Ven dated May 18, 2021, is provided as Attachment 2. 1.3 At the regular meeting held on July 5, 2021, Council passed Resolution C-227-21 that referred the matter of report PWD-025-21 back to staff. The suggestion proposed by the Clermont's requested that Del Cressman, I.S.A. Board Master Certified Arborist, review both arborist reports and that he submit a quote for the services he recommends. Resolution C-227-21 also requested that staff obtain a survey of the tree location to determine the exact property boundary lines. Municipality of Clarington Report PWD-030-21 2. Analysis Page 3 2.1 In the days following the July 5, 2021, Council meeting, staff reached out to Mrs. Clermont to discuss the direction that was provided in Resolution C-227-21 and also to confirm the Municipality's proposed plan of action. 2.2 On August 10, 2021, a formal request was made for Mr. Del Cressman of Cressman Tree Maintenance & Landscaping Ltd. to complete a third -party review of the two existing arborist reports and to recommend a tree preservation plan. 2.3 On October 15, 2021, Mr. Cressman submitted his review. The recommended tree preservation plan includes a three -step approach that includes the pruning of the tree to reduce the size of the crown, the installation of a cabling program only and the provision of a deep root fertilizing of the tree. These specific treatments follow the general recommendations of the report submitted by Mr. Ruurd van de Ven at an estimated cost of $12,000 in the first year. A copy of the review completed by Mr. Cressman is provided as Attachment 3. 2.4 Mr. Cressman has indicated that he believes the balance of the 150- to 200-year-old red oak tree can be preserved. Work, however, needs to begin immediately on the preservation plan with a commitment to follow-up with on -going inspections, pruning's and fertilizations. The costs associated with future maintenance is expected to be an additional $10,000 spread over the next six years. 2.5 Staff also retained IBW Surveyors to complete a survey of the tree location at 21 Beech Avenue. The completed sketch confirms that 1.04 m of the tree's diameter is situated on private property while 1.18 m exists within the public road right-of-way. A copy of the sketch prepared by IBW dated September 3, 2021, is provided as Attachment 4. 3. Concurrence This report has been reviewed by the Director of Financial Services/Treasurer who concurs with the recommendation for the source of funding. 4. Conclusion It is respectfully recommended that Council provide approval for staff to implement the tree preservation plans presented by Mr. Del Cressman for the red oak tree at 21 Beech Avenue. It is also requested that Council provide support the proposed future tree preservation requirements that include on -going tree inspections, pruning and fertilizations as part of staff's regular work plan and annual budget request. Municipality of Clarington Report PWD-030-21 Staff Contact: Stephen Brake, Director of Public Works, 905-623-3379 ext. 2903 or sbrake@clarington.net Attachments: Attachment 1 — Generalized Tree Preservation and Pricing (Richardson Tree Care) Attachment 2 — Arborist Report (Van de Ven Consulting Group) Attachment 3 — Review of Arborist's Reports (Cressman Tree & Landscaping Ltd.) Attachment 4 — Red Oak Tree Sketch — 21 Beech Avenue (IBW Surveyors) Interested Parties: The following interested parties will be notified of Council's decision: Clarington Heritage Committee Rick McEachern 1► FTi:�:�l�FTiC�iT�y-[�i"'�tiliii Page 4 iY I - • - ...w, 79 . mil••"_ .� tS ..�a •.; �-3 .8 �Y -.1 .� rim" Richardson Tree Care P.O. Box 8. Brighton, Ontario KOK 1 HO April 19, 2021 Ken Mercer Supervisor Public Works Department Municipality of Clarington 40 Temperance Street, Bowmanville ON L1 C 3A6 905-623-3379 ext. 2945 KMercer(a-).clarington.net Re: Beech Street Oak Tree This pricing is a generalized guide for the retention of the oak tree at 21 Beech St., Bowmanville. It does not provide specific prices but rather provides a guide to understand the cost of retaining the tree using wooden utility poles. The assumption is that this methodology is acceptable but it is expected an engineer is needed to verify the size and suitability of various portions of the system. The subject tree is 186 cm diameter red oak on the front lawn/municipal road allowance at 21 Beech St. The tree is approximately 230 years old and can certainly live for another 50 years if cared for. The primary issue with the tree is the two lowest, over- extended, heavy limbs that are at risk of failure. Secondarily other limbs are at risk of failure. The primary mechanism for short term retention is to support limbs using a combination of utility poles supporting the limbs and cabling the limbs to the pole. Pruning of the tree shall be done to remove deadwood and reduce the size of the tree. It is hoped that new interior growth can be encouraged and the tree can be further reduced in the future. Morpho-physiological Age of Trees Young maturing phase: Early to late maturity: Early-, mid- & late -ancient Apical dominance Lower units break free from phases: crown retrenchment & apical dominance reiterative growth (a) F N (h) t) O 0 0 '�.J (2� Trees do not have a finite lifespan but rather are subject to the strains of their site and grow larger to an ultimate size then reduce in size and hollow. This is a fully natural process and we can hope to prolong the life of a tree, and manage risk, by reducing the size of the tree and supporting it where necessary. The tree is at approximately stage 7/8. The hope is to support the limbs, allow new interior growth and reduce the tree over the next 20 to 50 years. The largest limb over the road is to be supported by two poles. The shorter one will support the distal end while the taller pole will support the proximal end and be used to cable limbs to. P1 it i a 'Y]7Yb � I f yam' ''x . • bSaAC-.': ' - ... f FAin t'�af IL — ems_ - - - _ �-'.'�%'•. _ -7,�•' `Z' i_ ♦ '` �p, } fF ,r F`'�r £� � � • s � f � � � ���` �� � , � his,. ` b '"•� Sequence of steps 1) Decide on preservation path based on price, feasibility, risk management, homeowner, residents etc. 2) Design support system based on: a. Locates b. Engineering as required c. 21 Beech St homeowner agreement, ability to place poles d. Tree components to be supported 3) Prune Tree a. Remove all deadwood >5cm diameter b. Reduce limbs by 3-4 in length to allow sunlight to penetrate and encourage reiterations c. Tree pruning to be supervised by Michael Richardson to achieve goals of crown reduction and to initiate new interior growth d. Tree pruning to be done by a company that meets standards for pruning set by Michael Richardson (thus companies specializing in tree removal and utility line clearing may not be able to provide proof of pruning knowledge and experience required) 4) Locate Poles on site 5) Hydrovac holes a. Hydrovac company shall be chosen by pole install company b. Water pressure shall be reduced to avoid damage to roots c. Hydrovac shall be supervised by Michael Richardson 6) Install poles a. A utility company will do this b. Pole installation shall be supervised by Michael Richardson 7) Install cross braces if needed a. Pole installation company can do this 8) Install cabling a. Cable limbs to pole using approved hardware b. Cabling shall be supervised by Michael Richardson 9) Soil invigoration a. Reduce soil compaction and introduce fish fertilizer into soil b. Develop prescription to encourage reintroduction of organic matter into soil. c. Mulch boulevard with wood chips 10) Yearly monitoring 11) Further pruning, likely year 8--10 Generalized costs These costs have been estimated by talking to suppliers and contractors. Prices are estimates only and will change based upon the specifics. In particular the costs of engineering, poles, and cabling hardware will be determined once a formalized plan is developed. Design of support System, create detailed pruning specifications, gather quotes etc. (Michael Richardson) $1500 Engineering of Support System $5000? Deadwood & Pruning $3000 Supervision of Pruning (Michael Richardson) $800 Poles 2-75 H1 poles $8500/pole 1-30 $2500 1-25 $2500 $23000 Hydrovac $3500 Supervision of Hydrovac (Michael Richardson) $500 Pole Install $3500 Supervision of Pole Install (Michael Richardson) $800 Cabling Equipment $7500 (likely high) Cabling labour 4000 Supervision of Cabling (Michael Richardson) 1000 Soil invigoration — can be delayed 2000 Locates Free? Specific Costs If you wish to proceed, we can begin the process of developing a specific plan, quantifying materials and obtaining quotes. Signed Michael Richardson, B.Sc.F., ISA BCMA ON-0377B Ontario MTCU Qualified Arborist Butternut Health Assessor # 472 Attachment 2 to Report PWD-030-21 Arborist report 21 Beech Ave, Bowmanville Ruurd van de Ven, ISA BCMA VAN DE VEN CONSULTING GROUP vandevengroup@gmail.com 905 955 4856 For: Mark and Darlene Clermont Van de Ven Consulting Group 905-955-4856 Introduction There was a limb failure in the oak tree located on 21 Beech Ave in Bowmanville on June 30, 2020, this resulted in questioning the safety of this tree. The assignment was to assess the tree for health as well as the risk associated with this tree. The report was created to describe mitigation that can be used to preserve this tree and maintain it for the future. Observations Investigation methods The method of investigation did not include any probative methods other than measuring the depth of cavities with a measuring tool such as is used to measure depth of tiles in an agricultural field. This is a fiberglass tool about 125 cm long and 12 mm in diameter. This tree was climbed in the process of the assessment and photographs were taken for documentation. A tree risk assessment was performed to determine the risk that this tree poses to the immediate surroundings. When assessing trees, the parts of the trees that are at risk of causing damage or injury are assessed using various methods. In this instance only visual ques were used in the assessment as well as the assessor's knowledge and experience with this species of tree. The initial investigation was performed on July 4, 2020 with a subsequent visit to the property on May 11, 2021 for additional photographs. Site and Field Observations The location of this tree is in the front yard of 21 Beech Ave, a historic neighborhood in the Town of Bowmanville. The sidewalk runs under this tree and the base of the tree is right at the sidewalk. There is a small boulevard between the sidewalk and the roadway. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Subject Tree Observations This red oak (Quercus rubra) is 193 cm in diameter measured 140 cm from the ground (DBH). The diameter of this tree just below the first branches at 335 cm above the ground is 204 cm and the diameter above the first branches at 490 cm above the ground is 164 cm. A large limb had broken off this tree on June 30, 2020, the limb that broke off left a wound on the trunk measuring 60 cm in diameter. This had broken away from the trunk leaving a 40 cm gap in behind. There was some decay in this gap. Two areas of reaction wood have formed at the underside of this limb (compression wood) . The photograph to the left shows the wounds as well as the two areas of reaction wood at the bottom of this limb. This tree is approximately 20 m tall and has a crown spread of about 50 m. This tree has some very long over extended limbs in the lower half of the tree. One limb is over the traveled portion of the road. This limb extends 24 m over the road and where the limb is attached to the tree it is 69 cm in diameter. This long limb over the road has an oval shape with a substantial amount of reaction wood on the top side of this branch (tension wood). RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Expert Opinion & Observations The age of this tree is not known exactly, however the surrounding homes were built about 150 years ago thus I would surmise that this tree is at least 150 years old, possibly older. An extensive study using Rinntech Arbotom° Sonic Tomography and Rinntech Resistograph°. Was done by Mr. Michael Richardson and described in a report dated September 22, 2020. This report shows there is some decay in the trunk resulting in a 9% strength loss. Discussion Red oak trees are part of the angiosperm group of plant in other words they are flowering plants that bear fruit covered seeds, whereas gymnosperm (conifers)bare uncovered seed. They are a long lived native species of tree that has played a great role in providing food for the native aboriginal population as well as lumber used mostly in the making of furniture. Its native range is from eastern Canada, Ontario, Quebec, Atlantic provinces to south eastern United States into Georgia and Louisiana. Longevity Red oak is very resistant to decay and can live very long even in the adverse environment such as this suburban location. As indicated earlier it is my opinion that this tree is at least 150 years old, possibly as old as 200 years. It is at the height of its maturity and from here on forward it will start to decline naturally. No sign of decline was observed at this time, but as trees age they will become smaller in stature byway of limb mortality in the top of the crown and at the end of the limbs, thus reducing their size and preserving the amin structure of the tree. Trees such as this could possibly live to be 250-350 years old given the right conditions and the least amount of urban disturbance. Mature tree pruning Tree pruning is considered a good maintenance practice, ANSI A300 pruning standard allows no more than 25% of live tissue removed from a tree. To maintaining mature and over mature trees, our thinking about pruning needs to be revised, these trees need as much of their canopy to keep their stored food reserves up and if too much live material is removed the tree could decline. This tree has some very large limbs that will need to be reduce in length to prevent failure of the limbs. One limb over the road is posing the highest risk currently. Reduction of this limb will result in the removal of about 10% of live tissue. Tree engineering Angiosperms create reaction wood on top of branches away from the force that is working on it. In this case gravity is pulling the limbs down to the ground so the tree has formed tension wood on top of the branches to help hold them up. The cell structure in this portion of the limb is different and stronger than the rest of the cells and thus it helps in keeping the branches in place. This tree in addition to forming tension wood it has also developed some compression wood at the base of the limb that has RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 failed. Here the compression wood was holding the branch in place until it ultimately failed. Not due to the limb failing but due to the branch union failing. Risk assessment The failure of the limb over the house can be contributed to two main factors, poor attachment to the tree and excessive weight of the limb. Since this tree had not been maintained for many years, this condition was allowed to continue and over time a failure such as this will occur. Very old pruning wounds can be seen throughout the canopy. These large wounds indicate that when the tree was pruned last an attempt was made to reduce the canopy. The risk assessment of this tree does indicate that in its current state this tree is a moderate risk of failure. If left unattended that large limb over the road will eventually fail and could potentially cause damage or injury. Risk assessment looks at a variety of factors in determining the risk of a tree part failing and that tree part doing damage or personal injury. The surrounding area where a tree is growing will determine the likely hood of a failed part causing damage or injury. In this situation the tree is located at the front of a private residence along a public road with a sidewalk. The public road is in a quiet neighborhood, it does support through traffic but mostly only for those living in the area. Therefore, the likelihood of damage and/or injury is not as high as if the tree would be located on a busy through fare. Likelihood of failure considers normal weather conditions for the area. Trees generally will not fail under calm weather conditions, there is usually a combination of tree defects and adverse weather that will cause a failure. Current risk situation: This tree if left unattended will probably fail in the next 5-7 years. This in combination with a severe likelihood of damage and/or injury results in a moderate risk for this tree. Risk after mitigation: prune to reduce the weight and length of the limb over the road as well as some other limbs in this tree; the installation of a cabling system for support of the long limbs. The likelihood of failure will be reduced to possible in the next 5-7 years, thus reducing the risk for this tree to low. Health Health and structure in trees are two separate items. A tree can be very healthy and structurally unsound to the point it will need to be removed, conversely a tree can be almost dead structurally very sound. This tree appears to be healthy and growing well. Pruning will reduce the ability for the tree to produce needed elements for proper tree growth. Soil where a tree grows contributes to a trees well- being, it provides nutrients and moisture. Improving the soil conditions will keep trees healthy. Soil improvement should include adding organic matter and possibly some nutrients. By adding organic matter we will increase the soil biology and this increases the availability of nutrients to the tree. Conclusions Maintaining trees is an ongoing exercise and with older and veteran trees this needs to be handled with care and a delicate balance between risk to the community and the well being of the tree. If the risk of RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 keeping a tree becomes too great it may need to be removed, however there are many mitigation options available to preserve the old veteran trees and keep a safe neighborhood. Veteran trees such as this red oak represent our past and binds heritage communities together. It is important to maintain these assets of the community. Recommendations Mitigation for reducing the likelihood of damage or injury from this tree will require a multi -pronged approach. • Traffic reduction: Reducing the amount of time spent by the public underneath this tree will greatly reduce the risk of damage and or injury. o Making this street one way o Creating a no parking zone under the tree o Removing the sidewalk and installing a new sidewalk in the west side of the road. • Pruning: Older trees require a delicate touch when it comes to pruning. Too much pruning will hurt the tree and, in this case, not enough pruning will not provide the desired results. Therefore, I am proposing to do the pruning in two stages as a significant amount of live branches will need to be removed to reduce the risk on this tree. Year 1 o Removal of all deadwood 2 cm and larger in the crown of the tree; o The long limb over the road should be cut back to reduce the weight and the length of it. Reduction cuts for this limb shall be no larger the 25 cm. o The accompanying photographs indicate the propose location of the reduction cuts. • The limb growing to the south over the lawn shall be thinned and only reduced slightly. Reduction cuts for this limb shall be no larger than 5 cm. Year 2-3 • Evaluation of the tree to monitor for any decline; o Based on evaluation suggest further reduction pruning: ■ The limb to the south shall be reduced further. Reduction cuts for this limb shall be no larger the 25 cm Year 4-6 o Monitor tree for decline and visually inspect cabling system Year 7 o Removal of deadwood and pruning to further reduce the weight of limbs throughout the tree. Removal of life material shall be no more than 15%. Continued pruning once every 5-7 years as needed to remove deadwood and reduce weight. Cabling: The long limbs in this tree can be supported with a cabling system. This will be in addition to the limb reduction. The cables are there to help support the limbs but also in case of a limb failure the cables are more likely to keep the limbs from falling to the ground. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Specifications Pruning: This document is to be used as a specification for the pruning of the red oak located in the front yard of 21 Beech Ave, Bowmanville. The work is to be carried out in accordance with the specifications set out her in which follow the ANSI A00 standard This work is to be carried out by ISA certified arborists. Objective: This veteran tree has some very long limbs that will need to be reduced. No more than 15% of live tissue can be removed at any one time over a period of 2 years. Branches: Year 1 o Removal of all deadwood 2 cm and larger in the crown of the tree; o The long limb over the road should be cut back to reduce the weight and the length of it. Reduction cuts for this limb shall be no larger the 25 cm. o The accompanying photograph indicate the proposed location of the reduction cuts. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 The limb growing to the south over the lawn shall be thinned and only reduced slightly. RUURD VAN DE VEN, ISA BCMA 'yi3 'i1•r 4 . t . Sfyr �� . BY°i�` ' �,• '��1 q� � ,;tee OR �MWWZ.,_ A Van de Ven Consulting Group 905-955-4856 Year 4-6 o Monitor tree for decline Year 7 Removal of deadwood and pruning to further reduce the weight of limbs throughout the tree. Removal of life material shall be no more than 15%. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Cabling: This document is to be used as a specification for the cabling of the red oak located in the front yard of 21 Beech Ave, Bowmanville. The work is to be carried out in accordance with the specifications set out her in which follow the ANSI A00 standard This work is to be carried out by ISA certified arborists. The cabling system will require annual inspection, This is a visual inspection from the ground. Once every 5-7 years when the tree is pruned the system will need a closer inspection. Objectives: This tree has some very long limbs that will benefit from the installation of a cabling system. System: o The systems shall be installed to the ANSI A300 Standard (Part 3) supplemental support systems. o The system shall employ through bolts and Amon eye nuts or eyebolts 5/8" in diameter o The system shall employ Extra high strength cable 7/16" in diameter of Aircraft cable %" in diameter. o The system, shall be installed in the approximate location as indicated in the photograph. This location shall be confined on site in consultation with the consultant RUURD VAN DE VEN, ISA BCMA 10 Van de Ven Consulting Group 905-955-4856 Budget Pruning: Year 1 o Removal of all deadwood 2 cm and larger in the crown of the tree; o The long limb over the road should be cut back to reduce the weight and the length of it. Reduction cuts for this limb shall be no larger the 25 cm. o The limb growing to the south over the lawn shall be thinned and only reduced slightly. Reduction cuts for this limb shall be no larger the 5 cm. ■ $4000.00 Year 2-3 o Evaluation of the tree to monitor for any decline; o Based on evaluation suggest further reduction pruning: ■ The limb to the south shall be reduced further. Reduction cuts for this limb shall be no larger the 25 cm ( in red) ■ $4000.00 Year 4-6 o Monitor tree for decline ■ $5-800.00 annually Year 7 o Removal of deadwood and pruning to further reduce the weight of limbs throughout the tree. Removal of life material shall be no more than 15%. Cabling: System: o The systems shall be installed to the ANSI A300 Standard (Part 3) supplemental support systems. o The system shall employ through bolts and Amon eye nuts or eyebolts 5/8" in diameter o The system shall employ Extra high strength cable 7/16" in diameter of Aircraft cable %" in diameter. o The system, shall be installed in the approximate location as indicated in the photograph. This location shall be confined on site in consultation with the consultant ■ $3-8000.00 Annual inspection to be done as part of regular maintenance when tree is pruned. RUURD VAN DE VEN 1 Attachment 3 to Report PWD-030-21 CRESSMAN TREE MAINTENANCE & LANDSCAPING LTD. P.O. Box S7, Cobourg, ON K9A 4KZ October 15, 2021 Municipality of Clarington 40 Temperance Street Bowmanville, Ontario L1C 3A6 Attention: Steve Brake and Ken Mercer By email to: sbrake@clarington.net and kmercer@clarington.net RE: Review of Arborist's Reports for 21 Beech Street, Bowmanville, Ontario As requested, I have reviewed the Arborist's Reports as prepared by Michael Richardson and Ruurd van de Ven. I have also visited the site and observed the tree from the ground. The following are my observations from the two reports and my recommendations. OBSERVATIONS: 1. From Michael Richardson: The Tomogram Cross-section on page 10 shows an intact wall of live, solid wood and the Resistograph Drilling confirmed the same. This was done one metre above the ground but from my observations, I believe that this characterizes the entire trunk, up into the crown. Therefore, the structural stability of the trunk is not in question. Michael also mentions this on page 7 of his report when referring to the large limb that did fail. He said, "The cavity within the trunk played no role in the failure". I would agree with that statement. 2. Both reports indicate the current risk is with the two long, heavy limbs; one on the west side and one on the south side. I would agree. The union of the two limbs with the trunk both have included bark which creates weakness and the possibility of failure. Both limbs, as noted in the report by Ruurd van de Ven, have developed Tension wood and Compression wood. This is the tree's way of supporting the weight of the limb. Neither limb, from my observation and from the pictures in Michael Richardson's report, indicate that the unions have begun to fail. So, the question is: how can we preserve the tree and reduce the risk of failure? From research over the past 20 years or more, in the Arboriculture industry, we have learned that when you reduce the weight at the end of long, heavy limbs, you substantially reduce the stress on the limb and trunk union. From my experience, this is true. I have preserved many mature trees by reducing the size of the crown, installing cabling to help support the limbs, and by deeproot fertilizing. I know of mature trees that have been preserved for 20 to 40 years, however this is achieved with a long-term commitment, not a "one and done" procedure. RECOMMENDATION: I believe that this Red Oak can be preserved for many years to come. Firstly, I recommend the pruning program as proposed on pages 5 to 8 in the report prepared by Ruurd van de Ven. The goal will be to reduce the size of the crown starting with shortening back the west and south sides, as shown on pages 6 to 8 in the report, with proper drop crotch pruning. I would also recommend that no branches be removed from the inner crown of the tree. My hope is that we encourage more growth in the inner crown so that, in the future, we could shorten back the two P-905-372-3801 F-905-372-2413 C-905-377-5286 Email: off ice@cressmantreelandscape.ca large, heavy limbs even more thus improving the overall health and structure of the tree for many years to come. Secondly, I recommend the cabling program as proposed on page 10 of the report prepared by Ruurd van de Ven. With the installation of cables, the west limb will be supported, however proper positioning of the cables is critical. Finally, I recommend that the tree be deeproot fertilized using WIN Tree 30-8-8 fertilizer by Plant Products, as per the attached data sheet. This would be applied to as much of the root area as possible and be repeated every 2 to 3 years. As Michael and Ruurd have suggested, this Red Oak is approximately 150 to 200 years old. It is a magnificent tree and it, along with several other mature trees, are a significant part of the heritage and character of the street. I wish we would have started pruning for crown reduction and cabling on this tree 30 years ago because we probably wouldn't have lost the large limb on the east side. But I believe the balance of the tree can be preserved, however, we need to start the preservation plan now and be committed to follow-up with ongoing inspections, prunings and fertilizations. I trust this review will be of value to you. Feel free to call me with any questions or concerns. Yours truly, Del Cressman, President I.S.A. Board Master Certified Arborist ON-0183 Attachments: - Pages 7 & 10 from the report prepared by Michael Richardson - Pages 5-9 (Pruning) from the report prepared by Ruurd van de Ven - Page 10 (Cabling) from the report prepared by Ruurd van de Ven - WIN Tree fertilizer data sheet Red Oak, 21 Beech St., Bowmanville Draft 1 Page 7 of 28 The tree has begun to segment into functional units. This means that a functional unit of a distinct section of the tree consisting of a limb or branch with associated foliage, a portion of the trunk and roots connected through a buttress roots has formed that is acting independently of the rest of the tree. This is particularly evident on the two lower limbs. If a functional unit is over -pruned or the limb completely removed the associated stem and roots will die. Failure Mode Assessment of the Failed Limb The failed limb fractured because there was no integration of the branch fibers into the trunk on the upper portion of the of limb combined with the weight applied to the long lever arm. This is a very common failure mode in large oaks. The cavity within the trunk played no role in the failure. There are very well -formed growth ribs on the underside of the failed limb. The large growth ribs are pushing the limb up but the traditional tension mode of angiosperms was lost many years ago on this limb. There is no connection between the limb and the trunk on the upper half of the limb. This is identified by included bark, the loss of the branch bark ridge. Near vertical apparent connection interface, and in the photo of the fracture the loss of toothpick like fibres above the fracture line. f. x i fr. A10 ©Michael Richardson, B.Sc.F., BCMA, MTCU Qualified Arborist September 22, 2020 Red Oak, 21 Beech St., Bowmanville Draft 1 Page 10 of 28 5 :f= s� I�• e I��'• `tJ ti _i i� 1' S �I�Ji i.iFS � I Tomogram of Cross-section Shown in Above Photograph P'WI B—b 9i ems .. A, 7IN& n.. mn4M �M1•ym iRf� W4Y' ry= M un �M 1 I I I I I I I I I I 1 i i i � ....L A._._ loco- I I i I i I � i 1 i 791 em 7a' ©Michael Richardson, B.Sc.F., BCMA, MTCU Qualified Arborist September 22, 2020 Van de Ven Consulting Group 905-955-4856 keeping a tree becomes too great it may need to be removed, however there are many mitigation options available to preserve the old veteran trees and keep a safe neighborhood. Veteran trees such as this red oak represent our past and binds heritage communities together. It is important to maintain these assets of the community. Recommendations Mitigation for reducing the likelihood of damage or injury from this tree will require a multi -pronged approach. • Traffic reduction: Reducing the amount of time spent by the public underneath this tree will greatly reduce the risk of damage and or injury. o Making this street one way o Creating a no parking zone under the tree o Removing the sidewalk and installing anew sidewalk in the west side of the road. • Pruning: Older trees require a delicate touch when it comes to pruning. Too much pruning will hurt the tree and, in this case, not enough pruning will not provide the desired results. Therefore, I am proposing to do the pruning in two stages as a significant amount of live branches will need to be removed to reduce the risk on this tree. Year 1 o Removal of all deadwood 2 cm and larger in the crown of the tree; o The long limb over the road should be cut back to reduce the weight and the length of it. Reduction cuts for this limb shall be no larger the 25 cm. o The accompanying photographs indicate the propose location of the reduction cuts. • The limb growing to the south over the lawn shall be thinned and only reduced slightly. Reduction cuts for this limb shall be no larger than 5 cm. Year 2-3 Evaluation of the tree to monitor for any decline; o Based on evaluation suggest further reduction pruning: • The limb to the south shall be reduced further. Reduction cuts for this limb shall be no larger the 25 cm Year 4-6 o Monitor tree for decline and visually inspect cabling system Year 7 o Removal of deadwood and pruning to further reduce the weight of limbs throughout the tree. Removal of life material shall be no more than 15%. Continued pruning once every 5-7 years as needed to remove deadwood and reduce weight. Cabling: The long limbs in this tree can be supported with a cabling system. This will be in addition to the limb reduction. The cables are there to help support the limbs but also in case of a limb failure the cables are more likely to keep the limbs from falling to the ground. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Specifications Pruning: This document is to be used as a specification for the pruning of the red oak located in the front yard of 21 Beech Ave, Bowmanville. The work is to be carried out in accordance with the specifications set out her in which follow the ANSI A00 standard This work is to be carried out by ISA certified arborists. Objective: This veteran tree has some very long limbs that will need to be reduced. No more than 15% of live tissue can be removed at any one time over a period of 2 years. Branches: Year 1 Removal of all deadwood 2 cm and larger in the crown of the tree; The long limb over the road should be cut back to reduce the weight and the length of it. Reduction cuts for this limb shall be no larger the 25 cm. o The accompanying photograph indicate the proposed location of the reduction cuts. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 • The limb growing to the south overt he lawn shall be thinned and only reduced slightly. RUURD VAN DE VEN, ISA BCMA 2 Van de Ven Consulting Group 905-955-4856 Year 4-6 o Monitor tree for decline Year 7 Removal of deadwood and pruning to further reduce the weight of limbs throughout the tree. Removal of life material shall be no more than 15%. RUURD VAN DE VEN, ISA BCMA Van de Ven Consulting Group 905-955-4856 Cabling: This document is to be used as a specification for the cabling of the red oak located in the front yard of 21 Beech Ave, Bowmanville. The work is to be carried out in accordance with the specifications set out her in which follow the ANSI A00 standard This work is to be carried out by ISA certified arborists. The cabling system will require annual inspection, This is a visual inspection from the ground. Once every 5-7 years when the tree is pruned the system will need a closer inspection. Objectives: This tree has some very long limbs that will benefit from the installation of a cabling system. System: o The systems shall be installed to the ANSI A300 Standard (Part 3) supplemental support systems. o The system shall employ through bolts and Amon eye nuts or eyebolts 5/8" in diameter o The system shall employ Extra high strength cable 7/16" in diameter of Aircraft cable''/:" in diameter. o The system, shall be installed in the approximate location as indicated in the photograph. This location shall be confined on site in consultation with the consultant RUURD VAN DE VEN, ISA BCMA 11 z 3 (h 0 0 0 0 0 N O 0 0 0 p p p t O N 9 A v oE �w Z Q ` u N Q < .0 c 0 O OQ �•N d •a N _Z °> y 0 d c m U Z Z o >.E :00 L c ❑� ^-''c "� omc�U m�>� rn w m a_Evl �w �a c y y•d �LL � d�iv aQ p0'C Nr d UNm NU N QQ Q\yc= �'am � ' `�0° t= Q 0 3 m O 0 V O M C N N \ _ L N L Z�0a0=mma-OiCm v m^•ma? 0-a0i-6 c H H Q Q N m U U U 2 H U O Y i rm N c U m 0 w 0 N 0 V -� O. _O G-O m 5 O yY W N N Y .tea �LLMo CO. U N U l0 c 0 E 0 0E L a03 « -0m20 o U J E U)me OEmc 0 E w EL M a 0 V LLci O M T L« O o O> C OM. E 0 L0 3 N C a U O �v rn 0-y cc m U U 0m �00 O O.� c 0 O.O N CL L N CL C � �p N � O, O C u0i - O C O O 'O N O y C M E O J N_ fpN 4- o c N 0 0 C L O E O L E N c O L rn^ N L C E n•- T m •- 2�'cE U C 'o N o. c W O N 'O w O- m M = E N .0 ❑ _ U- r C O Q M W N J m f0 �i o 10 0 n W N w E p Q® LL m Mc MaO T cl m. >"O mad �a w � �m zp O J' rCM � Q m y N o E Z a 0 J z y 0 c 0 > > ~ N N C c 0 U U N> m O 0_ 0 O> O N Cl QD Jd �T aa«O.Oa o Q� �QJ V)<w«m aa�dc- QoE U EL pq 30=8m8 O Attachment 4 to Report PWD-030-21 m U N COPYRIGHT © IVAN B. WALLACE O.L.S. LTD. 2021 SKETCH TO ILLUSTRATE 21 BEECH AVENUE TOWN OF BOWMANVILLE SCALE 1 250 METRES 0 1 2 3 4 5 10 20 CAUTION THIS IS NOT A PLAN OF SURVEY AND SHALL NOT BE USED EXCEPT FOR THE PURPOSE INDICATED IN THE TITLE BLOCK. THE WORK AND DRAWINGS HEREIN WERE COMPLETED FOR THE EXCLUSIVE USE OF OUR CLIENT AND NO LIABILITY IS ASSUMED TO ANY THIRD PARTIES OR SUBSEQUENT OWNERS. GEOGRAPHIC LOCATION NOTE TOWN LOT 4 AND PART OF TOWN LOT 5, BLOCK 35, REGIASTERED PLAN H-50079, MUNICIPALITY OF CLARINGTON DISTANCE NOTES - METRIC DISTANCES ARE IN METRES AND CAN BE CONVERTED TO FEET BY DIVIDING BY 0.3048. S U R V E Y O R S IBWSURVEYORS.COM 1 1.800.667.0696