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HomeMy WebLinkAbout Arborist Report Mitigation 1 Arbor Care, Inc. arboricultural consulting & plant health care (626) 737-4007 mail@ArborCareInc.net DATE April 17, 2018 SUBJECT 910 Fallen Leaf Road: Evaluation of two protected Canary Island Pines, with mitigation recommendations. SUMMARY Two slightly overmature Canary Island Pines were erroneously removed without a permit. The property owner was familiar with the city’s tree ordinance protecting oaks and sycamores but unaware of the recently expanded ordinance that now includes all pine and many other species. An appraisal was done to determine the lost value of the pines, which is a total amount of $8,520. Recommendations for mitigation are given, which will provide for a successful long-term tree and replace the lost value to parity within a reasonable amount of time. Two 36” box container or one 48” box container size trees make for the most substantial replacements in the existing planter area, while ensuring good establishment and growth of the replacement trees. Several tree species are recommended as candidates for the replacements. BACKGROUND & ASSIGNMENT Two Canary Island Pines (Pinus canariensis) located in the front yard area were recently removed without a permit. The trees are Protected under the city’s tree ordinance (Ord. 2338) which was adopted in August 2016. The property was recently redeveloped and the Protected Tree Report that was prepared for the project, dated December 2013, included Oaks, Sycamores and trees located in the public right-of-way according to the tree ordinance at that time. Subsequently the property owner was unaware of the recently expanded tree ordinance that now includes all pine species. The city will review the tree removals and make a determination for adequate mitigation. This report is meant to assist in that review. The subject trees were appraised for their value and mitigation is recommended based on replacing the lost value with a tree or trees that will contribute to the landscape on an equal par with species that will succeed in the existing cultural conditions. I made my site visit to examine the site on April 10, 2016. I also used the original Protected Tree Report that I prepared in December 2013, as well as photographs of the subject trees taken from Google Maps for my analysis. 2 OBSERVATIONS Both trees are mature to slightly overmature Canary Island Pines. They each have the single central leader that is characteristic of this species but are losing the tapered (excurrent) form of a young to mature specimen and developing a more top heavy crown that typically comes during the tree’s overmature period. They are located ten feet from each other and one is located just inside the public right-of way setback area of the front yard. This tree was included in the original Protected Tree Report because of its location within the right-of-way and it is listed in the report as having a 26-inch trunk diameter, approximately 60 feet tall and an average canopy spread of 30 feet. The other tree is listed on the report’s site plan as also having a 26-inch trunk diameter, so it will be assumed that this measurement is accurate. The trees form a co-dominant canopy with a combined average spread of 35 feet. Although the one tree is technically a street tree, the setback of the front yard is not defined with a sidewalk and parkway strip, nor is the tree’s placement in the setback typical of a street tree. Both pines were most likely planted as a pair as part of a landscape design. It is unlikely that any defects or health issues were existing as the indicated in the Protected Tree Report and the images of the trees taken from Google Maps show the trees to be in good health and condition. The Google Maps images are recent as it shows the new home and landscape. The new landscape design has the trees situated in a planter that is densely planted with woody and herbaceous plants and turf grass outside of the planter area. This cultural setting is conducive for the requirements of Canary Island Pine. Google Maps images of the trees are on pages 5 and 6 of this report. PLANT APPRAISAL Method The Trunk Formula Method of plant appraisal was used to determine the value of the tree. This particular appraisal formula is the most widely accepted method in landscape and nursery industries to appraise the monetary value of trees considered too large to be replaced with nursery or field-grown stock. It was developed by the Council of Tree and Landscape Appraisers and is outlined in the Guide for Plant Appraisal, 9th edition. Four primary factors help determine the value of landscape plants: Size, Species, Condition and Location. Size is determined by measurement and comparison of common nursery material. Species ratings are compiled and published by the Western Chapter of the International Society of Arboriculture. The species rating often varies geographically, depending on the species' relationship with its environment. Condition and location are subjective, and expressed as a percentage determined by the plant appraiser relative to what would be considered a "high-quality" specimen. Condition rating is based on the subject plant's structural integrity and state of health prior to being destroyed or damaged. Location rating involves three components: The site of a property, which is based on market value; contribution, based on the plant's functional and aesthetic contributions; and placement, which is the positioning of the plant on the property in order to showcase or utilize its qualities. 3 I appraised the subject tree using the following factors: • Species rating was taken from the most regional information published in 2004 and coupled with more recent environmental condition. Canary Island pine has a relatively high water requirement and is highly susceptible to destructive bark beetles. Over the past decade drought has raised the need for water conservation and many new exotic bark beetle species have been introduced to Southern California; therefore the species rating for the appraisal has been reduced accordingly. • Replacement tree costs was determined from regional data and recent professional experience. • Condition is equivalent to an overmature tree in good health and structural condition. • For the Location, the site is rated as an upscale neighborhood with high home values. Contribution is based on the tree possessing aesthetic value as a skyline accent tree, good habitat for nesting birds, but little functional value for its afternoon shade. Placement is based on it being prominently positioned in the front yard, but somewhat hazardous in the fact that the tree produces large cones that are damaging when they fall. The proximity near the street presents a modest hazard to parked cars and pedestrians. Each tree has an appraised value of $4,260, for a total combined value of $8,520. The appraisal worksheet is located on page 7. RECOMMENDED MITIGATION Considerations for the existing trees in the front yard along with the cultural conditions of the newly completed landscape design, as well as replacing some of the contributory value of the removed trees, will help ensure a successful mitigation that will last for many years. The mitigation trees are assumed to be planted in the planter where the pines were located, which is designed for a tree. Here are some tree species that are suitable: Maidenhair Tree (Ginkgo biloba) – This tree can be maintained to have the same single central leader form as Canary Island Pine and grows quickly to the same height of 50-60 feet. Unlike the pine it is deciduous, but has brilliant fall color. It tolerates both moist and dry soil and is resistant to root rot diseases as well as destructive insects, particularly the newly introduced Polyphagous Shot Hole Borer (PSHB) beetle. This tree can also be planted in a close pairing similar to the subject pines. Jacaranda (Jacaranda mimosifolia) – A mature and healthy Jacaranda is located in the right-of-way setback area on the opposite side of the yard from where the pine trees were located. Planting a Jacaranda in the planter will compliment the existing Jacaranda and provide a bookend effect. Jacaranda can tolerate both moist and dry soil, has excellent summer flowering in warmer inland areas such as Arcadia and is resistant to diseases and insects including PSHB. The tree has a broad-spreading (decurrent) form so it is best to plant singularly to allow for the mature crown form. 4 Southern Magnolia (Magnolia grandiflora) – This reliable and evergreen tree is fast- growing to a height of 40 feet with an equal spread. It fits the cultural conditions, but requires some regular water for best performance. It is disease and pest resistant. Found regularly throughout the southern part of the United States, this species fits the new home’s Georgian-Colonial type architecture. Western Sycamore (Platanus racemosa) – This native tree performs best with regular watering, so it will succeed in the irrigated planter that is adjacent to turf. It grows quickly to 60 feet and can be planter in close pairs similar to the subject pines. It is highly susceptible to PSHB and many have been killed by the insect throughout the greater Los Angeles area in recent years. Although a 60” box container nursery grown tree would have an installed value to very near parity as the appraised value of each tree, I highly discourage this for mitigation. In my professional experience larger trees tend to have a higher chance of being root bound, which occurs at some point during the nursery production as the trees are moved up into larger boxes. A root bound tree remains stunted for many years, while a smaller tree with good root structure can catch up and outpace the growth in just a few years. Unfortunately, determining if a tree is rootbound is very difficult when accepting plant material and often isn’t discovered even during planting. Therefore, I highly recommend that the mitigation trees are of a more modest but still substantial 48” box size for a single tree mitigation such as Jacaranda or Magnolia, or 36” box size for a paired tree planting such as Maidenhair or Sycamore. 5 PHOTO: Looking east from Fallen Leaf Rd. at the subject trees. The Jacaranda located in the right-of-way setback at the opposite end of the yard is visible. Photo taken from Google Maps. 6 PHOTO: Looking west at the subject pine trees from Fallen Leaf Rd. Photo taken from Google Maps. 7 TRUNK FORMULA METHOD LOCATION:____________________________ TREE #:______ Field Observations 1. Species _____________________________________ 2. Condition _______ % 3. Trunk Diameter _______ inches 4. Location _____% = (Site _____% + Contribution _____% + Placement _____ %) ÷ 3 Regional Plant Appraisal Committee and/or Appraiser-Developed or Modified Information 5. Species rating ________ % 6. Replacement Tree Size: (Diameter) ________ inches (Trunk Area) ________ inches² 7. Basic Tree Cost (regional info.) $ ________ 8. Installation Cost $ ________ 9. Installed Tree Cost (#7 + #8) $ ________ 10. Unit Tree Cost (regional info.) $ ________ per inch² Calculations by appraiser using Field and Regional information 11. Appraised Trunk Area: (diameter² x 0.785) _______________ inches² (ATA) 12. Appraised Tree Trunk Increase = ___________ inches² [appraised trunk area (#11) _______ - replacement tree trunk area (#6) _______ ] 13. Basic Tree Cost = $ _______________ [trunk area increase (#12) ______ x Unit Tree Cost (#10) ______ + Installed Tree Cost (#9) ______ ] 14. Appraised Value = $ _______________ [Basic Tree Cost (#13) _____ x Species rating (#5) ____ x Condition (#2) ____ x Location (#4) ____ ] if the appraised value is $5000 or more the value is rounded to the nearest $100; if it is less, it is rounded to the nearest $10 3,500 63.16 35,537 .50 .40 .60 531 507.25 35,537 4,260 507.25 63.16 3,500 23.75 531 80 50 50 2,000 1,500 23.75 5.5 50 60 26 40 Pinus canariensis 910 Fallen Leaf Rd. 1 8 AUTHOR’S CREDENTIALS 9 CERTIFICATION OF PERFORMANCE I, Michael Crane, certify that: • I have personally inspected the tree(s) and the property referred to in this report and have stated my findings accurately. • I have no current or prospective interest in the vegetation or the property that is the subject of this report and have no personal interest or bias with respect to the parties involved. • The analysis, opinions, and conclusions stated herein are my own and are based on current scientific procedures and facts. • My analysis, opinions, and conclusions were developed and this report has been prepared according to commonly accepted arboricultural practices. • No one provided significant professional assistance to me, except as indicated within the report. • My compensation is not contingent upon the reporting of a predetermined conclusion that favors the cause of the client or any other party not upon the results of the assessment, the attainment of stipulated results, or the occurrence of any subsequent events. I further certify that I am a member in good standing of the American Society of Consulting Arborists and the International Society of Arboriculture. I have been involved in the field of Horticulture in a full-time capacity for a period of more than 20 years. Signed: ____________________________ Registered Consulting Arborist #440; American Society of Consulting Arborist Board Certified Master Arborist #WE 6643B; International Society of Arboriculture Licensed California Agricultural Pest Control Adviser #AA08269 April 21, 2018 Date: ______________________________