Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
Item 4b. Review a tree removal application to remove three (3) lemon-scented gum trees at 327 Los Cerros Dr. (Application No. TREE-0009-2026)
TREE COMMITTEE AGENDA REPORT SUBJECT: REQUEST FOR THE REMOVAL OF THREE (3) LEMON-SCENTED GUM TREES AT 327 LOS CERROS DR. (APPLICATION NO. TREE-0009-2026) FROM: Walter Gault, Urban Forestry Program Coordinator / City Arborist Phone Number: (805) 781-7578 Email: wgault@slocity.org RECOMMENDATION Review the proposed tree removal application for consistency with the Municipal Code Section 12.24.090(E) and provide a recommendation to the Community Development Director. Meeting Date: 5/18/2026 Item Number: 4b Time Estimate: 30 minutes Figure 1: Location of tree removal request (327 Los Cerros Dr.) Page 13 of 70 Item 4b TREE-0009-2026 Tree Committee Report – 5-18-2026 1.0 APPLICATION DESCRIPTION Steven Chen, the property owner and applicant, has requested the removal of three (3) Eucalyptus citriodora (lemon-scented gum) trees in the front yard at 327 Los Cerros Dr. located within the R-1 zone (Attachment A, Tree Removal Application Form). The property is also located within the “High” Fire Hazard Severity Zone. The applicant provided an assessment of the trees (Attachment B, Arborist Report) and has proposed to replace them with six (6) compensatory trees: three (3) dwarf olive trees, one (1) Harpephyllum afrum (African plum) and two (2) Prunus ilicifolia (holly-leaf cherry) (Attachment C, Replanting Plan). 2.0 COMMITTEE PURVIEW The Tree Committee’s role is to review the removal request in accordance with the process set forth in San Luis Obispo Municipal Code (SLOMC) Chapter 12.24, specifically Section 12.24.090(F)(2) - tree removals related to ministerial development permits on parcels other than R-1 or R-2. This code section utilizes the relevant additional application requirements in subsection (D)(2) and the criteria set forth in subsection (G). Figure 2: View of trees from Los Cerros Dr. Page 14 of 70 Item 4b TREE-0009-2026 Tree Committee Report – 5-18-2026 3.0 TREE REGULATIONS The City’s Tree Ordinance (Municipal Code Chapter 12.24) was adopted with the purpose of establishing a comprehensive program for installing, maintaining, and preserving trees within the City. This ordinance establishes policies, regulations, and specifications necessary to govern installation, maintenance, removal, and preservation of trees to beautify the city; to purify the air; to provide shade and wind protection; to add environmental and economic value; and to preserve trees with historic or unusual value. Criteria for Convenience Tree Removal Applications. SLOMC §12.24.090 subsection (F)(2) requires review by the Tree Committee using the criteria set for in SLOMC §12.24.090(G). Applicable criteria are provided in italics below and followed by a description of the proposed tree removals as it relates to that criterion. (G)(1). Size of Tree. The scale of the tree shall be considered, as well as the size of the tree’s canopy. Larger, more visually prominent trees may have a higher preservation priority than smaller, less visually prominent trees. The trees proposed for removal are large and visually prominent in the neighborhood. (G)(2). Location of Tree on Private Property. The location of the tree on private property shall be considered. Trees located in a private rear yard, which are not highly visible from the public right-of-way, may have a lower preservation priority than trees with a high visual impact to the neighborhood. The trees proposed for removal are highly visible from the public right-of-way and does have a high visual impact on the neighborhood. (G)(3). Species of Tree. Native trees shall have a higher preservation priority than non-native trees. The trees proposed for removal are non-native. (G)(4). Forestry Best Practice. The number of healthy trees that a given parcel of land will support shall be considered, and whether removal would enhance the health or survival of remaining trees. Applications tha t increase biodiversity of native trees and tree age distribution within a given area are preferred. The removal has little to no impact on remaining trees but the replanting plan would increase the tree-age diversity in the neighborhood. Page 15 of 70 Item 4b TREE-0009-2026 Tree Committee Report – 5-18-2026 (G)(6). Compliance with Subsection J of This Section Regarding Compensatory Plantings. The approving authority may consider an application proposal to provide compensatory plantings in excess of required minimums in evaluating this criterion. The applicant is proposing to exceed the minimum required replanting rate of 1:1 onsite with six (6) compensatory trees. (G)(7). Heritage Trees. Heritage trees have the highest preservation priority. The tree is not a heritage tree. 4.0 ACTIONS 4.1 Recommend findings of consistency with the Tree Regulations. An action recommending approval of the proposed tree removals based on consistency will be forwarded to the Community Development Director for final action. This action may include recommendations regarding the compensatory replanting plan with size and species of tree. 4.2 Recommend findings of inconsistency with the Tree Regulations. An action recommending denial of the proposed tree removals should include findings that cite the basis for denial and should reference inconsistency with the General Plan, Tree Regulations, or other policy documents. 4.3 Continue the project to a hearing date certain, or uncertain. An action continuing the review of the proposed tree removals should include direction to the applicant and staff on pertinent issues. 5.0 ATTACHMENTS A - Tree Removal Application Form B - Arborist Report C - Replanting Plan Page 16 of 70 City of San Luis Obispo, Community Development, 919 Palm Street, San Luis Obispo, CA, 93401-3218, 805.781.7170, slocity.org TREE REMOVAL APPLICATION For all Non-Construction and Construction related tree removals Owner Name: Applicant Name: Address: Address: City: Zip: City: Zip: Phone: Phone: Email: Email: Address of Tree(s): Number of trees applying to remove: Tree Species: Application Description & Reason for Removal: Is this removal a City Tree? YES NO DON’T KNOW Dog in yard? YES NO Is this associated with a Building Permit or Development Plan? _____ YES _____ NO If YES, please provide appropriate reference numbers: Is this property governed by a Homeowners Association (HOA)? YES NO If YES, please provide HOA Board Approved Meeting minutes authorizing tree removal(s) with your tree removal application. ALL ITEMS BELOW MUST BE INCLUDED TO PROCESS TREE REMOVAL APPLICATIONS Tree(s) banded with ribbon or duct tape for identification Site plan drawing or photo of tree site with Tree ID (Tree#1, Tree #2, etc.) Supporting documentation (repair, receipts, etc.) Photo log showing damage or reasons for removal1 Replanting plan2 Arborist Report3 INCOMPLETE APPLICATIONS WILL NOT BE ACCEPTED. FAILURE TO KEEP TREES BANDED MAY RESULT IN A REJECTED APPLICATION. 1.Include a photo log that clearly shows the trees requested for removal. All tree(s) must be uniquely identified by a number and a ribbon, or an identifier wrapped around the truck in the photo and prior to inspection. 2.Include a replanting plan in accordance with Section 12.24.090(J) of the City’s Municipal Code. A minimum 1:1 replanting rate is required for plantings onsite, and a minimum 2:1 replanting rate is required for plantings offsite or within the public right-of-way. 3.An application for tree removal on a site where a discretionary or ministerial development permit is requested shall include an arborist report and a site plan that includes accurate drip line delineation and cross sections of construction work impacting both trees proposed for removal and trees planned to remain. 4.If an "Imminent Hazard to Life or Property" Application is being submitted, a statement from a TRAQ Qualified & Certified Arborist must be provided.Page 17 of 70 Tree Removal Decisions as outlined in Section 12.24.090 of the City’s Municipal Code SELECT TYPE OF TREE REMOVAL APPLICATION BEING SUBMITTED DECISION MAKER Imminent Hazard to Life or Property SLOMC 12.24.090(E)(1)(a) City Arborist Tree Health and Hazard Mitigation SLOMC 12.24.090(E) City Arborist Convenience Removal SLOMC 12.24.090(E)(3) Tree Committee makes recommendation to Community Development Director Community Development Director Minor Ministerial Development Permit SLOMC 12.24.090(F)(1) Removal for residential or accessory construction on an R-1 or R-2 lot City Arborist Discretionary Permits Construction Tree Removal SLOMC 12.24.090(F)(3) Community Development Director Major Development / Tentative Tract Map/ Conditional Use Permit SLOMC 12.24.090(F)(4) Planning Commission Submittal Instructions Submit Tree Removal applications to the City of San Luis Obispo, Community Development Department at the following address: 919 Palm Street, San Luis Obispo, CA 93401 or by email to trees@slocity.org. Payment of the “Tree Removal Permit” fee shall be submitted along with this application. Refer to the City’s current Comprehensive Fee Schedule for the current fee. Property Owner Authorization: By signing this application, I certify that I have reviewed this completed application and the attached material and consent to its filing. I agree to allow the Community Development Department to duplicate and distribute submitted materials to interested persons as it determines is necessary for the processing of the application. Signed Date Applicant/ Representative Certification: By signing this application, I certify that the information provided is accurate. I understand the City might not approve what I’m applying for or might set conditions of approval. I agree to allow the Community Development Department to duplicate and distribute submitted materials to interested persons as it determines is necessary for processing of the application. Signed Date Permission to Access Property: This section is to be completed by the property owner and/or occupant who controls access to the property. To adequately evaluate the submitted proposal, Community Development Department Staff, Commissioners and City Council Members will have to gain access to the exterior of the real property in order to adequately review and report on the proposed request. Your signature below certifies that you agree to give the City permission to access the project site from 8 a.m. to 5 p.m., Monday through Friday, as part of the normal review of this application. Signed Date Indemnification Agreement: The Owner/Applicant shall defend, indemnify and hold harmless the City or its agents or officers and employees from any claim, action or proceeding against the City or its agents, officers or employees, to attack, set aside, void, or annul, in whole or in part, the City’s approval of this project. In the event that the City fails to promptly notify the Owner / Applicant of any such claim, action or proceeding, or that the City fails to cooperate fully in the defense of said claim, this condition shall thereafter be of no further force or effect. Signed Date Statement from Certified Arborist with TRAQ Page 18 of 70 Chaparral Environmental Consulting, LLC 21522 Carriso Rd Diamond Bar, CA 91765 chaparralenviro@gmail.com (909) 477-7344 ARBORIST REPORT Prepared for Steven Chen 1382 Oceanaire Blvd San Luis Obispo, CA 93405 stvnenator@gmail.com (650) 224-9375 Prepared by Daniel Seong Chaparral Environmental Consulting, LLC chaparralenviro@gmail.com (909) 477-7344 Location 327 Los Cerros Dr San Luis Obispo, CA 93405 Submitted on October 15, 2025 Tree Risk Assessment on Los Cerros Dr Page 19 of 70 Intentionally left blank Page 20 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 1 of 31 Table of Contents Summary .......................................................................................................................... 2 Introduction ...................................................................................................................... 3 Background ...................................................................................................................... 3 Scope of Work .................................................................................................................. 3 Purpose ........................................................................................................................... 4 Limitations of the Assignment .......................................................................................... 4 Assessment ...................................................................................................................... 5 Methodology .................................................................................................................... 5 Site Observations and Analysis ........................................................................................ 6 Tree Observations and Analysis ........................................................................................ 7 Discussion ..................................................................................................................... 10 Conclusion .................................................................................................................... 11 Risk Mitigation Options .................................................................................................. 12 Recommendations ......................................................................................................... 12 Supplemental Information ................................................................................................ 13 Tables ............................................................................................................................ 13 Photographs .................................................................................................................. 15 Glossary ........................................................................................................................ 28 Assumptions and Limiting Conditions................................................................................ 30 Certificate of Performance ............................................................................................... 31 Page 21 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 2 of 31 Summary On October 3, 2025, Mr. Chen requested a tree risk assessment for three Lemon-scented gums on his property. The assignment also called for collecting basic measurements from each tree and marking them with flagging tape. I conducted a Level 2 Assessment on October 4, 2025 and found some conditions of concern among the subject trees. The most notable one is a codominant stem on Tree 1 leaning towards the house. Within a two year time frame, Tree 1 was categorized as having an overall MODERATE risk, while Trees 2 and 3 were categorized as having an overall LOW risk. In addition, I recorded the basic measurements of each tree and wrapped their trunks with pink colored flagging tape. I recommend retaining and monitoring Tree 3 and scheduling a tree care company to prune Trees 1 and 2. Risk mitigation for Tree 1 will be costly and require a long-term commitment to maintenance, so removal of this tree is a feasible option depending on Mr. Chen’s budget and risk tolerance. For all subject trees, supplemental irrigation should be withheld, annual pruning should be scheduled to remove deadwood, and a re-inspection should be conducted in two years. Page 22 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 3 of 31 Introduction Background On October 3, 2025, Mr. Chen contacted me regarding three Lemon-scented gums trees (the subject trees) on his property. Mr. Chen expressed concerns about their structural integrity and wanted to evaluate the risks the trees pose to his house. As a result, my assignment was to conduct a tree risk assessment and provide a risk rating for each tree in this written report. In addition, he requested that I record the measurements of the subject trees and that they be flagged for visibility during my site visit. In a phone conversation, Mr. Chen provided information on the site’s history and use. He purchased this property in May 2025. At the moment, he does not reside at this property, nor does he have any tenants or occupants. Currently, landscapers come and maintain the property once a month in his absence. However, no one conducts any maintenance work on the subject trees themselves. The front yard has a drip irrigation system that is installed close to the trees, but Mr. Chen reports that it is inactive. He does not know how long the subject trees have been present, but has noticed branches drop from them. The backyard is undergoing renovation for new tile installation, with work ongoing until the installation is complete. Mr. Chen is not aware of any other recent construction on the property. The property falls within the jurisdiction of the City of San Luis Obispo. According to San Luis Obispo Municipal Code §12.24.090(C)(1), non-native trees measuring greater than 20 inches in diameter at breast height (dBH) are protected by municipal ordinance. As a result, all three subject trees are regulated by the City. Scope of Work My assignment was to: Provide a Level 2 Assessment on the subject trees located at 327 Los Cerros Dr. The site visit was scheduled for October 4, 2025. Collect basic measurements from each subject tree: dBH, height, and drip line radius. Provide a risk rating to the primary target of concern, the house on the property, from each subject tree based on my findings and analysis. Additional targets of concern were identified during the inspection and included in the assessment. Provide a residual risk rating from each subject tree. Provide observations of site conditions and existing problems, along with my analysis. Provide risk mitigation options and recommendations, based on the results of my assessment. Provide a written arborist report, due by October 19, 2025, that includes all of the information outlined in the scope of work. Mark the subject trees with flagging for visibility. Page 23 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 4 of 31 Purpose The purpose of this report is to assess the risk that the subject trees pose, provide mitigation options and recommendations, and document the assessment’s methodology, data, and results. This report is intended for Mr. Chen’s use to inform decision making while managing his property. If needed, Mr. Chen is free to share this report with a tree care company or submit it with a tree permit application to the City of San Luis Obispo. Limitations of the Assignment Trees 2 and 3 are located along the southern edge of the property, adjacent to the neighboring residence. A portion of those canopies could not be seen without entering the neighboring property. As a result, any defects which may be present and only observable from those angles were not identified. The tree(s) discussed within this report were inspected by visual observation, at grade, using simple handheld tools. No excavation, aerial inspection, internal sampling, or other specialized tools or methods were utilized during this assessment. As a result, any defects hidden below ground or inside the tree were not identified. Trees are living organisms that continuously grow, develop, and respond to external stimuli and environmental conditions. This report is based on conditions at the time of observation and does not provide any guarantee, expressed or implied, that problems or deficiencies will not occur in the future, from any cause. This assessment is limited in scope and does not include any and all risks. The given time frame in this assessment is a point of reference for the level(s) of risk determination. All trees could fail eventually, given a long enough time frame. It is not a considered a guarantee period. Any tree, whether it has visible weakness or not, will fail if the forces applied exceed the strength of the tree or its parts. Page 24 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 5 of 31 Assessment Methodology For each subject tree, I calculated the dBH by measuring the circumference of the trunk at 4.5 feet above grade with a measuring tape. Height measurements were recorded using a Nikon Forestry Pro II© rangefinder. To measure drip line radius, I measured the distance from the trunk to the edge of the canopy, in each cardinal direction. The averages of these four measurements resulted in the average drip line radius. The lean of each tree was visually estimated using a plumb bob. Inspection of the site, lower canopy, main stem and lower branches were conducted via direct visual observation. Using a rubber mallet, I sounded the buttress roots and trunks while listening for tonal changes to estimate the extent of any internal decay. Visual inspection of the upper canopy was conducted using a pair of binoculars. A smart phone was used to take 100 digital photographs of the subject trees and associated site. Of those, 12 were attached in this report. All photographs were time stamped, dated, and marked with GPS coordinates in decimal degree format. In addition, historic street view imagery on Google Maps was viewed to observe site conditions during previous years. I was provided with information on the site’s use and history in a phone conversation with the property owner, Mr. Chen. The Tree Risk Assessment Process I evaluated the subject trees with a Level 2 Assessment, following the methods outlined in the ISA Tree Risk Assessment Manual and ANSI A300 Tree Care Standards. Each tree was inspected to identify conditions of concern that pose a risk to a specified target within a defined time frame. In this assessment, I evaluated three targets using a time frame of two years. Conditions of concern were categorized in each of the following three components: (1) Likelihood of failure, (2) Likelihood of impact, and (3) Consequences of failure. The categories are defined as: Likelihood of failure: 1. Improbable – Failure is not likely to occur within the time frame during normal weather conditions, and may not fail in extreme weather conditions. 2. Possible – Failure may be expected within the time frame in extreme weather conditions, but is unlikely during normal weather conditions. 3. Probable – Failure may be expected within the time frame under normal weather conditions. 4. Imminent – Failure has started or is most likely to occur in the near future, even if there is no significant wind or increased load. The imminent category overrides the stated time frame. Likelihood of Impact: 1. Very low – The chance of the failed tree or tree part impacting the specified target is remote. 2. Low – There is a slight chance that the failed tree or tree part will impact the target. 3. Medium – The failed tree or tree part could impact the target, but is not expected to do so. 4. High – The failed tree or tree part is likely to impact the target. Page 25 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 6 of 31 Consequences of failure: 1. Negligible – No personal injury, low-value property damage, or disruptions that can be replaced or repaired. 2. Minor – Minor personal injury, low-to-moderate value property damage, or small disruptions of activities. 3. Significant – Substantial personal injury, moderate-to-high-value property damage, or considerable disruption of activities. 4. Severe – Serious personal injury or death, high-value property damage, or major disruption of important activities. Based on these categories, I determined the likelihood of failure and impact and risk rating of each condition by using the matrices in Figures 3 and 4. Each tree’s overall risk rating was based on its highest rated condition of concern. Site Observations and Analysis The Property on Los Cerros Dr The property consists of a single family residence and its surrounding landscape, situated at the edge of urban development on the southeastern slopes of Bishop Peak. This results in the site being fully exposed to prevailing winds from the northwest. The lot is gently sloped downhill to the east, with the house standing as the only notable structure on site. Hardscape features on site include a driveway, walkway, retaining walls along the property boundaries, and a planter in the front yard. The landscaping is well-maintained and includes several shrubs and small trees, in addition to the three subject Lemon-scented gums standing dominant in the neighborhood. An irrigation system is installed throughout the front yard. However, the system is currently inactive, according to Mr. Chen. It is unclear how long it has been in this state, though this works out in favor of the subject trees as regular watering is not recommended for them anyway. A stump from a recently removed tree was observed near the northern property boundary. Along the same boundary, a drainage feature was observed, modified to flow through a culvert beneath Los Cerros Dr. Along with the site’s topography, this feature provides favorable conditions for regulating soil moisture. In the backyard, active renovation of the tiling was observed, although the workers were not on site at the time of the assessment. The Target(s) Based on Mr. Chen’s description of the site and observations made during the site visit, I considered three targets that could be impacted by failure of the subject trees or tree parts: 1. The house – This target was considered to have a constant occupancy rate, since it is a fixed structure and relocating the target is not feasible. 2. Workers on the property – Workers were defined as landscapers, tile setters, and other individuals performing maintenance or renovation on the property. They were considered to have an occasional occupancy rate, given the ongoing backyard renovation and monthly landscape maintenance. Workers are assumed to be present only during normal business Page 26 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 7 of 31 hours and oƯ site during severe weather events. They are also considered mobile targets, as they are likely to be in motion throughout the day rather than remain stationary, primarily using established paved walkways to navigate the property. 3. Vehicles – Vehicles belonging to the workers were considered to have an occasional occupancy rate, since they would only be present along with the workers. Vehicles were considered to most likely to be parked in the driveway. They were considered to be movable targets, since parking on the driveway can be restricted and alternative parking spaces on the street are available. Tree Observations and Analysis Trees 1-3 While Mr. Chen is unaware of the exact ages of the subject trees, historic street view imagery reveals that they have been on site since at least December 2007 (Figure 6). Based on the current size of the trees, their size in 2007, and the expected growth rate of this species, I estimated them to be at least 25 years old. All three trees were confirmed to be Lemon-scented gums (Corymbia citriodora). The foliage of the trees are healthy and green, and the root flare of each tree is suƯiciently exposed with no signs or symptoms of basal decay. Sounding each tree with a rubber mallet yielded no tonal changes, indicating no internal decay being present. Overall, the subject trees are well established, adapted to site conditions and exhibit good vitality, which facilitates further adaptation to wind loading and other mechanical stressors. Tree 1 Tree 1 is located in front of the porch, near the northeast corner of the property. The tree has a dBH of 28.3 inches and a height of 71 feet. The drip line extends 2 feet to the north, 24 feet to the east, 33 feet to the south, and 20 feet to the west, resulting in an average drip line radius of 19.8 feet. The canopy is estimated to have a live crown ratio (LCR) of 40%. The tree has a codominant stem configuration with a narrowly angled, V-shaped branch union originating 3 feet above grade. Included bark is present below the union, reducing attachment strength between the two stems. Response growth is present below the union and between the stems, and a clockwise twist can be seen along both codominant stems (Figure 10). The entire tree has a bowed lean of approximately 30 degrees toward the south, aimed at the front of the house and entry steps (Figures 8, 12). A 10 inch diameter limb extends from one of the codominant stems and overhangs the house approx. 40 feet above the roof (Figure 9). A stump from a recently removed tree of the same species is present approximately 5 feet to the northwest (Figure 11). Historic street view imagery shows this removal occurred between June 2023 and September 2025 (Figure 6). The loss of this neighboring tree has exposed Tree 1 to winds from the northwest and likely increased wind loading. Meanwhile, drip line measurements show that the crown is unbalanced and favors growth toward the southeast. Most likely, the unbalanced crown and bowed lean developed as the tree grew toward available light while competing with its former neighbor. Trees that mature under protected conditions often lack the structural adaptations Page 27 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 8 of 31 needed to withstand direct wind exposure, and Tree 1’s architecture amplifies the forces acting on its codominant union during strong winds. Despite this, Tree 1 shows signs of adaptation. The visible trunk twist indicates the formation of reaction wood in response to mechanical and torsional stress, The presence of response growth below the codominant union also suggests the tree is actively reinforcing this structural defect. Based on these factors, the likelihood of failure of the codominant stem is considered to be possible. In the event of failure, the likelihood of impact to the house is high because the tree leans directly toward the front of the house without any protection factors. The likelihood of impact to workers is very low, since they would most likely be elsewhere on the property and have little reason to be on the front steps leading to the front door of an unoccupied house. Workers are also mobile targets, reducing the likelihood of being present in the target zone at the time of failure. Additionally, the codominant stem would strike the roof first, providing a degree of protection. Lastly, workers are unlikely to be present during storms when failure is most likely. The consequence of failure from striking the house would be significant, as the size and height of the tree part could cause substantial structural damage requiring costly repairs. The consequence of failure from impacting a worker would be severe, as impact from a tree part of this size could easily result in fatal or life-altering injury. The 10 inch diameter limb also has a possible likelihood of failure due to the concentration of foliage at branch tips and exposure to prevailing winds. In the event of failure, the likelihood of impact to the house is high, while the likelihood of impact to workers remains very low. The consequence of failure to the house would be minor, as the smaller limb size would cause superficial damage to the shingles. The consequence of failure from striking a worker would remain severe. Although the roof would likely catch the foliage and reduce the limb’s velocity, a tree part of this size falling from a height of 40 feet will still generate enough force to cause fatal or life-altering injuries. Tree 2 Of the two trees lining the driveway, Tree 2 is positioned closest to the curb, along the southeastern boundary of the property. It measures 24.4 inches dBH and 67 feet in height. The drip line extends 16 feet to the north, 19 feet to the east, 26 feet to the south, and 14 feet to the west, resulting in an average drip line radius of 18.5 feet. The canopy exhibits an estimated 15% LCR with little to no interior branching. Overall, Tree 2 is sheltered from wind exposure from the northwest by Tree 1 and from the west by Tree 3. The trunk is straight and upright with no visible lean. Along with the branches, the growth habit resembles normal phototropic orientation. The drip line measurements reveal a slight canopy growth bias toward the south but also show restriction on the western side. This pattern is likely the result of competition with Tree 3’s canopy rather than wind loading. The tree grows in a narrow soil strip between Mr. Chen’s and the neighbor’s driveways, with about 30% of its drip line area covered by pavement. Historic street view imagery shows that construction on the neighboring property, located roughly 5 feet south of the tree, occurred between December 2007 and February 2012. Based on the tree’s healthy canopy, response growth, and the time elapsed since construction, it appears to have successfully adapted to these disturbances. Page 28 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 9 of 31 Extensive shear plane cracking was observed along the trunk and limbs, but these cracks show evidence of response growth formation (Figure 14). In addition, they are shallow in depth and do not appear to extend into the sapwood of the tree. These cracks are likely a result of bark expansion and signal that the tree is growing rapidly. Bark shedding is normal and expected for this species and is not considered an indicator of decay or decline. At the base of a former branch union approx. 40 feet high on the northern aspect of the tree, a torn branch stub was observed with the opposing branch still attached. The wound was visibly decayed, and acorn woodpeckers (Melanerpes formicivorus) were observed feeding on insects at the site of the wound (Figure 15). The aƯected tree part, the branch remaining on the union, was estimated to be 6 inches in diameter and is positioned directly above the driveway (Figure 16). The likelihood of failure of the 6 inch diameter branch is considered probable, due to evidence of prior branch failure and visible decay at the branch union. The likelihood of impact to workers is very low, as they are unlikely to be present in the driveway during working hours or storms. The likelihood of impact to vehicles is low, since vehicles are most likely to be parked on the driveway while the workers are elsewhere on site. The consequences of failure would be significant for workers and minor for vehicles, as a branch of this size falling from 40 feet would break a windshield, deform the body of a vehicle, or cause substantial injury to a person. There are no protection factors within the target zone. Tree 3 Tree 3 is located adjacent to the driveway, immediately west of Tree 2, and is planted within the same narrow strip of soil situated between the two property’s driveways. The tree has a dBH of 24.8 inches and a height of 63 feet. The drip line extends 21 feet to the north, 8 feet to the east, 22 feet to the south, and 25 feet to the west, resulting in an average drip line radius of 19 feet. Approximately 30% of the area within the drip line is covered by pavement. Construction of the neighboring property occurred approximately 5 feet south of this tree, sometime between December 2007 and February 2012. It is likely that Tree 3 has also adapted to the nearby construction that occurred between December 2007 and February 2012. The LCR is estimated to be at 40%. Based on drip line measurements, Tree 3’s crown is reduced in size on the eastern side, likely due to shading and competition for light. Continuing the similarities with its neighboring tree, Tree 2 showed a similar reduction on its western aspect, which further suggests mutual canopy competition rather than wind eƯects. This tree is also protected from wind exposure by Tree 1 to the north. Therefore, the canopy shape of Tree 3 is unlikely to have been significantly influenced by wind exposure. The tree exhibits a multi-trunk configuration with four main leaders originating from a single point of attachment (Figure 18). All leaders display an upright, sweeping growth pattern consistent with normal phototropic response, an indicator of good overall health and vitality. Large pruning wounds, likely from previously removed competing leaders, are visible on the neighbor’s side and fully compartmentalized (Figure 19). The leaders are positioned directly adjacent to the driveway, originating at a height of 5 feet above grade. Of these, the 12 inch diameter leader closest to the house was identified as a condition of concern (Figure 17). Multi-trunk configurations originating from a common attachment point are considered structural defects and are generally associated Page 29 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 10 of 31 with an increased likelihood of failure under load. Although removing large diameter leaders on the neighbor’s side would have initially altered the tree’s load distribution, the advanced compartmentalization of the pruning wounds indicates a substantial amount of time has passed since then, and the tree has likely adapted to the new balance. Based on this information, the likelihood of failure of the 12 inch diameter leader is considered possible. The likelihood of impact to the house is high, as the branch is oriented toward the structure. The likelihood of impact is very low for workers and low for vehicles. The consequence of failure from impacting the house would be negligible, as the structure is positioned far enough away that only the branch tips would make contact rather than the main stem. However, the consequence of failure from impacting vehicles would be significant, and severe for workers, as they could be struck by the full length of the falling stem, resulting in crushed vehicles or potentially fatal injuries. No protection factors are present within the target zone. Discussion All subject trees exhibit a low LCR with minimal to no interior branching resulting in tree architecture that resembles lion tailing, an unacceptable pruning practice that result in a concentration of foliage at the branch tips. Furthermore, a lack of interior branching results in a reduction of mass damping during high winds, resulting in more force being transferred to the trunk and roots. These characteristics are typical for Lemon-scented gums, a species widely cultivated in southern California for its drought tolerance and adaptability to well-drained soils. This species performs best under full sunlight and does not tolerate shade, resulting in open canopies with little to no interior foliage. Most conditions of concerns were found in the canopy in the form of branches. Appropriately, this species is known to drop seemingly healthy branches without warning in a phenomenon known as Sudden Branch Drop (SBD). This is most commonly observed in the summer, during extended periods of high temperatures. Currently, SBD is not fully understood within the field of arboriculture. In contrast, the trees are in good health and showing strong adaptation responses with no indicators of root failure or instability. The main condition of concern is the codominant stem present on Tree 1, which presents the highest overall risk on the property. Risk management of this tree leaves limited mitigation options which will require long-term commitment to maintenance, and have a higher potential to be detrimental to the tree’s long term health. While pruning is typically appropriate to reduce wind loading on a tree, excessive pruning will lead to a severe reduction in photosynthetic capacity and development of water sprouts, aƯecting long term stability. Because this tree already has a small canopy with limited foliage volume, pruning to mitigate risk must be done gradually over the course of several growing seasons. Further discussing the codominant stem on Tree 1, supplemental support systems would not be feasible in this scenario, as their eƯectiveness would be limited and they may interfere with the tree’s development of response growth. A dynamic rope system’s benefits come from allowing controlled movement which enables continued development of response growth. However, these systems are most eƯective when codominant stems move in opposite directions, allowing the rope Page 30 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 11 of 31 to counteract those forces. Because both codominant stems lean in the same direction, this system would remain slack for most of the time if installed. A static cable system would restrict the natural movement needed for response growth formation and can alter load distribution by shifting stress towards the trunk and root system. Brace rods installed through both codominant stems would reduce torsional stress but would not improve resistance to forward bending. In addition, they would limit movement and inhibit further response growth, similar to static cabling. Lastly, supplemental support systems have the potential to do further harm if not installed properly and maintained. Conclusion In my opinion, the risk ratings for each subject tree are as follows, based on a two year time frame: Tree 1 is categorized as an overall MODERATE risk rating: o The likelihood of the codominant stem leaning towards the house failing and striking the house, causing significant damage, poses a MODERATE risk o The likelihood of the codominant stem leaning towards the house failing and striking a worker, causing severe damage, poses a LOW risk o The likelihood of the 10 inch diameter branch overhanging the roof failing and striking the house, causing minor damage, poses a LOW risk o The likelihood of the 10 inch diameter branch overhanging the roof failing and striking a worker, causing severe damage, poses a LOW risk Tree 2 is categorized as an overall LOW risk rating: o The likelihood of the 6 inch diameter branch above the driveway failing and striking a worker, causing significant damage, poses a LOW risk o The likelihood of the 6 inch diameter branch above the driveway failing and striking a parked vehicle, causing minor damage, poses a LOW risk Tree 3 is categorized as an overall LOW risk rating: o The likelihood of the 12 inch diameter stem failing and striking the house, causing negligible damage, poses a LOW risk o The likelihood of the 12 inch diameter stem failing and striking a worker, causing severe damage, poses a LOW risk o The likelihood of the 12 inch diameter stem failing and striking a parked vehicle, causing significant damage, poses a LOW risk The measurements for dBH, height, and drip line radius of each tree are recorded in Figures 1 and 2, on page 13. Page 31 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 12 of 31 Risk Mitigation Options Based on these results, I present the following risk mitigation options, along with the residual risk if you choose that action: 1. Retain and monitor the subject tree(s). This will maintain the current risk rating. Reassess the need for further action if you observe any new conditions of concern, especially after storms. If you decide to alter the property’s use by moving into the house or renting it out, an additional assessment is recommended. 2. Remove the subject tree(s). This will eliminate the risk associated with the tree(s). However, it would also eliminate the benefits provided by the tree(s). All subject trees are protected by municipal ordinance in San Luis Obispo due to measuring over 20 inches dBH, and will require a tree permit to legally remove. 3. Perform structural pruning on Tree 1. The pruning objective should be risk mitigation of the codominant stem and the 10 inch diameter limb over the roof, using a natural pruning system. Pruning should be selective and focus on small-diameter removals and overextended branches, removing no more than 15% of the canopy during each pruning cycle. This mitigation option may take several years of maintenance to reduce the residual risk to LOW. 4. Perform structural pruning on Tree 2. The pruning objective should be subordination and eventual removal of the branch with open decay, using a natural pruning system. Pruning should removing no more than 15% of the canopy during each pruning cycle. The residual risk from the tree part will be eliminated from the tree. The overall risk rating of Tree 2 will remain at LOW, since it is not possible to lower the risk rating any further without removing the tree. For all mitigation options involving pruning or support system installation, hire a tree care company with an ISA Certified Arborist available on staƯ and ensure that their work adheres to ANSI A300 tree care standards. Ideally, pruning should be scheduled in late spring or early summer. Recommendations In addition, I recommend taking the following actions: 1. Re-inspect the subject trees in two years. The inspection should be carried out by a Tree Risk Assessment Qualified arborist. If you prefer to have a second opinion, you can look up local arborists in your area using the “Find an Arborist” tool on www.treesaregood.org. Consider re- assessment as soon as possible if the property’s use changes (you decide to move in, or rent out the house) 2. (Continue to) withhold supplemental irrigation. If you wish to activate the irrigation line that is currently installed, consider redirecting it to avoid overwatering the subject trees. Lemon- scented gums are drought adapted and do not tolerate excessive moisture in the soil. 3. Schedule routine maintenance. Every year, hire a tree care company to remove dead branches from the subject trees. The pruning objective should be to remove deadwood and improve structure, using a natural pruning system. Ideally, pruning should be scheduled in late spring to early summer. Ensure that the tree care company has an ISA Certified Arborist available on staƯ and that their work adheres to ANSI A300 tree care standards. Page 32 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 13 of 31 Supplemental Information Tables ID Common name Scientific name dBH (inches) Height (feet) Average drip line radius (feet) Tree 1 Lemon-scented gum Corymbia citriodora 28.3 71 19.8 Tree 2 Lemon-scented gum Corymbia citriodora 24.4 67 18.5 Tree 3 Lemon-scented gum Corymbia citriodora 24.8 63 19 Figure 1. Species and measurements of each subject tree ID Drip Line Radius (feet) North East South West Average Tree 1 2 24 33 20 19.8 Tree 2 16 19 26 14 18.5 Tree 3 21 8 22 25 19 Figure 2. Drip line radius of each subject tree, from each cardinal direction Likelihood of Failure Likelihood of Impact Very low Low Medium High Imminent Unlikely Somewhat likely Likely Very likely Probable Unlikely Unlikely Somewhat likely Likely Possible Unlikely Unlikely Unlikely Somewhat likely Improbable Unlikely Unlikely Unlikely Unlikely Figure 3. The likelihood matrix used to estimate the likelihood of a tree or tree part failure impacting a specified target Likelihood of Failure & Impact Consequence of Failure Negligible Minor Significant Severe Very likely Low Moderate High Extreme Likely Low Moderate High High Somewhat likely Low Low Moderate Moderate Unlikely Low Low Low Low Figure 4. The risk rating matrix showing the level of risk as the combination of likelihood of a tree or tree part failing and impacting a specified target, and the severity of the associated consequences. Page 33 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 14 of 31 Ov e r a l l R i s k Ra t i n g MO D E R A T E LO W LO W Ri s k R a t i n g MO D E R A T E LO W LO W LO W LO W LO W LO W LO W LO W Co n s e q u e n c e s o f F a i l u r e Si g n i f i c a n t Se v e r e Mi n o r Se v e r e Si g n i f i c a n t Mi n o r Ne g l i g i b l e Se v e r e Si g n i f i c a n t Li k e l i h o o d o f Fa i l u r e & I m p a c t So m e w h a t L i k e l y Un l i k e l y So m e w h a t L i k e l y Un l i k e l y Un l i k e l y Un l i k e l y So m e w h a t L i k e l y Un l i k e l y Un l i k e l y Li k e l i h o o d of I m p a c t Hi g h Ve r y L o w Hi g h Ve r y L o w Ve r y L o w Lo w Hi g h Ve r y L o w Lo w Ta r g e t Ho u s e Wo r k e r s Ho u s e Wo r k e r s Wo r k e r s Ve h i c l e s Ho u s e Wo r k e r s Ve h i c l e s Li k e l i h o o d of F a i l u r e Po s s i b l e Po s s i b l e Pr o b a b l e Po s s i b l e Co n d i t i o n o f Co n c e r n Co d o m i n a n t st e m 10 i n c h di a m e t e r br a n c h o v e r th e f r o n t 6 i n c h di a m e t e r br a n c h o v e r th e d r i v e w a y 12 i n c h di a m e t e r le a d e r o v e r th e d r i v e w a y Tr e e 1 2 3 Figure 5. Table summarizing all components utilized in following the tree risk assessment process. Page 34 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 15 of 31 Photographs Figure 6. Historic street view imagery of the subject trees, taken from Los Cerros Dr. Pictures are arranged in chronological order, starting from the top left, rotating clockwise – from December 2007 to September 2025. The photo at the bottom left dated October 2025 was taken on site by the arborist during the assessment. The removal of a Lemon-scented gum next to Tree 1 is noticeable between June 2023 and September 2025. Construction of the neighboring property occurred between December 2007 and February 2012. Figure 7. Aerial overview of the site, viewed on Google Maps. The subject tree locations and drip lines are depicted as a rough sketch. Page 35 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 16 of 31 Figure 8. The degree of lean on Tree 1, visually estimated to be at 30 degrees to the south, using a plumb bob. Page 36 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 17 of 31 Figure 9. The 10 inch diameter limb on Tree 1, positioned approximately 40 feet over the roof of the house. This tree part was given a risk rating of LOW. Page 37 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 18 of 31 Figure 10. Narrow angled, V-shaped codominant stem with included bark, located approximately 3 feet above grade on Tree 1. Response growth is visible beneath the union. No cracks or other indicators of internal decay were detected. This tree part was given a risk rating of MODERATE. Page 38 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 19 of 31 Figure 11. The stump of a recently removed Lemon-scented gum, located approx. 5 feet northwest of Tree 1. This tree was removed some time between June 2023 and September 2025, exposing Tree 1 to additional wind loading. In the background, Tree 3 is visible in the upper right corner. Page 39 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 20 of 31 Figure 12. View of the codominant stem of Tree 1 leaning to the south, towards the front of the house. A clockwise twist can be seen in the trunk, indicating torsional stress. Page 40 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 21 of 31 Figure 13. A representative photo of Tree 2, which is located between Mr. Chen’s and the neighbor’s property, in a narrow strip of soil between the two driveways. Tree 3 is also depicted behind and to the right of Tree 2. Page 41 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 22 of 31 Figure 14. Shear plane cracks resulting from rapid wood growth are visible throughout the trunk and branches of Tree 2, along with visible response growth. Page 42 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 23 of 31 Figure 15. An acorn woodpecker (Melanerpes formicivorus) on Tree 2, foraging for insects within a decayed wound near the base of an 8 inch limb extending over the driveway. The wound is visibly decayed, and the presence of insects within the wound further confirms its condition. Page 43 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 24 of 31 Figure 16. The 8 inch limb on Tree 2 with visible decay at the base (circled in red), hanging over the driveway at a height of 40 feet. The canopy of Tree 1 is visible on the right. This tree part was given a risk rating of LOW. Page 44 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 25 of 31 Figure 17. Overview of Tree 3. The 12 inch diameter leader, closest to the house, was considered a condition of concern. This tree part was given a risk rating of LOW. The driveway and house were considered to be the target zone. Page 45 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 26 of 31 Figure 18. Multi-stem configuration on Tree 3. Multiple stems arising from the same point of attachment are considered a structural defect. The property in the background belongs to the neighbor. Page 46 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 27 of 31 Figure 19. Large diameter pruning wounds on the trunk of Tree 3. The pruning wounds are fully compartmentalized and originate from the same point of attachment as the other competing leaders on the tree. The pavement in the background is the driveway of Mr. Chen’s property. Page 47 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 28 of 31 Glossary Buttress root – Roots at the trunk base that help support the tree and equalize mechanical stress. Codominant stem – Forked branches nearly the same size in diameter, arising from a common junction and lacking a normal branch union. Compartmentalization – Natural defense process in trees by which chemical and physical boundaries are created that act to limit the spread of disease and decay organisms. Also known as CODIT (Compartmentalization of Decay In Trees). Diameter at breast height – Measurement of the trunk diameter, commonly measured at 4.5 feet above ground. Drip line – The soil surface area delineated by the branch spread of a single plant or group of plants. Grade (soil) – Surface level of the ground Included bark – Bark that becomes embedded in a crotch (union) between branch and trunk or between codominant stems. Causes a weak structure. Leader – Primary terminal shoot or trunk of a tree. Large, usually upright stem. A stem that dominates a portion of the crown by suppressing lateral branches. Lion tailing – The use of branch removal cuts to remove interior lateral branches, resulting in a concentration of growth at branch ends. Live crown ratio – The ratio of canopy length to total tree height. Mass damping – a process by which the amplitude of oscillations is reduced; in trees, motion created by the forces of wind or rigging operations may be reduced through branch movement. Mitigation options – Alternatives for reducing risk. Occupancy rate – The amount of time targets are within a target zone. Phototropism – Influence of light on the direction of plant growth. Tendency of plants to grow towards light. Pruning system – Process used to achieve the desired long-term form of the plant. Reaction wood – Wood formed in leaning or crooked stems, or on upper or lower sides of branches, as a means of counteracting the eƯects of gravity. Residual risk – Risk remaining after mitigation. Response growth – Wood growth that may increase the strength or stability of a tree in response to a defect or condition. Risk rating – The level of risk combining the likelihood of a tree failing and impacting a specified target, and severity of the associated consequences. Page 48 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 29 of 31 Root flare – Area at the base of the plant’s stem or trunk where the stem or trunk transition to roots. Sapwood – Outer wood (xylem) that is active in longitudinal transport of water and minerals. Shear plane crack – A crack at the neutral plane between tension and compression stresses. Structural pruning – pruning to influence the orientation, spacing, growth rate, strength of attachment, and ultimate size of branches and stems. Supplemental support system – A system designed to provide additional support or limit movement of a tree or tree part. Target – People, property, or activities that could be injured, damaged, or disrupted by a tree failure. Time frame – Time period for which an assessment is defined. Tree architecture – The structural form and shape of a tree. Tree risk assessment – A systematic process used to identify, analyze, and evaluate tree risk. Vitality – A plant’s ability to deal eƯectively with stress and thrive in a given environment. Wind loading – the force on a tree or structure resulting from the impact of wind. Page 49 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 30 of 31 Assumptions and Limiting Conditions 1. Unless expressed otherwise, information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the plant or property in question may not arise in the future, from any cause. 2. Not all conditions and defects are detectable. Trees may fail in ways that are not predictable, detectable ahead of time, or fully understood. Arborists cannot guarantee that a tree will be healthy or safe under all circumstances, or for a specified period of time. 3. All trees present some degree of risk that can be managed, but not eliminated. It is impossible to maintain trees free of risk. To live near trees is to accept some degree of risk. The only way to eliminate risk associated with trees, is to eliminate all trees. 4. All legal information provided to the arborist is assumed to be correct. No responsibility is assumed for matters legal in character. 5. The consulting arborist shall not be required to give testimony or attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services. 6. Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of the consulting arborist. 7. Alteration or loss of any part of this report invalidates the entire report. 8. Treatment, pruning, and/or removal of trees may involve considerations beyond the scope of the consulting arborist’s services such as property boundaries, property ownership, civil disputes, and other issues. Arborists cannot take such considerations into account unless complete and accurate information is disclosed to the arborist. An arborist should then be expected to reasonably rely upon the completeness and accuracy of the information provided. 9. The client may choose to accept or disregard any recommendations provided by this report, or seek additional consultation from an additional party. Page 50 of 70 Chaparral Environmental Consulting, LLC Tree Risk Assessment on Los Cerros Dr October 15, 2025 Page 31 of 31 Certificate of Performance I, Daniel Seong, certify that: My stated credentials and qualifications from the International Society of Arboriculture are in good standing and valid at the time of the assessment. I have personally conducted a visit to the property described in this report and inspected the subject tree(s). I have no past, present, or future interest in the property described in the report, the subject tree(s), or personal bias with any of the parties involved. I have provided my own opinions, analyses, and conclusions and they are based on current scientific understanding and industry accepted standards within the field of arboriculture. No one provided significant professional assistance to me, except as indicated within the report. My compensation for this assignment does not depend on providing a predetermined conclusion in my report. Please feel free to reach out with any questions. Respectfully, Signed on October 15, 2025 Daniel Seong, Chaparral Environmental Consulting LLC ISA Certified Arborist (WE-14831A) ISA Tree Risk Assessment Qualified Page 51 of 70 Page 52 of 70 Chaparral Environmental Consulting, LLC 21522 Carriso Rd Diamond Bar, CA 91765 chaparralenviro@gmail.com (909) 477-7344 TREE REPLANTING PLAN Prepared for Steven Chen 1382 Oceanaire Blvd San Luis Obispo, CA 93405 stvnenator@gmail.com (650) 224-9375 Prepared by Daniel Seong Chaparral Environmental Consulting, LLC chaparralenviro@gmail.com (909) 477-7344 Location 327 Los Cerros Dr San Luis Obispo, CA 93405 Submitted on December 23, 2025 Page 53 of 70 Intentionally left blank Page 54 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 23, 2025 Page 1 of 4 Objective This Tree Replanting Plan (TRP) was prepared to satisfy the compensatory planting requirements set by San Luis Obispo Municipal Code §12.24.090(J). The objective of the TRP will be to fulfill regulatory requirements, provide screening, and enhance the aesthetic value of the recipient property. Planting Site The proposed planting site is located within the backyard of a single-family residential property, on the western boundary of urban development within San Luis Obispo, CA. The area is located within USDA Hardiness Zone 10a, characterized by extensive periods of dry weather with brief periods of rainfall during the winter. The planting site was selected due to having full sun exposure and well drained soil, which are ideal conditions for the proposed species. There are no anticipated conflicts with existing infrastructure. The trees will be located in the backyard of private property, so there will be no interference with public right-of-ways or municipal infrastructure. The site is currently under construction. Plantings will occur after construction is complete and no more ground disturbance or site alteration is anticipated. Species Selection The proposed species to be planted are 3 individual fruitless olive trees (Olea europaea ‘HidshurtleƯ’). Olive trees are hardy, drought resistant that are well suited to the climate conditions of San Luis Obispo. The species does not tolerate inundation and requires fast draining soils along with full sun. In addition, the chosen cultivars are fruitless, which minimize litter and maintenance, as well as increasing productivity of canopy growth. In addition, olive trees are known for extreme longevity and high tolerance to drought conditions, making them ideal for the chosen site and climate. Lastly, the addition of drought tolerant vegetation to the recipient site provides resilience to adverse weather brought on by climate change. Stock Selection Nursery stock will be selected in accordance with the Guideline Specification for Nursery Tree Quality and ANSI Z60.1: American Standard for Nursery Stock. Emphasis will be placed on central leader dominance and the absence of girdling roots. Per §12.24.090(J), the size of the selected stock will be 0.75” to 1.5” diameter, in a 15-gallon container. Planting Techniques Installation will adhere to City of San Luis Obispo Tree Planting Standards and ANSI A300: Planting and Transplanting Standards. Prior to planting, the recipient site will be prepared by excavating the planting holes ahead of time. The planting holes will be 3 times the width of the root ball and the same depth as the root ball. The walls of the planting hole will be scored to eliminate glazing. The Page 55 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 23, 2025 Page 2 of 4 backfill will be amended with a blend of 85% native soil and 15% compost. Due to high wind exposure on the western boundary, heavy-duty 2”x 8’ lodgepole stakes will be installed in addition to the trees. Two stakes will be aƯixed to each tree, and tied suƯiciently taut without causing girdling. The ties will be placed as low on the trunk as feasible. The staked trees will be inspected to ensure that the tree can still flex in the wind without being toppled during heavy winds. Once the trees are established, the stakes will be removed. Once the trees are planted, the tree will be planted with the root flare exposed, and slightly elevated to compensate for settling. All trees will be spaced 20 feet apart to accommodate size at maturity, reduce risk of disease transmission through roots, and reduce mutual shading. The previously amended backfill will be placed and tamped down to eliminate air pockets without compacting the soil. Post-Planting Management After planting, trees will be managed on a yearly pruning cycle. Trees will be trained and selected for a single, upright leader. Competing leaders will be subordinated and removed over a period of several years. No more than 15% of the canopy will be removed in a single pruning cycle. Pruning will target competing leaders, crossing branches, crowded branches, and dead branches. Lateral branches selected to become permanent branches will be spaced suƯiciently to account for spacing at full maturity. The watering schedule will consist of watering on a monthly, as-needed basis to bring the top 1.5 inches of soil to field capacity. No additional watering will occur if the soil is found to already contain suƯicient moisture. Mulch comprised of organic material will be spread around the tree, covering an initial radius of 5 feet. The extent of the mulch ring will follow the drip line of the trees as they grow beyond a 5 foot radius. A 0.5 foot buƯer zone of bare soil will be maintained around the base of the trunk at all times. No fertilizer or other remedial soil or foliar treatment will be applied. Page 56 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 23, 2025 Page 3 of 4 Photographs Figure 1. Aerial overview of the site, viewed on Google Maps. The proposed planting area is circled in green. Page 57 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 23, 2025 Page 4 of 4 Figure 2. Overview of the 3 proposed planting spots, facing west. Figure 3. Overview of the 3 proposed planting spots, facing east. Page 58 of 70 Page 59 of 70 Page 60 of 70 Chaparral Environmental Consulting, LLC 21522 Carriso Rd Diamond Bar, CA 91765 chaparralenviro@gmail.com (909) 477-7344 TREE REPLANTING PLAN Prepared for Steven Chen 1382 Oceanaire Blvd San Luis Obispo, CA 93405 stvnenator@gmail.com (650) 224-9375 Prepared by Daniel Seong Chaparral Environmental Consulting, LLC chaparralenviro@gmail.com (909) 477-7344 Location 327 Los Cerros Dr San Luis Obispo, CA 93405 Submitted on December 30, 2025 Revised on March 12, 2026 Page 61 of 70 Intentionally left blank Page 62 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 1 of 6 Objective This Tree Replanting Plan (TRP) was prepared to satisfy the compensatory planting requirements set by San Luis Obispo Municipal Code §12.24.090(J). Species Selection A total of six (6) compensatory trees are proposed for installation. The proposed species to be planted are three (3) individual Little Ollie® dwarf olive trees (Olea europaea ‘Montra’), two (2) hollyleaf cherry (Prunus illicifolia), and one (1) African plum (Harpephyllum afrum). To avoid monoculture planting, three species from three diƯerent genera and families were selected. These species were chosen for their suitability to the climate conditions of San Luis Obispo, soil conditions on site, compatibility with wildlife, and size at maturity. Olive trees are hardy, drought resistant, evergreen trees known for extreme longevity and high tolerance to drought conditions, making them ideal for the chosen site and climate. In addition, the selected cultivar is a smaller variety of Olive tree that reach approximately 10 feet height and 8 feet canopy width at maturity, allowing suƯicient clearance space between plantings. Hollyleaf cherry is native to the chaparral habitat of coastal California that reaches up to 25 feet in height and 15 feet in width. The species is a drought-tolerant evergreen, making it well-suited to the conditions of San Luis Obispo. In addition, this species also produces large inflorescences and fruit that enhance the quality of wildlife habitat within the landscape. African plum is an evergreen tree that is comparatively larger than the other two species, reaching up to 50 feet in height and 30 feet width. The species is fairly hardy and thrives in full sun and dry soils, although a moderate amount of watering is beneficial until establishment. Like hollyleaf cherry, this species also produces fruit that attracts wildlife. Planting Site The proposed planting site consists of a single-family residential property, on the western boundary of urban development within San Luis Obispo, CA. The area is located within USDA Hardiness Zone 10a, characterized by extensive periods of dry weather with brief periods of rainfall during the winter. The dwarf olives will be installed in the north portion of the back yard and have no anticipated conflicts with existing infrastructure. The hollyleaf cherry trees will be planted adjacent to the driveway with a 7 foot setback to minimize conflict with pavement. Canopy growth is anticipated to extend into the driveway. However, structural pruning will be done to ensure that permanent scaƯold limbs will not interfere with the intended use of the driveway. All plantings will be set back so that the canopies at maturity will be 10 feet from the curb and avoid interference with the public right-of-way or municipal infrastructure. The site is currently under construction. Planting will occur after construction is complete and no further ground disturbance or site alteration is anticipated. Page 63 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 2 of 6 Stock Selection Nursery stock will be selected in accordance with the Guideline Specification for Nursery Tree Quality and ANSI Z60.1: American Standard for Nursery Stock. Standard stock (single-stem form) will be selected. Emphasis will be placed on central leader dominance and the absence of girdling roots. All selected stock will be planted in 15-gallon containers. Planting Techniques Installation will adhere to City of San Luis Obispo Tree Planting Standards and ANSI A300: Planting and Transplanting Standards. Prior to planting, the recipient site will be prepared by excavating the planting holes ahead of time. The planting holes will be 3 times the width of the root ball and the same depth as the root ball. The walls of the planting hole will be scored to eliminate glazing. The backfill will be amended with a blend of 85% native soil and 15% compost. Due to high wind exposure on the western boundary of the recipient site, 2 heavy-duty 2”x 8’ lodgepole stakes will be installed in addition to the trees. Two stakes will be aƯixed to each tree, and tied suƯiciently taut without causing girdling. The ties will be placed as low on the trunk as feasible. The staked trees will be inspected to ensure that the tree can still flex in the wind without being toppled during heavy winds. Once the trees are established, the stakes will be removed. The tree will be planted at an appropriate depth with the root flare exposed, slightly elevated to compensate for settling. All trees will be spaced appropriately, to reduce the risk of disease transmission through roots and mutual shading. The previously amended backfill will be placed and tamped down to eliminate air pockets without compacting the soil. Post-Planting Management After planting, trees will be managed on a yearly pruning cycle. Trees will be trained and selected for a single, upright leader. Competing leaders will be subordinated and removed over a period of several years. No more than 15% of the canopy will be removed in a single pruning cycle. Pruning will target competing leaders, crossing branches, crowded branches, and dead branches. Lateral branches selected to become permanent branches will be spaced suƯiciently to account for spacing at full maturity. The hollyleaf cherry trees will have an additional pruning objective to provide adequate vehicle clearance above the driveway. The watering schedule will consist of watering on a monthly, as-needed basis to bring the top 1.5 inches of soil to field capacity, until establishment. No additional watering will occur if the soil is found to already contain suƯicient moisture. For the African plum, watering will be done on a bi- weekly basis. Mulch comprised of organic material will be spread around the tree, covering an initial radius of 5 feet. Over time, additional mulch will be added so that the extent of the mulch ring will follow the drip line of the trees as they grow beyond the initial 5 foot radius. A 0.5 foot buƯer zone of bare mineral soil will be maintained around the base of the trunk at all times. No fertilizer or other remedial soil or foliar treatment will be applied. Page 64 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 3 of 6 Photographs Figure 1. Aerial overview of the site, depicting locations of proposed planting and size at maturity. Depicted trees are olive trees (green), hollyleaf cherry (orange) and African plum (purple). Page 65 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 4 of 6 Figure 2. Overview of dwarf olive proposed planting spots, facing west. Figure 3. Overview of dwarf olive proposed planting spots, facing east. Page 66 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 5 of 6 Figure 4. Overview of hollyleaf cherry proposed planting spot, replacing the Lemon-scented gum, seen from Los Cerros Dr, facing south. Page 67 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 6 of 6 Figure 5. Overview of hollyleaf cherry proposed planting spot, replacing the Lemon-scented gum, seen from Los Cerros Dr, facing south. Page 68 of 70 Chaparral Environmental Consulting, LLC Tree Replanting Plan on Los Cerros Dr December 30, 2025 Page 7 of 6 Figure 6. Overview of African plum proposed planting spot, seen from Los Cerros Dr, facing west. The lemon-scented gum in the background is proposed for removal. Page 69 of 70 Page 70 of 70