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: ______________________________