HomeMy WebLinkAboutAppendix C: Arborist ReportAppendix C:
Arborist Report
ARBORIST REPORT
July 26, 2022
6454.00
PROJECT
Terminal 101
South San Francisco, CA
PREPARED FOR
Steelwave, LLC
PREPARED BY
HMH
1570 Oakland Road
San Jose, CA 95131
William Sowa
ISA Certified Arborist #WE-12270A
TABLE OF CONTENTS
Page
Table of Contents 1
Introduction and Overview 2
Methodology 2
Summary of Findings 2
General Observations and Recommendations 4
Recommendations for Tree Protection During Construction 5
Maintenance Recommendations for Trees to Remain 6
Terms and Conditions 8
Exhibit A – Existing Tree Map 9
Table 1 - Tree Quantity Summary 10
Table 2 - Tree Evaluation Summary 11
Tree Photographs 14
HMH 1 of 15 7/27/2022
INTRODUCTION AND OVERVIEW
HMH was contracted to prepare an arborist report for a commercial site along Highway 101 off
Terminal Court in South San Francisco. There are exiting buildings in the center of the site with
surface parking making up most of the site on all four sides of the structures. Observations of the
current conditions suggests the site has been used for various commercial uses and surface
parking. The general health of most of the trees was observed to be moderate to poor. Our scope
of services includes locating, measuring DBH, assessing, and photographing the condition for
trees located within the limit of work illustrated on Exhibit A. Disposition and health
recommendations are based on current site conditions. Site development/design may affect the
preservation suitability.
METHODOLOGY
Our tree survey work is a deliberate and systematic methodology for cataloging trees on site:
1. Identify each tree species.
2. Note each tree’s location on a site map.
3. Measure each trunk circumference at 54” above grade per ISA standards.
4. Evaluate the health and structure of each tree using the following numerical standard:
5 - A healthy, vigorous tree, reasonably free of disease, with good structure and form typical of the species.
4 - A tree with slight decline in vigor, small amount of twig dieback, minor structural defects that could be
corrected.
3 - A tree with moderate vigor, moderate twig and small branch dieback, thinning of crown, poor leaf
color, moderate structural defects that may that might be mitigated with care.
2 - A tree in decline, epicormic growth, extensive dieback of medium to large branches, significant
structural defects that cannot be abated.
1 - A tree in severe decline, dieback of scaffold branches and or trunk, mostly epicormic growth;
extensive structural defects that cannot be abated.
0 - Tree is dead.
SUMMARY OF FINDINGS
HMH conducted a tree inventory of 16 trees located within the limit of work outlined in Exhibit A.
Five (5) of the trees inventoried are classified as protected trees under the City of South San
Francisco Tree Removal permit.
A protected tree is:
Any tree of the following species with a circumference of 75" or more when measured 54" above
natural grade.
Blue Gum (Eucalyptus globulus)
Black Acacia (Acacia melanoxylon)
Myoporum (Myoporum laetum)
Sweetgum (Liquidambar styraciflua)
Glossy Privet (Lingustrum lucidum)
Lombardy Poplar (Populus nigra)
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Any heritage tree of the following species with a circumference of 30" or more when measured at
54" above natural grade.
California Bay (Umbellaria californica)
Oak (Quercus spp.)
Cedar (Cedrus spp.)
California Buckeye (Aesculus californica)
Catalina Ironwood (Lyonothamnus floribundus var. asplenifolius)
Strawberry Tree (Arbutus spp.)
Mayten (Maytenus boaria)
Little Gem Dwarf Southern Magnolia (Magnolia grandiflora 'Little Gem')
Any tree other than the species listed above with a circumference of 48" or more when measured
54" above natural grade
A tree or stand of trees so designated based upon findings that it is unique and of importance to
the public due to its unusual appearance, location, historical significance
A stand of trees whereby each tree is dependent upon the others for survival
Table 1 - Tree Quantity Summary summarizes tree quantities by both species and size. Each
species that was inventoried as part of this scope is included. This is a useful tool for analyzing
the mixture of trees as part of the project. The size table is useful when calculating mitigation
requirements in the case of tree removal as well as aiding in determining tree maturity.
Table 2 - Tree Evaluation Summary lists each tree number, botanical name, common name, DBH,
circumference, ordinance trees, health rating, preservation suitability, general notes and
observations and recommendations.
See Exhibit A for Existing Tree Locations
See Table 1 for Tree Quantity Summary by species and size.
See Table 2 for Tree Evaluation Summary for sizes, notes and recommendations regarding each
tree.
HMH 3 of 15 7/27/2022
GENERAL OBSERVATIONS AND RECOMMENDATIONS
Species: Corymbia ficifolia (Red Flowering Gum)
Quantity: 1
Observations / Recommendations:
This tree is in moderate health and shape. It is showing sins of stress and some crown thinning.
It is also adjacent to a structure that overtime will crowd the east side of the canopy. As this is
the only specimen on the site if it was to be removed there would be no loss of aesthetics for the
site.
Species: Eucalyptus longifolia (Eucalyptus Tree)
Quantity: 2
Observations / Recommendations:
The two eucalyptus trees are in poor shape and structure. They should be removed.
Species: Juniperus californica (California Juniper)
Quantity: 8
Observations / Recommendations:
Often more associated as a shrub the California Juniper can create a substantial enough structure
to resemble a tree shape. These are older specimens that have grown to large enough trunk and
canopy size they are included in the report. They are in moderate to poor shape and have
naturalized along the freeway. As they are on the opposite side of the fence it may be possible
they are in Caltrans Right of Way an if removal was pursued they would probably need a different
process.
Species: Myoporum laetum 'Carsonii' (Coast Myoporum)
Quantity: 5
Observations / Recommendations:
The Cost Myoporum Trees are in poor shape and health. Most of them show crown die back and
structural defects. These trees are in a steady state of decline and should be removed. As noted
with the Junipers some of these may be in the Caltrans Right of Way and could require a different
tree removal process.
.
HMH 4 of 15 7/27/2022
RECOMMENDATIONS FOR TREE PROTECTION DURING CONSTRUCTION
Site preparation: All existing trees shall be fenced within or at the drip line (foliar spread) of the
tree. Depending on the location of the tree the fencing may not be able to be at the dripline.
Examples of this would be public right of way, near property lines or around existing structures to
remain. Where complete drip line fencing is not possible, the addition of straw waddles and orange
snow fencing wrapping the trunk shall be installed per the tree protection detail. The fence should
be a minimum of six feet high, made of galvanized 11-gauge wire mesh with galvanized posts or
any material superior in quality. A tree protection zone (TPZ) sign shall be affixed to fencing at
appropriate intervals as determined by the arborist on site. See tree protection detail for additional
information, including tree protection zone sign. If the fence is within the drip line of the trees, the
foliar fringe shall be raised to offset the chance of limb damage from active construction.
Active Construction: All contractors, subcontractors and other personnel shall be warned that
encroachment within the fenced area and dripline is prohibited without the consent of the certified
arborist on the job. This includes, but is not limited to, storage of lumber and other materials,
disposal of paints, solvents or other noxious materials, parked cars, grading equipment or other
heavy equipment. If construction activity needs to happen in the TPZ the fence can be moved
temporarily for delivery of construction materials. The contractor should make accommodations
to off load heavy construction material outside the foliar spread of the tree so there is no heavy
equipment needed that could cause damage to the canopy of the tree or compact the root zone.
The tree protection fencing should be reestablished per the plans and details immediately after
any activity through the TPZ. Penalties, based on the cost of remedial repairs and the evaluation
guide published by the international society of arboriculture, shall be assessed for damages to
the trees.
Grading/excavating: All grading plans that specify grading within the drip line of any tree, or
within the distance from the trunk as outlined in the site preparation section above when said
distance is outside the drip line, shall first be reviewed by a certified arborist. Provisions for
aeration, drainage, pruning, tunneling beneath roots, root pruning or other necessary actions to
protect the trees shall be outlined by an arborist. If trenching is necessary within the area as
described above, said trenching shall be undertaken by hand labor and dug directly beneath the
trunk of the tree. All roots 2 inches or larger shall be tunneled under and other roots shall be cut
smoothly to the trunk side of the trench. The trunk side should be draped immediately with two
layers of untreated burlap to a depth of 3 feet from the surface. The burlap shall be soaked nightly
and left in place until the trench is back filled to the original level. An arborist shall examine the
trench prior to back filling to ascertain the number and size of roots cut, so as to suggest the
necessary remedial repairs.
Remedial repairs: An arborist shall have the responsibility of observing all ongoing activities that
may affect the trees and prescribing necessary remedial work to ensure the health and stability
of the trees. This includes, but is not limited to, all arborist activities brought out in the previous
sections. In addition, pruning, as outlined in International Society of Arboriculture Best
Management Practices: Pruning and ANSI A300 Part 1 Standard Practices: Pruning, shall be
prescribed as necessary. Fertilizing, aeration, irrigation, pest control and other activities shall be
prescribed according to the tree needs, local site requirements, and state agricultural pest control
laws. All specifications shall be in writing. For pest control operations, consult the local county
agricultural commissioner's office for individuals licensed as pest control advisors or pest control
operators.
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Final inspection: Upon completion of the project, the arborist shall review all work undertaken
that may impact the existing trees. Special attention shall be given to cuts and fills, compacting,
drainage, pruning and future remedial work. An arborist should submit a final report in writing
outlining the ongoing remedial care following the final inspection.
MAINTENANCE RECOMMENDATIONS FOR TREES TO REMAIN
Regular maintenance, designed to promote plant health and vigor, ensures longevity of existing
trees. Regular inspections and the necessary follow-up care of mulching, fertilizing, and pruning,
can detect problems and correct them before they become damaging or fatal.
Tree Inspection: Regular inspections of mature trees at least once a year can prevent or reduce
the severity of future disease, insect, and environmental problems. During tree inspection, four
characteristics of tree vigor should be examined: new leaves or buds, leaf size, twig growth, and
absence of crown dieback (gradual death of the upper part of the tree). A reduction in the
extension of shoots (new growing parts), such as buds or new leaves, is a fairly reliable cue that
the tree’s health has recently changed. Growth of the shoots over the past three years may be
compared to determine whether there is a reduction in the tree’s typical growth pattern. Further
signs of poor tree health are trunk decay, crown dieback, or both. These symptoms often indicate
problems that began several years before. Loose bark or deformed growths, such as trunk conks
(mushrooms), are common signs of stem decay. Any abnormalities found during these
inspections, including insect activity and spotted, deformed, discolored, or dead leaves and twigs,
should be noted and observed closely.
Mulching: Mulch, or decomposed organic material, placed over the root zone of a tree reduces
environmental stress by providing a root environment that is cooler and contains more moisture
than the surrounding soil. Mulch can also prevent mechanical damage by keeping machines such
as lawn mowers and string trimmers away from the tree’s base. Furthermore, mulch reduces
competition from surrounding weeds and turf. To be most effective, mulch should be placed 2 to
4 inches deep and cover the entire root system, which may be as far as 2 or 3 times the diameter
of the branch spread of the tree. If the area and activities happening around the tree do not permit
the entire area to be mulched, it is recommended that as much of the area under the drip line of
the tree is mulched as possible. When placing mulch, care should be taken not to cover the actual
trunk of the tree. This mulch-free area, 1 to 2 inches wide at the base, is sufficient to avoid moist
bark conditions and prevent trunk decay. An organic mulch layer 2 to 4 inches deep of loosely
packed shredded leaves, pine straw, peat moss, or composted wood chips is adequate. Plastic
should not be used as it interferes with the exchange of gases between soil and air, which inhibits
root growth. Thicker mulch layers, 5 to 6 inches deep or greater, may also inhibit gas exchange.
Fertilization: Trees require certain nutrients (essential elements) to function and grow. Urban
landscape trees may be growing in soils that do not contain sufficient available nutrients for
satisfactory growth and development. In certain situations, it may be necessary to fertilize to
improve plant vigor. Fertilizing a tree can improve growth; however, if fertilizer is not applied
wisely, it may not benefit the tree at all and may even adversely affect the tree. Mature trees
making satisfactory growth may not require fertilization. When considering supplemental fertilizer,
it is important to consider nutrients deficiencies and how and when to amend the deficiencies.
Soil conditions, especially pH and organic matter content, vary greatly, making the proper
selection and use of fertilizer a somewhat complex process. To that end, it is recommended that
the soil be tested for nutrient content. A soil testing laboratory and can give advice on application
rates, timing, and the best blend of fertilizer for each tree and other landscape plants on site.
Mature trees have expansive root systems that extend from 2 to 3 times the size of the leaf
HMH 6 of 15 7/27/2022
canopy. A major portion of actively growing roots is located outside the tree’s drip line.
Understanding the actual size and extent of a tree’s root system before applying fertilizer is
paramount to determine quantity, type and rate at which to best apply fertilizer. Always follow
manufacturer recommendations for use and application.
Pruning: Pruning is often desirable or necessary to remove dead, diseased, or insect-infested
branches and to improve tree structure, enhance vigor, or maintain safety. Because each cut has
the potential to change the growth of (or cause damage to) a tree, no branch should be removed
without reason. Removing foliage from a tree has two distinct effects on growth: (1) it reduces
photosynthesis and, (2) it may reduce overall growth. Pruning should always be performed
sparingly. Caution must be taken not to over-prune as a tree may not be able to gather and
process enough sunlight to survive. Pruning mature trees may require special equipment, training,
and experience. Licensed and insured tree maintenance companies are equipped to provide a
variety of services to assist in performing the job safely and reducing risk of personal injury and
property damage and should be consulted for this type of work. (See also ANSI A300 Part 1
Pruning Standards- https://www.tcia.org).
Planting and Irrigation: Any new planting and irrigation that is to occur under the drip line of an
existing tree should be conducted with care to avoid the root system. Generally installation of an
irrigation mainline should be avoided under the dripline of the existing tree. Refer to the
Grading/Excavating section for installation of any irrigation lines to be installed under the drip line
of an existing tree. Any new planting should match the water use of the existing tree (as defined
by WUCOLS). The irrigation hydro zone for the new planting should also match the requirements
of the existing tree.
Removal: There are circumstances when removal is necessary. An arborist can help decide
whether or not a tree should be removed. Professionally trained arborists have the skills and
equipment to safely and efficiently remove trees. Removal is recommended when a tree: (1) is
dead, dying, or considered irreparably hazardous; (2) is causing an obstruction or is crowding and
causing harm to other trees and the situation is impossible to correct through pruning; (3) is to be
replaced by a more suitable specimen, and; (4) should be removed to allow for construction.
Pruning or removing trees, especially large trees, can be dangerous work. It should be performed
only by those trained and equipped to work safely in trees.
HMH 7 of 15 7/27/2022
TERMS AND CONDITIONS
The following terms and conditions apply to all oral and written reports and correspondence
pertaining to consultations, inspections and activities of HMH.
1. The scope of any report or other correspondence is limited to the trees and conditions
specifically mentioned in those reports and correspondence. HMH assumes no liability
for the failure of trees or parts of trees, either inspected or otherwise. HMH assumes no
responsibility to report on the condition of any tree or landscape feature not specifically
requested by the named client.
2. No tree described in this report was climbed, unless otherwise stated. HMH does not take
responsibility for any defects, which could have only been discovered by climbing. A full
root collar inspection, consisting of excavating the soil around the tree to uncover the root
collar and major buttress roots was not performed unless otherwise stated. HMH does
not take responsibility for any root defects, which could only have been discovered by
such an inspection.
3. HMH shall not be required to provide further documentation, give testimony, be deposed,
or attend court by reason of this appraisal or report unless subsequent contractual
arrangements are made, including payment of additional fees for such services as
described by HMH or in the schedule of fees or contract.
4. HMH guarantees no warrantee, either expressed or implied, as to the suitability of the
information contained in the reports for any reason. It is the responsibility of the client to
determine applicability to his/her case.
5. Any report and the values, observations and recommendations expressed therein
represent the professional opinion of HMH, and the fee for services is in no manner
contingent upon the reporting of a specified value nor upon any particular finding to be
reported.
6. Any photographs, diagrams, graphs, sketches or other graphic material included in any
report, being intended solely as visual aids, are not necessarily to scale and should not be
construed as engineering reports or surveys, unless otherwise noted in the report. Any
reproductions of graphic material or the work produced by other persons, is intended
solely for clarification and ease of reference. Inclusion of said information does not
constitute a representation by HMH as to the sufficiency or accuracy of that information.
7. Trees can be managed, but they cannot be controlled. To live near trees is to accept
some degree of risk. The only way to eliminate all risk associated with trees is to eliminate
all trees.
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124576 89101112131415163TERMINAL 101 PROJECT AREANOT A PART OF THIS REPORTHIGHWAY 101TERMINAL
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Existing Tree MapExhibit ANNNHMH 9 of 15 7/27/2022
Species Quantity % of Site
Corymbia ficifolia 16%
Eucalyptus longifolia 2 13%
Juniperus californica 8 50%
Myoporum laetum 'Carsonii'5 31%
Total Trees 16 100%
TABLE 1 - TREE QUANTITY SUMMARY
Tree Quantity by Species
HMH 10 of 15 7/27/2022
Suitability for Preservation is based on the followingHealth Rating543210Abbreviations and DefinitionsCD Codominant branchesCDB Dieback in CrownCRCrowdedD DeclineDBHDiameter at Breast HeightEG Epicormic GrowthEH Exposed HeartwoodH HazardousHD HeadedIB Included BarkLC Low crotchLN Leaning TreeML Multiple LeadersPT PhototropismS SuckersSD Structural DefectsSESevereSLSlightSR Surface RootsST StressWU Weak UnionTree is dead.Multiple central leaders originating below the DBH measurement site.Tree is bounded closely by one or more of the following: structure, tree, Etc. Naturally or secondary conditions including cavities, poor branch attachments, cracks, or decayed wood in any part of the tree that may contribute to structural failure.Structural defect where bark is included between the branch attachment so the wood can't join. Such defect can have a higher probability of failure.Condition where branches in the tree crown die from the tips toward the center.Watersprouting on trunk and main leaders. Typically indicative of tree stress.Measurement of tree diameter in inches. Measurement height varies by City and is noted above.TABLE 2 - TREE EVALUATION SUMMARYPrepared By: William Sowa ISA Certified Arborist WE-12270AA healthy, vigorous tree, reasonably free of disease, with good structure and form typical of the species.A tree in decline, epicormic growth, extensive dieback of medium to large branches, significant structural defects that cannot be abated.A tree with moderate vigor, moderate twig and small branch dieback, thinning of crown, poor leaf color, moderate structural defects that may that might be mitigated with care.Good - Trees with good health and structural stability that have the potential for longevity at the site.Moderate - Trees in somewhat declining health and/or exhibits structural defects that cannot be abated with treatment. Trees will require more intense management and will have a shorter lifespan than those in the 'Good' category.Poor - Trees in poor health or with significant structural defects that cannot be mitigated. Tree is expected to decline, regardless of treatment.Date of Evaluation: 7/14/2022DBH MEASUREMENT HEIGHT: 54"A tree with slight decline in vigor, small amount of twig dieback, minor structural defects that could be corrected.Weak union or fork in tree branching structure.A tree in severe decline, dieback of scaffold branches and or trunk, mostly epicormic growth; extensive structural defects that cannot be abated.Shoot arising from the roots.A tree that in it's current condition, presents a hazard.Forked branches nearly the same size in diameter, arising from a common junction an lacking a normal branch union.Tree shows obvious signs of decline, which may be indicative of the presence of multiple biotic and abiotic disorders. Tree exhibits phototropic growth habits. Reduced trunk taper, misshapen trunk and canopy growth are examples of this growth habit. Exposure of the tree's heartwood is typically seen as an open wound that leaves a tree more susceptible to pathogens, disease or infection. Roots visible at finished grade. Environmental factor inhibiting regular tree growth. Includes drought, salty soils, nitrogen and other nutrient deficiencies in the soil. Poor pruning practice of cutting back branches. Often practiced under utility lines to limit tree height.Tree leaning, see notes for severity.More than one upright primary stemIndicates the severity of the following term.Indicates the mildness of the following term.HMH11 of 157/27/2022
Protected Tree Any tree of the following species with a circumference of 75" or more when measured 54" above natural grade Blue Gum (Eucalyptus globulus) Black Acacia (Acacia melanoxylon) Myoporum (Myoporum laetum) Sweetgum (Liquidambar styraciflua) Glossy Privet (Lingustrum lucidum) Lombardy Poplar (Populus nigra) Any heritage tree of the following species with a circumference of 30" or more when measured at 54" above natural grade California Bay (Umbellaria californica) Oak (Quercus spp.) Cedar (Cedrus spp.) California Buckeye (Aesculus californica) Catalina Ironwood (Lyonothamnus floribundus var. asplenifolius) Strawberry Tree (Arbutus spp.) Mayten (Maytenus boaria) Little Gem Dwarf Southern Magnolia (Magnolia grandiflora 'Little Gem') Any tree other than the species listed above with a circumference of 48" or more when measured 54" above natural grade A tree or stand of trees so designated based upon findings that it is unique and of importance to the public due to its unusual appearance, location, historical significance A stand of trees whereby each tree is dependent upon the others for survivalHMH12 of 157/27/2022
TREE # BOTANICAL NAME COMMON NAMENATIVE / NON-NATIVEDBH (INCHES)CIRCUMFERENCE (INCHES) PROTECTED TREE HEALTHPRESERVATION SUITABILITYNOTES1Corymbia ficifoliaRed Flowering Gum Non Native 16 50 yes 3 Poor SD, CR2Myoporum laetum 'Carsonii'Coast Myoporum Non Native 12 38 no 2 Poor SD, CDB3Myoporum laetum 'Carsonii'Coast Myoporum Non Native 14 44 no 2 Poor SD, CR4Myoporum laetum 'Carsonii'Coast Myoporum Non Native 10 31 no 2 Poor SD, CR5Juniperus californicaCalifornia Juniper Native 8 25 no 2 Poor SD, Potentially offsite6Juniperus californicaCalifornia Juniper Native 12 38 no 2 Poor SD, Potentially offsite7Myoporum laetum 'Carsonii'Coast Myoporum Non Native 17 53 yes 3 Moderate SD, Potentially offsite8Juniperus californicaCalifornia Juniper Native 16 50 yes 3 Moderate SD, Potentially offsite9Juniperus californicaCalifornia Juniper Native 23 72 yes 3 Moderate SD, Potentially offsite10Juniperus californicaCalifornia Juniper Native 13 41 no 1 Poor SD, Potentially offsite11Juniperus californicaCalifornia Juniper Native 13 41 no 1 Poor SD, Potentially offsite12Juniperus californicaCalifornia Juniper Native 15 47 no 3 Moderate SD, Potentially offsite13Juniperus californicaCalifornia Juniper Native 8 25 no 2 Poor SD, Potentially offsite14Eucalyptus longifoliaEucalyptus Tree Non Native 21 66 yes 1 Poor SD, CDB15Eucalyptus longifoliaEucalyptus Tree Non Native 9 28 no 1 Poor SD, Potentially offsite16Myoporum laetum 'Carsonii'Coaast Myoporum Non Native825no2PoorSD, Potentially offsiteHMH13 of 157/27/2022
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