114-13 - City's Consulting Arborist report dated March 2013.pdf10121 Foothill Boulevard, Cupertino, California
Prepared by Michael L. Bench, Consulting Arborist March 22, 2013
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Michael L. Bench
Consulting Arborist (831) 594-5151
7327 Langley Canyon Road
Prunedale, California 93907
An Evaluation of the Existing Trees
10121 N. Foothill Boulevard
Cupertino, California
Assignment I was asked by Mr. George Schroeder, Assistant Planner, City of Cupertino, to prepare an
evaluation of the existing trees on the property at 10121 N. Foothill Boulevard,
Cupertino, California. Also, I was asked to include any trees on adjoining properties,
which may be impacted. Finally, I was asked to recommend acceptable replacement species and recommended locations.
Methods
I used a Diameter Tape (a Forestry service tape) to measure the trunks of the trees instead
of a standard measuring tape, because of the greater accuracy. The measurements were done at 4 ½ feet above soil grade, referred as DBH (Diameter at Breast Height ). The measurement was rounded to the nearest inch. The measurement for multi-stem
specimens was taken below the lowest fork on the trunk when possible in accordance
with the International Society of Arboriculture standards. The height and canopy spread
of each tree was estimated using visual references only. The estimated shape of the canopy relative to the other nearby trees has been added to the attached Site Plan. The trunks (or stems) of the neighboring trees could only be seen above the existing concrete
sound wall, and for this reason, their DBH measurements were estimated.
The condition of each tree was done by visual assessment only from a standing position without climbing or using aerial equipment. No invasive equipment was used. Consequently, it is possible that individual tree(s) may have internal defects, which are
not detectable by visual inspection. Invasive exploratory inspection and analysis is
beyond the scope of this evaluation.
Observations I visited the site on March 22, 2013.
There are 5 trees on this property and 13 trees on adjacent properties, which may be
impacted by construction on this site. I have marked the approximate locations of the 18 total trees on the attached Site Plan.
10121 Foothill Boulevard, Cupertino, California
Prepared by Michael L. Bench, Consulting Arborist March 22, 2013
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Trees # 1-8 have trunk diameters large enough to qualify them as Protected Trees. The row of 9 Italian cypress (Cupressus sempervirens) would take many, many years before they would have trunks large enough to clearly qualify them as Protected, but in
this case, they are used for screening, which is quite effective.
I included Tree # 9, a Lemon tree, because it hangs over the west side concrete sound wall, and because some people are very particular and protective about their fruit trees.
This photo shows the Lemon
Tree # 9 (left side) and the 9
Italian cypress Trees # 10-18.
The 18 total trees are listed by number on a Field Data Sheet, which follows this text.
This Data Sheet provides the basic information about each tree, including the trunk
diameter, height, spread, health, and an estimate of structural integrity. The health and structural integrity is rated on a scale of 1-5: (1) Excellent, (2) Good, (3) Fair, (4) Poor,
(5) Extremely Poor.
A working definition of these ratings are: (1) “Excellent” indicates outstanding Health
and Structural integrity without obvious structural weaknesses; (2) “Good” usually indicates fine Health but some observed Structural weakness, which can typically be
improved by cabling or pruning; (3) “Fair” usually indicates less than desirable but stable
Health and often indicates at least one significant structural weakness, which is not
observed to be immediately threatening; (4) “Poor” indicates less than average Health,
possibly a result of disease or insect infestation, presumed to be in slow decline with unlikely recovery; and (5) “Extremely Poor” indicates significantly declining health with
no hope of recovery, and possibly Hazardous structural integrity. Bear in mind that these
are rough definitions. There are many variations, all of which cannot be listed here.
Risks to the Existing Trees The Monterey pine (Pinus radiata) Trees # 1-5, located on this property are in Fair to
Good condition. All of these are mature specimens. In my experience, the Pinus radiata
species is very intolerant of root damage, especially when mature. It appears that all 5 of
these trees would suffer significant, if not severe, root damage as a result of construction. I would not expect any of these five Monterey pine trees to survive. None of the
Monterey pine Trees # 1-5 are of significant quality that they could not be replaced by
10121 Foothill Boulevard, Cupertino, California
Prepared by Michael L. Bench, Consulting Arborist March 22, 2013
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species better suited for the space, in my opinion. The neighboring Trees # 6-18 no doubt have roots extending onto this property. If the soil
adjacent to the West side property boundary were to be excavated or graded significantly,
these neighboring trees would not be expected to survive.
It would be essential for the survival of these neighboring trees that there would be no grading or excavation within 15 feet of the West side property boundary in the areas of
Trees # 6, 7, ad 8, and that there be no grading or excavation within 6 feet of the West
side property boundary in the areas of Trees # 9-18.
The residences on the west side of this property are at a higher elevation than the majority of this property, which slopes upward to those neighboring properties. I estimate the
slope to be approximately 3:1.
The steeper portion of the
slope is in the shadows of
this photo and difficult to
see.
There exists a post and
beam concrete wall along
the west side property
boundary. This wall has
been lifted by tree roots in a few locations.
I could not find on the Site Plans whether or not this concrete wall is intended to be repaired, left as it exists, or replaced. Replacement may be a significant issue for the
survival of the neighboring trees, especially if new piers would be required. This needs to
be clarified by the plans.
Replacement Trees The Site Plan shows potential locations for the planting of new trees. However, it appears
that screening plants would be necessary, especially for the south and west sides. In my
opinion, the preferred use of replacement trees would be for screening. I suggest the use
of Coast live oak (Quercus agrifolia) along the west side where there is greater planting
space, and the use of one of the following lower growing species, which can be managed in smaller spaces to be used on the south side:
Evergreen Species:
English holly (Ilex aquafolium)
Strawberry tree (Arbutus unedo) Sweet olive (Osmanthus fragrans)
Tawhiwhi (Pittosporum tenuifolium)
10121 Foothill Boulevard, Cupertino, California
Prepared by Michael L. Bench, Consulting Arborist March 22, 2013
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Hollywood juniper (Juniperus chinensis ‘Kaizuka’) California juniper (Juniperus californica) Paperbark melaleuca (Melaleuca linarifolia)
It will likely be difficult, if not impossible, to find some of these in 24 inch boxed sizes.
Three – fifteen gallon specimens are approximately equivalent to 1 – 24 inch boxed specimen.
Recommendations
I recommend for the survival of these neighboring trees that there would be no grading or
excavation within 15 feet of the West side property boundary in the areas of Trees # 6, 7, ad 8, and that there be no grading or excavation within 6 feet of the West side property boundary in the areas of Trees # 9-18. Replacement trees could be planted in these areas,
but these must be no trenching for irrigation within these areas near the neighboring trees.
Respectfully submitted,
Michael L. Bench, Consulting Arborist
International Society of Arboriculture Certification # WE 1897A
American Society of Consulting Arborists Member
10121 Foothill Boulevard Cupertino California
Field Data Sheet
Tree Name DBH Canopy
Height
Canopy
Spread
Health Structura
l
Integrity
Overall
Condition
Notes
1 Monterey pine
(Pinus radiata)
15 50 25 1 3 Fair/Good
2 Monterey pine 21 60 35 1 3 Fair/Good Extended limbs
3 Monterey pine 22 50 30 1 4 Fair Co-Dominant Leaders
4 Monterey pine 27 50 35 1 4 Fair Co-Dominant Leaders
5 Monterey pine 21/15 65 35 1 3 Fair/Good
6 Deodar cedar
(Cedrus deodara)
24 (E)55 40 1 2 Good
7 Canary Island pine
(Pinus canariensis)
18 (E)70 30 3 4 Fair/Poor Co-Dominant Leaders;
Die-Back Top 6 feet
8 Blue atlas cedar
(Cedrus atlantica glauca)
20 (E)65 35 2 2 Fair Competing Leaders
9 Lemon
(Citrus species)
8 (E)15 15 1 2 Good
10 Italian cypress
(Cupressus
sempervirens)
6 (E)30 10 1 1 Excellent
11 Italian cypress 6 (E)30 10 1 1 Excellent
12 Italian cypress 6 (E)30 10 1 1 Excellent
13 Italian cypress 6 (E)30 10 1 1 Excellent
14 Italian cypress 6 (E)30 10 1 1 Excellent
15 Italian cypress 6 (E)30 10 1 1 Excellent
16 Italian cypress 6 (E)30 10 1 1 Excellent
17 Italian cypress 6 (E)30 10 1 1 Excellent
18 Italian cypress 6 (E)30 10 1 1 Excellent
INDEX
DBH = Diameter in
Inches at Breast Height
(54 inches above grade)
Canopy Height in Feet
(Approx.)
Canopy Spread in Feet
(Approx.)
Hlth = Health
(1-5 = Good to Poor)
Strc = Structure
(1-5 = Good to Poor)
(E) = Estimated
Prepared by Michael Bench Consulting Arborist March 22, 2013