Item 4 - Exhibit 6-7D avid L. Babby, R egistered Consulting A rborist® May29, 2015
SECTION
1.0
2.0
3.0
4.0
5.0
5.1
5.2
5.3
6.0
EX HIBIT
A
B
c
TABLE OF CONTENTS
INTRODUCTION ............................................................................. 1
TREE COUNT AND COMPOSITION ............................................... 2
SU ITAB ILITY FOR PRESERVATION ................................................ 4
REVIEW OF POTENTIAL IMPACTS .............................................. 5
TREE PROTECTION MEASURES •••••••••••••••••••••••••••••••••••••••••••••••• 6
Design Guidelines ........................................................................ 6
Before Demolition, Grading and Construction ........................... 9
During Demolition, Grading and Construction ........................... 9
ASSUMPTIONS AND LIMITING CONDIT I ONS ............................. 12
EXHIB ITS
TITLE
TREE INVENTORY TABLE (three sheets)
SITE MAP (one sheet)
PHOTOGRAPHS (four sheets)
David L. Babby, R egistered Co ns ulting Arboris t® May 29,2015
1.0 INTRODUCTION
The Town of Los Gatos Co mmunity Development Department has retained me to prepare
this Arboris t Report in connection with the proposed new residence, with basement, at
18151 Overlook Road , Lo s Gatos. Specific tasks conducted are a s follows:
• Visit the site, performed on 5/21/15, to identify 15 "protected trees" 1 situated either
within the project site, along the street frontage , or on neighboring properties and
having trunks immediately adjacent to and /or canopies overhanging the site.
• Determine each tree's trunk diameter at 54 inches above grade. Diameters are
rounded to the nearest inch , and trees li sted with more than one diameter are formed
by multiple trunks.
• Estimate average canopy spreads (rounded to the nearest fifth).
• Ascertain each tree's health and structural integrity, and assign an overall condition
rating (e.g. good , fair, poor or dead).
• Rate each tree's suitabi lity for preservation (e .g. high, moderate or low).
• Obtain photographs ; see Exhibit C .
• Assign tree numbers in a sequential pattern, and plot those numbers and roughly
approximate locations on the site map in Exhibit B (base map being Sheet A 1, the
Site & Drainage Plan , dated 9/22114 , by Chri s Spaulding Architect).
• Affix round-metal tags with corresponding, engraved numbers to the trunks or limbs
of accessible tree s. For inaccessible trees on neighboring properties , tags were affixed
to wood fence s adjacent to re spective tree trunks .
• Review the set of project plans, prepared by C hris Spaulding Architect, s tamp dated
3/30/15 , to identify potential impacts to inventoried trees.
• Provide measures to help avoid or mitigate impacts to retained or rem oved trees.
• Prepare a written report containing the above information, and submit via email as a
PDF document.
1 Pursuant to Se ction 29 .10 .0960 of the Town 's Municip a l Code, a "pro tected tree " has a trunk with a
diameter ~4" at three feet above g rade . Fruit-or nut-bearin g trees with trunk diameters less th an 18" are
exempt (Section 29 .1 0 .0970).
18 151 Overlook Road , L os Ga tos Page 1 of12
Tow n of L os Gatos Community De velopment Departm ent
David L. Babby, R egistered Consulting Arborist® May 29,201 5
2.0 TREE COUNT AND COMPOSITION
Fifteen (15) trees of eight various species were inventoried fo r this report. They are
se quentially numbered as #1 thru 15, and the ta ble below identifies their names, assig ned
numbers, counts and percentages.
%OF
NAME TREE NUMBER(S) COUNT TOTAL
Coast Jive oak 6 ,7 ,11 ,14 4 27%
Deodar cedar 1 1 7%
European beech 4 1 7%
Evergreen pear 5 1 7%
Glossy privet 9, 10, 13 3 20%
Monterey pine 2,8, 12 3 20%
Pacific wax myrtle 3 1 7%
Western redbud 3 1 7%
Total 15 100%
As illu strated in the above table , the tree la ndscape o n an d surro unding the si te 1s
populated predo minantly by coast live oak , followed by privet a nd Monterey pine.
Specific information regarding each tree is presented within t he table in Exhibit A. The
trees' corresponding numbers and approximate locations can be viewed on the s ite map in
Exhib it B, and photographs are presented in E xh ibit C.
Tree #3 , a small re dbud , is situated within the public right-of-way along O verl ook Road
and is regarded as a street tree.
18151 Overlook Road, Los Gatos Page 2 of12
Town of L os Gatos Community Development Departmen t
David L. Babby, Registered Consulting Arborist® May29, 2015
Nine (9) trees have trunks originating on neighboring properties, and due to their
prox imity to the project site , were inventoried to achieve conformance with Section
29.10.0995 of the Town Code); they include #1, 4, 6-10, 12 and 13 .
Ten (10) trees are not shown on the project plans, and their locations depicted on the map
in Exhibit Bare only roughly approximate and should not be construed as being surveyed;
they include #1, 4, 6-10, 12, 13 and 15 (accounts for all those on neighboring properties
plus #15).
Other' trees located throughout the site were not inventoried due to having trunks with
diameters less than four inches .
18151 Overlook Road, Los Gatos Page 3 of12
Town of Los Gatos Comm unity Developm ent Department
Da vid L. Babby, Registered Consulting Arborist® May29 , 2015
3.0 SUITABILITY FOR TREE PRESERVATION
Each tree has been assigned e ither a "high," "moderate" or "low" suitabili ty for
preservation rating as a means to cumulatively measure its ex isting health, structura l
integrity, anticipated life span, location, size, particular species, tolerance to construction
impacts , growing space, and safety to property and persons within striking distance.
Descriptions of these ratings are presented below; the high category is comprised of no
trees, the moderate category six (o r 40%), and the low category nine (o r 60%).
High: Applies to none.
These trees appear relatively healthy and structurally stable ; have no apparent, significant
health iss ues or structural defects; present a good potential for contributing long-term to the
site; and require only periodic or regular care and monitoring to maintain their lo ngevity
and structural integrity. They are typically the most suitable for retaining and incorporating
into the future landscape.
Moderate: Applies to trees #1, 4, 6, 8, 11 and 14 .
These trees contribute to the site, but at leve ls less than those assigne d a good suitab ili ty;
may have health and/or structura l issues that can potentially be reaso nably address ed a nd
properly mitigated; and frequent care is ty pically required for their remaining lifespan.
They might be worth retaining , if provided proper care, but not see mingly at s ignificant
expense or major de sign revisions.
low: Applies to trees #2, 3, 5, 7, 9, 10, 12, 13 and 15.
These trees have serious or significantly weakened health and/or structural defects that are
expected to worsen re gard le ss of tree care measures emp loyed (i.e . beyond like ly
recovery). Removal of those located within the site is reco mmended t o improve the tree
landscape and /or site safety.
18151 O verlook Road, Los Gatos Page 4 of12
Town of Los Gatos Community Development Departm ent
David L. Babby, R egistered Co ns ulting Arborist® May29, 2015
4.0 REVIEW OF POTENTIAL IMPACTS
Implementation of the proposed de s ign allow retention of all inventoried trees, but presents
significant impacts to a few, namely #3 and 6. Tree #3 is a small redbud with a poor
structure, and excavation for constructing the new driveway will extend up to its trunk;
based on its condition, remo val is the appropriate di s pos ition.
Tree #6 is a large coast live oak originating from the neighboring eastern property.
Excavation for the proposed lightwell along the home's east s ide will result in severe root
loss, and as a result, subject the tree to instability and/or premature decline. To avoid thi s,
the lightwell des ign requires revi sion to achieve a minimum protection zone of nine to ten
feet west of the trunk, and from this point towards north and south , up to 15 feet from the
trunk; the protection zo ne mu s t remain free fr om any excavation, overexcavation, fill ,
compaction, trenching, or othe r soil disturbance, including for s horing (and stitch piers).
I also recommend onsite trees #2, 5 and 15 are removed. Tree #2 is a declining Monterey
pine with a poor structure , #5 is a small evergreen pear also with a poor stru cture, and # 15
is a short tree anticipated to be removed during excavation for the basement.
Tree #4 is s ituated in close proximity t o the ne w parking space. Given a distinct grade
differential between the shared fence and ho me , to include a planter, short rock wall , a nd
level walk belo w planter, there unlikely are s ignificant roots within the existing walk, but
will be within the planter. Based on thi s, where beneath the tre e's existing canopy, the
future parking s pace/driveway s hould be entire ly beyond (east of) the outer edge of
existing pl anter and rock w a ll , including f or any overexcavation; i.e. maintain exi sting
grade within entire planter width and beyo nd wall (note that dimens ions and grades of
existing conditions are need ed , a nd not currently shown in the s ite pla n).
A summary of the prior information is as follows:
• Removals (four in total): #2, 3, 5 and 15.
• Retained (11 in total): #1, 4 and 6-14.
• Revise the lightwell and building des ign fo r achieving a reasonable chance of
s urvi va l a nd rootin g stability for tree #6 .
• Achieve setback noted above for the parking space adjacent to tree #4 .
181 51 Overlook Road, Los Gatos Pa ge 5 of12
Town of Los Ga tos Co mmunity Developmen t Departm ent
David L. Babby, R egistered Consulting Arborist® May29, 2015
5.0 TREE PROTECTION MEASURES
This section presents recommendations for achieving the protecti o n of retained trees
throughout construction. They should be carefully followed , are subject to revi s ion upo n
reviewing revised or additional project plans , and I should be consulted in the event any
measure cannot be feasibly implemented. Please note all referenced distances from trunks
are intended to be from the closest edge (face of) of their outem1ost perimeter at soil grade.
5.1 Design Guidelines
I. Designate a Tree Protection Zone (TPZ) to be the section of existing unpaved
ground beneath or beyond a tree's entire canopy, and for #4 and #6, as specified in
Section 4.0 of this report. A TPZ is where the following activities, but not necessarily
limited to , shall be avoided: trenching, so il scraping, compaction, mass grading,
finish-grading, overexcavation, subexcavation, tilling, ripping, swales, bi oswales,
storm drains, dissipaters, dry equipment cleaning, stockpiling and dumping of
materials, and equipment/vehicle operation. In the event an impact encroaches
slightly within a setback, it can be reviewed on a case-by-case basis to determine
whether measures can sufficiently mitigate the impacts to les s -than-s ignificant level s.
2 . For trees #4 and 6 , implement the design recommendations provided in Section 4.0.
3. Where beneath the canopies of trees #6 and 14, confine overexcavation, compaction
and other soil disturbance to within 24 inches beyond the basement wall and first
floor foundation (including the drilling of piers for shoring).
4 . To achieve the above, shoring is critical to avoid overexcavation beyond the
ba se ment wall and maintain setbacks. The shoring design should not require the loss
or large limbs or branches during operation of a pile driver or drill rig for shoring.
(and soil nailing and shotcrete utilized should a conflict exist).
5. The permanent and temporary drainage design , including downspouts, should not
require water being discharged towards a tree's trunk.
18151 Overlook Road, Los Gatos Page 6 of12
Town of Los Gatos Community De velopment D epartm ent
David L . Babby , R egistered Consulting Arboris t® May 29, 2 015
6. Add the assigned numbers to a ll site-related plans . The approximate trunk
locations of #1, 4, 6-10, 12, 13 and 15 should also be added , as well as additional
information regarding the grade differential, planter width and wall location beneath
#4's canopy.
7. On the demolition plan, specify that all below ground existing and unused pipes,
vaults and lighting shall be abandoned and cut off at existing soil grade where
within a TPZ (rather than being dug up and causing root damage).
8 . Swales should be established well-beyond tree canopies . Where necessary within,
they shou ld be as far from the trunks as possible, require no more than a two-to
three-inch deep cut or fill, avoid severing roots ~two inches in diameter, and not be
compacted (foot-tamping is acceptab le).
9 . The erosion control design should consider that any straw wattle or fiber rolls
require a maximum vertical soi l cut of two inches for their embedment, and are
established as close to canopy edges as possible (and not against a tree trunk).
10 . Per Section 29 .10.1000(C.l) of the Ordinance, a copy ofthis report (or updated one)
must be incorporated into the fina l set of project plans; titled Sheets T -1, T -2, etc.
("Tree Protection In structions"); and referenced on all site-related project plans .
I I. On Sheet A 1, add protection fencing for trees #4 and 6 to be along the outside
eastern edge of the existing wall for #4, and five feet from the proposed home
foundation or basement wall for #6; see Exhibit B for an illustration.
12 . A root zone buffer, for foot -traffic only , should also be specified on Sheet A I for
trees #6 and 14, to be between protection fencing and the basement wall or
foundation. It shall comprise a six-to eight-inch layer of coarse wood chips manually
spread on unpaved ground, and to create a sturdy walking surface, can be covered by
plywood sheets of at least %-inch thick and secured together. For tree #6, it should
be installed prior to demoliti on, and for #4, immediately fo ll owing removal of the
existing rear patio .
18 151 Ove rlook Road, Los Gatos P age 7 of12
Town of Los Gatos Community D e velopment D epartment
David L. Babby, R egistered Consulting Arborist® May 29, 2015
13 . The landscape design should conform to the following additi onal guidelines:
a . Plant material installed beneath the canopies of the oaks sho uld be dro ug ht-
tolerant, limited in amo unt , and planted at least five or more feet from their
trunks. Plant ma terial in stalled beneath the canopies of all other trees should be
at least 24 to 36 inches from their trunks.
b . Irrigation beneath the oak canopies should not be applied within a di stance of
five times their trunk diameters. Irrigation for new plant materi a l beneath their
canopies should be low-vo lume, applied irregularly (s uch as on ly once o r twice
per week), and temporary (such as no more than three years).
c. Irrigation and lighting features (e.g. main line , lateral lin es, va lv e boxes,
wiring and controllers) should be establi s hed beyond TPZs. In the event thi s is
not feasible , they may require be ing installed in a radial directi o n to a tree 's
trunk, and terminate a spec ific di stance from a trunk (versus crossing past it).
d. Ground cover should be comprised (partially or entire ly) of a three-to four-
inch depth of coarse wood chips or other high-quality mulch (gorilla ha ir, bark
or rock, stone , cobble , gravel , black plastic or other synthetic gro und cover
should be avoid ed). Mulch sho uld rem a in s ix inches fro m the trees' trunks .
e. Tilling, ripping and compaction within TPZs s hould be avoided.
f. Bender board or othe r edging materi a l proposed beneath the canop ies should be
established on top of existing so il grade (such as by us ing vertical stakes).
14. Mitigation is nece ssary t o compensate for the rem ova l of protected trees, a nd
Section 29 .I 0.0985 can be used as the framework for det ermining amounts and sizes .
The trees shall be planted pri or to final inspection, double-staked with rubbe r tre e ties
(may not be necessary for trees of 36-inch box si ze and larger), a nd a ll forms of
irrigation be of a n aut omatic drip or soake r hose system placed on the so il s urface
and not in a s leeve. Additi o na ll y , to achieve the gre atest assurance of proper
installation, a ll new trees shall be installed, includin g necessary irrigation, by an
experi ence d Cali fo rni a State-licensed landscape contractor or tree-service company.
18151 Overlook Road, Los Gatos Page 8of1 2
Town of Los Gatos Community D evelopment D epartment
David L. Babby, R egist ered Consulting Arborist® May 29, 2015
5.2 Before Demolition, Grading and Construction
15. Manually restore the soil grade at the rear of the site ; the ground should be
'smoothed' and leveled out, being careful not to excavate so il and roots.
16. Spread a four-to five-inch layer of coarse wood chips ('4-to %-inch in size) from a
tree-service company over the ground within the property's rear section.
17 . Establish the root zone buffer for tree #6.
18 . The root collars of trees #11 and 14 must be fully cleared of rock and soil on all
sides (360°), and the work performed by a professional and state-licensed tree service
either through hand-digging or the use of an Airspade.
19. Establish tree protection fencing to restrict access into TPZs, and where along
future foundations , no farther than five feet from the basement wall; locations are
identified on Exhibit B. This fencing shall remain throughout construction, and
consist of five-to six-foot high chain link mounted on eight-foot tall , two-inch
diameter galvanized steel posts that are driven into the ground.
20. Pursuant to Section 29.10.1005(a)(4) of the Town Code, 8.5-by 11 -inch warning
signs shall be affixed and prominently displayed on each side of fencing opposite the
trees ' trunks: "WARNING -Tree Protection Zone -this fence shall not be removed
and is subject to penalty according to Town Code 29.10.1025." These s igns should
be intact prior to commencing demolition.
5.3 During Demolition, Grading and Construction
21 . Supply water to the root zones of #4, 6 and 14 every three to four weeks throughout
the entire construction process, at an amount of five to ten gallons per inch of trunk
diameter. Various application methods include either flooding the in side of a 12-inch
tall berm formed around or near a canopy's perimeter, using soaker hoses , or through
deep-root injection. For #4 and 6, watering only on the project site is sufficient.
22. A void using tree trunks as winch supports for moving or lifting heavy loads.
18151 Overlook R oad, Los Gatos Page 9of12
Town of Los Gatos Community Development Department
David L. Babby, Register ed Cons ulting Arborist® M ay 29, 2015
23. The staging area and route(s) of access should be established beyond TPZs.
24. Excavation for section of drive (parking space location) beneath #4's canopy should
first be performed by a one-foot wide trench being manually dug along the
perimeter of where soil excavation will occur closest to the tree's trunk, and down to
the required subgrade depth (to avoid roots breaking and being damaged closer to the
trunk than otherwise needed). Roots encountered with diameters of 2:two inches shall
be cleanly severed by hand (at 90° to the direction of root growth) against the tree
side of the trench. All soil beyond the trench (i.e. away from the tree) can then be
mechanically excavated using heavy equipment, and remaining outside the fenced
area(s). Alternatively, the use of a stump grinder could be utilized precisely where a
curb/gutter and any overcut (12" max) will be established.
25. Any approved digging or trenching within a TPZ shall be manually performed
without the use of heavy equipment or tractors operating on unpaved ground beneath
canopies.
26 . A void damaging or cutting roots with diameters 2:two inches. Should roots of this
size be encountered, within one hour of exposure , they should either be covered by
burlap that remains continually moist until covered by soil. If they are approved for
cutting, cleanly severe at 90° to the angle of root growth against the cut line (using
toppers or a sharp hand saw), and then immediately after, the cut end either buried
with soil or covered by a plastic sandwich bag (and secured using a rubber band, and
removed just before backfilling).
27. Tree pruning shall only be performed in accordance with ANSI A300-2001
standards, by a California licensed tree-service contractor (D-49) that has an ISA
certified arborist in a supervisory role , carries General Liability and Worker's
Compensation insurance, and abides by ANSI Z133 .1-2006 (Safety Operations).
28 . Removing existing hardscape and home within and near a TPZ, such as for tree
#14 , must be carefully performed to avoid excavating roots and so il during the
process (and above-ground portion of a tree).
18151 Overlo ok Road, Los Gatos Page 10of12
Town of Los Gatos Community Development Departm ent
David L. Babby, R egistered Consulting Arboris t® May 29, 2015
29 . The root zone buffer for tree #14 shall be installed immediately following
demolition of the existing rear patio (completed prior to basement excavation).
30. Any fence posts to be established within a TPZ must be carefully designed to avoid
potential significant impacts. In doing so, I recommend they are planned to be at
least two to three feet from a trunk , minimized in diameter, and spaced as far apart as
possible (e.g . at least five plus feet apart). The design should specify that the post
holes are manually dug using a post hole digger or shovel, and roots two inches and
greater in diameter retained and protected during the process (in the event a root of
this size is encountered during digging, the hole should be shifted over 12 inches and
the process repeated).
31. Spoils created during digging shall not be piled or spread on unpaved ground within
a TPZ . If essential , spoils can be temporarily piled on plywood or a tarp.
32 . Dust accumulating on trunks and canopies during dry weather periods should be
periodically washed away (e .g. every two to three months).
33. Avoid disposing harmful products (such as cement, paint, chemicals, oil and
gasoline) beneath canopies or anywhere on site that allows drainage within or near
TPZs. Herbicides should not be used with a TPZ; where used on site, they should be
labeled for safe use near trees. Liming shall not occur within 50 feet from a trunk.
34. Great care must be taken by equipment operators to position their equipment to
avoid the trunks and branches of trees, including the scorching of foliage (including
along the road).
35. Fertilization may benefit the trees' health, vtgor and appearance . If applied,
however, soil samples should first be obtained to identify the pH levels and nutrient
levels so a proper fertilization program can be established. I further recommend any
fertilization is performed under the direction and supervision of a certified arborist,
and in accordance with ANSI A300 (Part 2)-2004 Fertilization standards.
18 151 O verlook Road, Los Gatos Page 11 ofl2
Town of L os Gatos Community D evelopment D epartment
David L. Babby, R egis tered Consulting Arborist® May29, 2015
EXHIBIT A:
TREE INVENTORY TABLE
(three sheets)
18151 Overlook R oad, Los Gatos
Town of Los Gatos Community Development Department
(
David L. Babby, Registered Consulting Arboris t® May29, 2015
EXHIBIT B:
SI TE MAP
(one sheet)
18151 Overlook Road, Los Gatos
Town of Los Gatos Comm unity D evelopm ent Departm ent
David L . Bobby, R egistered Consulting Arborist® May29, 2015
EXHIBIT C:
PH OTOG RAP HS
(four sheets)
Ph oto Index
Page C-1: Trees #1 thru 6 Page C-3 : Trees #10 thru 13
Page C-2: Trees #6 thru 9 Page C-4: Trees #14 and 15
18151 Overlook Road, Los Gatos
Town of Los Ga tos Community Development Departm ent
This Page
I ntentional/y
Left Blank
David L. Babby, R egistered Consulting Arborist® September 21 , 2015
SECTION
1.0
2.0
3.0
4.0
5.0
5.1
5.2
5.3
6.0
EXHIB IT
A
B
c
TABLE OF CONTENTS
TITLE PAGE
INTRODUCTION ••••••••• •••••• ••. •••••• •••••• •••••••••• ••• ••• •.. • ••. ••••.•••• •••••••••••• ••. 1
TREE COUNT AND COMPOSITION ............................................... 2
SUITABILITY FOR PRESERVATION ................................................ 4
REVI EW OF POTENTIAL IMPACTS .............................................. 5
TREE PROTECTION MEASURES ................................................ 6
Design Guidelines ........................................................................ 6
Before Demolition, Grading and Construction ........................... 9
During Demolition, Grading and Construction ........................... 10
ASSUMPTIONS AND LIMITING CONDITIONS ............................. 13
EXHIBITS
TITLE
TREE INVENTORY TABLE (three sheets)
SITE MAP (one sheet)
PHOTOGRAPHS (four sheets)
David L. Babby , R egistered Consulting Arborist® September 21, 201 5
1.0 INTRODUCTION
The Town of Los Gatos Community Development Department has retained me to review
the current set of plans and update my prior 5/29/15 report in connection with the proposed
new residence , with basement, at 18151 Overlook Road , Los Gatos. Specific tasks
conducted for this and the prior report are as follows:
• Review the current set of plans, stamp dated 8/5/15 by the Town.
• Visit the site, performed on 5/21 /15 , to as sess potential impacts by identify 15 tree s
situated either within the project site, along the street frontage , or on neighboring
properties and having trunks immediately adjacent to and /or canopies overhanging
the site. A subsequent visit was performed on 9116/15 to asse ss potential impacts by
implementing the current set of plans .
• Determine each tree's trunk diameter at 54 inches above grade. Diameters are
rounded to the nearest inch, and trees listed with more than one diameter are formed
by multiple trunks.
• Estimate average canopy spreads (rounded to the nearest fifth).
• A scertain each tree's health and structural integrity, and assign an overall condition
rating (e.g. good, fair, poor or dead).
• Rate each tree's s uitability for preservation (e.g. high, moderate or low).
• Obtain photogra ph s; see Exhibit C.
• Assign tree numbers in a sequential pattern, and plot those numbers and roug hly
approximate location s on the site map in Exhibit B (base m a p being Sheet A l , the
Site & Drainage Plan , d ated 9/22114 , by Chris Spaulding Architect).
• Affix round-metal tags with corresponding, engraved numbers to the trunks or limbs
of accessible trees. For inaccessible tree s on neighboring properties , t ags were
affixed to wood fences adjacent to their respective tree trunks.
• Provide measures to help avoid or mitigate impacts to retained or removed trees.
• Prepare a written report containing the above information, and submit via email as a
PDF document.
18151 Over look Road, Los Gatos Page 1 of13
Town of Los Gatos Community De velopment Department
Da vid L. Babby, Registered Consu lting Arborist® S eptember 21 , 2015
2.0 TREE COUNT AND COMPOSITION
Fifteen (15) trees of eight various species were inventoried for this report. They are
sequentially numbered as #1 thru 15, and the table below identifies their names, assigned
numbers, counts and percentages.
%OF
NAME TREE NUMBER(S) COUNT TOTAL
Coast live oak 6, 7, 11 , 14 4 27 %
Deodar cedar 1 1 7%
European beech 4 1 7%
Evergreen pear 5 1 7%
Glossy privet 9, 10 , 13 3 20%
Monterey pine 2,8, 12 3 20%
Pacific wax myrtle 3 1 7%
Western redbud 3 1 7 %
Total 15 100%
As illustrated in the above table, the tree landscape on and surrounding the si te is
populated predominantly by coast live oak, privet and Monterey pine .
Specific information regarding each tree is presented within the table in Exhibit A. The
trees' corresponding numbers and approximate locations can be v iewed on the site map in
Exhibit B , and photographs are presented in Exhibit C.
Tree #3 , a small redbud, is situated within the public right-of-way along Overlook Road
and is regarded as a street tree.
18151 Overlook Road, Lo s Gatos Page 2 of13
Town of L os Gatos Community Development Department
David L. Babby, Registered Consulting Arborist® September 21, 2015
Nine (9) trees have trunks originating on neighboring properties, and were inventoried
due to their proximity to the project site ; they include #1, 4, 6-10, 12 and 13.
Of the I 5 inventoried trees , the following 12 are regulated and defined as protected
trees: 1 #1-8, 11, 12, 14 and 15.
The other three trees, #9, 10 and 13, are exempt from regulation, pursuant to Section
29.10.0970 of the Town Code, due to being privets with trunk diameters Jess than 24
inches (all are situated on neighboring properties).
Ten (10) trees were not shown on the prior plans reviewed , and their locations shown on
the map in Exhibit B are only roughly approximate and should not be construed as being
surveyed ; they include #1, 4, 6-10, 12, 13 and 15 (accounts for all those on neighboring
properties plus #15).
Other trees located throughout the site were not inventoried due to having trunks with
diameters less than four inches.
1 Pursuant to Section 29.10.0960 of the Town 's Municipal Code, a "protected tree" has a trunk with a
diameter 2::4" at three feet above grade. Fruit-or nut-bearing trees with trunk diameters le ss than 18" are
exempt (Section 29.1 0.0970).
18 15 1 Overlook Road, Los Gato s Page 3 of13
Town of Los Gatos Community Development D epartm ent
Da vid L. Babby, Registered Consulting Arboris t® September 21, 2015
3.0 SUITABILITY FOR TREE PRESERVATION
Each tree has been assigned either a "high," "moderate" or "low" suitability for
preservation rating as a means to cumulatively measure its existing health, structural
integrity, anticipated life span, location, size, particular species, tolerance to construction
impacts , growing space, and safety to property and persons within striking distance.
Descriptions of these ratings are presented below; the high category is comprised of no
trees, the moderate category six (or 40%), and the low category nine (or 60%).
High: Applies to none.
These trees appear relatively healthy and structurally stable; have no apparent, significant
health issues or structural defects; present a good potential for contributing long-term to the
site; and require only periodic or regular care and monitoring to maintain their longevity
and structural integrity. They are typically the most suitable for retaining and incorporating
into the future landscape.
Moderate: Applies to trees #1, 4, 6, 8, 11 and 14.
These trees contribute to the site, but at levels less than those assigned a good suitability;
may have health and/or structural issues that can potentially be reasonably addressed and
properly mitigated; and frequent care is typically required for their remaining lifespan.
They might be worth retaining , if provided proper care, but not seemingly at significant
expense or major design revisions.
low: Applies to trees #2, 3, 5, 7, 9, 10, 12, 13 and 15.
These trees have serious or significantly weakened health and /or structural defects that are
expected to worsen regardless of tree care measures employed (i.e. beyond likely
recovery). Removal of those located within the site is recommended to improve the tree
landscape and/or site safety.
18151 Overlook Road, Los Gatos Page 4 of13
Town of Los Gatos Community Development D epartm ent
Da vid L. Babby, R egistered Consulting Arborist® September 21,2015
4.0 REVIEW OF POTENTIAL IMPACTS
Based on my review of project plans, in conjunction with a specific tree's condition and
tolerance to impacts, the following disposition is anticipated:
• Removals (four in total): #2, 3, 5 and 15.
• Retained (eleven in total): #1, 4 and 6-14 .
Regarding removals , tree #2 is a Monterey pine intolerant of root loss , and its decline and
ultimate demise is anticipated within one or more years following site development. Tree
#3 is a small redbud with poor structure, and excavation for constructing the new driveway
will extend up to its trunk and result in severe impacts . Tree #5 is a small evergreen pear
also with a poor structure . Tree #15 can be considered a tall shrub, and is anticipated to be
removed during excavation for the basement.
To my understanding, an application has been submitted to the Town regarding removing
tree #11 , the rearmost oak on the property ; specific reasons for removal are unrelated to
future site construction.
Tree #4 is specified for retention , but would sustain substantial root impacts during
construction of the proposed future curb and parking space/driveway within the existing
planter and six inches from existing fence; when considering overexcavation is needed to
form and pour the curb/parking space, ground disturbance will occur up to the fence .
Based on #4's size, its protection zone should be a minimum of eight feet from the trunk's
base to back of rock wall (i .e . where dirt of the planter and rocks meet), where all
overexcavation, compaction, trenching and other ground disturbance should be avoided.
Tree #4's base of trunk is roughly four feet from the fence, and the existing planter is 18
inches wide between the fence to back of rock wall (the planter is anticipated to contain
significant roots). When considering this information, design revisions are needed for
adhering to the TPZ and achieving a reasonable assurance of #4's survival.
18 151 Ove rlook Road, Los Gatos Page 5 of 13
Town of L os Gatos Community D evelopment Depar tm ent
David L. Babby, Registered Consulting Arborist® September 21 , 2015
5.0 TREE PROTECTION MEASURES
This section presents recommendations for achieving the protection of retained trees
throughout construction. They should be carefully followed, are subject to revision upon
reviewing revised or additional project plans, and I should be consulted .in the event any
measure cannot be feasibly implemented. Please note all referenced distances from trunks
are intended to be from the closest edge (face of) of their outermost perimeter at soil grade.
5.1 Design Guidelines
I. Designate a Tree Protection Zone (TPZ) to be the section of existing unpaved
ground beneath or beyond a tree's entire canopy; for #4, it should be as specified in
Section 4.0 of this report , and for #6, a minimum distance of nine feet west of its
trunk, and from this point north and south, up to 15 feet from the trunk .
A TPZ is where the following activities shall be avoided: trenching , soil scraping,
compaction, mass grading , finish-grading , overexcavation , subexcavation, tilling ,
ripping , swales, bioswales , storm drains, dissipaters, dry equipment cleaning,
stockpiling and dumping of materials, equipment/vehicle operation, and shoring
piers/excavation. In the event an impact encroaches slightly within a setback, it can
be reviewed on a case-by-case basi s to dete rmine whether measures can sufficiently
mitigate the impacts to less-than-significant level s.
2. Where beneath the canopies of trees #6 and 14, limit overexcavation, compaction ,
trenching and other soil disturbance to within 12 to 24 inches beyond the first floor
foundation. For tree #4 , the same limitations are needed beyond the basement and
lightwell walls, as well as the first floor foundation.
3. If shoring is used for constructing the basement, the layo ut should not r equire the
loss or large limb s o r branches during operation of a pile driver or drill ri g for
shoring (and soil nailing and shotcrete utilized should a conflict exist).
4 . For tree #4, implement the design recommendations provided in Section 4.0.
18151 Ove rlook Road, Los Gatos Page 6 of13
Tow n of Los Gatos Community D e velopm ent Departm ent
Da vid L. Babby, Registered Con sulting Arborist® September 21, 2015
5. The proposed retaining wall adjacent to tree #6 shall require no excavation,
trenching or compaction within its TPZ (e.g. utilize a drystack wall with no footings).
Should footings be required for the desired wood wall , the post locations shall be
installed as discussed in Section 5 .3 of this report.
6. The permanent and temporary drainage design, including downspouts, should not
require water being discharged towards a tree's trunk.
7. The assigned numbers should be added to Sheet 3 (excluding exempt trees #9 , I 0
and 13). Additionally, #4's location should be updated on Sheets A I and 3 to reflect
what is identified in Exhibit A.
8 . Update Sheets AI , AJ.I and C3 to illustrate protection fencing as shown in red on
the map in Exhibit B. Other fencing locations can be omitted from the plans.
9. On the demolition plan, specify that all below ground existing and unused pipes,
vaults and lighting shall be abandoned and cut off at existing soil grade where
within a TPZ (rather than being dug up and causing root damage).
10. Swales should be established well-beyond tree canopies. Where necessary within ,
they should be as far from the trunks as possible, require no more than a two-to
three-inch deep cut or fill , avoid severing roots 2:two inches in diameter, and not be
compacted (foot-tamping is acceptable).
11 . The erosion control design should consider that any straw wattle or fiber rolls
require a maximum vertical soil cut of two inches for their embedment, and are
established as close to canopy edges as possible (and not against a tree trunk).
12. Per Section 29.10.1000(C.l) of the Ordinance, a copy of this report (or updated one)
must be incorporated into the final set of project plans ; titled Sheets T-1, T-2, etc.
("Tree Protection Instructions"); and referenced on all site-related project plans.
18 151 Overlook Road, Los Gatos Pa ge 7 of13
Town of Los Gatos Community D evelopment Department
David L. Babby, R egistered Consulting Arborist® September 21 , 2015
13. The landscape design should conform to the following additional guidelines:
a. Plant material installed beneath the canopies of the oaks should be drought-
tolerant, limited in amount, and planted at least five or more feet from their
trunks. Plant material installed beneath the canopies of all other trees should be
at least 24 to 36 inches from their trunks.
b. Irrigation beneath the oak canopies should not be applied within a distance of
five times their trunk diameters. Irrigation for new plant material beneath their
canopies should be low-vo lume, applied irregularly (such as only o nce or twice
per week), and temporary (such as no more than three years).
c. Irrigation and lighting features (e.g. main line, lateral lines, valve boxes,
wiring and controllers) should be established beyond TPZs . In the event thi s is
not feasible , they may require being installed in a radial direction to a tree's
trunk, and terminate a specific distance from a trunk (versus crossing past it).
d . Ground cover should be comprised (partially or entirely) of a three-to four-
inch depth of coarse wood chips or other high-quality mulch (gorilla hair, bark
or rock, stone, cobble, gravel , black plastic or other synthetic ground cover
should be avoided). Mulch should remain six inches from the tree s ' trunks.
e. Tilling, ripping and compaction within TPZs should be avoided.
f. Bender board or other edging material proposed beneath the canopies should be
established on top of existing so il grade (such as by us ing vertical stakes).
14 . Mitigation is necessary to compensate for the removal of protected trees, and
Section 29.10.0985 can be used as the framework for determining amounts and s izes .
The trees shall be planted prior to final inspection, double-staked with rubber tree ties
(may not be necessary for trees of 36-inch box size and larger), and all forms of
irrigation be of an automatic drip or soaker hose system placed o n the soil surface
and not in a sleeve. Additionally, to achieve the greatest assurance of proper
installation, all new trees shall be in stalled, including necessary irrigation , by an
experienced California State-licensed landscape contractor or tree-service company.
18151 Overlook Road, Los Gatos Page 8 of 13
Town of Los Gatos Community De velopm ent Department
David L. Babby, R egistered Consulting Arborist® September 2 1, 2015
5.2 Before Demolition, Grading and Construction
I 5. Manually restore the soil grade at the rear of the site ; the ground should be
'smoothed' and leveled out, being careful not to excavate soi l and roots .
16 . Spread a four-to five-inch layer of coarse wood chips (Yt-to %-inch in size) from a
tree-service company over the ground within the property's rear section .
17 . A root zone buffer, for foot-traffic only, should be established for tree #6 between
protecti on fencing and first-floor foundation. It shall comprise a six-to eight-inch
layer of coarse wood chips manually spread on unpaved ground , and to create a
sturdy walking surface, can be covered by plywood sheets of at lea st %-inch thick
and secured together.
18 . The root collars of trees #11 and 14 must be fully cleared of rock and soil o n all
sides (360°), and the work perfo rmed by a professional and state-licensed tree service
ei ther through hand-digging or the us e of an Airspade (not applicable for #II if its
remova l is authorized by the Town).
19. Establish tree protection fencing to restrict access into TPZs, and where along
future foundations , no farther than five feet from the basement wall and /or first-floor
foundation ; locations are identified on the map in Exhibit B. This fencing shall
remain throughout construction, and co nsist of five-to six-foot high chain link
mounted on eight-foot tall , two-inch diameter galvanized steel posts th at are driven
into the ground.
20. Pursuant to Section 29.10.1005(a)(4) of the Town Code, 8.5-by 11-inch warning
signs shall be affixed and prominently displayed on each side of fencing oppos ite the
trees ' trunks: "WARNING -Tree Protection Zone -this fence shall not be removed
and is subject to penalty according to Town Code 29 .10 .1 025 ." The se signs should
be intact pri or to commencing demolit ion.
18 151 Overlook R oad, Los Gatos Page 9ofl3
Town of Los Gatos Co mmunity Developm ent Departm en t
David L. Babby, Registered Consulting Arborist® September 21 , 2015
5.3 During Demolition, Grading and Construction
21 . Supply water to the root zone s of #4, 6 a n d 14 every three to fo u r weeks throughout
the entire construction process, at an a mount of five to ten gallons per inch of trunk
diameter. Various application meth ods include either floodin g the in side of a 12-inch
tall berm formed around or near a canopy's perimeter, using soaker ho ses, or thro ugh
deep-root injection. For #4 and 6, watering only on the proj ect site is sufficient.
22. A root zone buffer, for foot-traffic only , s hould be established for #4 imm ediately
following rem oval of the rear patio . It should be established between protection
fe ncing and the baseme nt/li g htwe ll wall, and comprise a s ix -to e ight-inch layer of
coarse wood chips manually spread o n unpaved ground; to create a sturd y wa lkin g
surface , the chips can be covered by plywood sheets of at lea st %-inch thi ck and
secured together.
23 . Avoid us ing tree trunks as winch supports for moving or lifting heavy loads.
24 . The staging area and route(s) of access s ho uld b e established beyond TPZs .
25. Excavation for section of driv e (parking space locatio n) beneath #4's canopy should
first be perfo rmed by a one-foot wide trench being manually dug along the
perimeter of where soi l excavation will occur c losest to the t re e's trunk, and down to
t he required subgrade de pth (to avoid roots breaking and be in g damaged closer to the
trunk than otherwise ne eded). Roo t s encountered with diameters of ~two inch es shall
be clean ly severed by ha nd (at 90° to the direction of root growth) agai nst the tree
side of the trench. All soil beyond the trench (i.e. away from the tre e) can then be
mechanically excavated usin g heavy equipment, and remaining o utsi de t he fence d
area(s). Alternatively, the use of a stu mp grinder could be uti li zed precisely where a
curb/gutter and any overcut (12" max) will be established.
26. Any approved digging or trenching within a T PZ shall be manually performed
without the use of heavy equipment or tractors operating o n unpaved ground beneath
canoptes.
18151 Overlook R oad, Los Gatos Page 10 ofl3
Town of Los Gatos Community Development Department
David L. Babby, R egis ter ed Consulting Arborist® September 21 , 2015
27. Avoi d damaging or cutting roots with diameters 2:two inches. Should roots of this
size be encountered , w ithi n one hour of exposure, they should either be covered by
burlap that remain s continually moi st until covered by so il. If they are approved for
c uttin g, c leanl y severe at 90 ° t o the angle of root growth against the cut line (using
to ppers or a sharp hand saw), and then immediately after, the cut end either buri ed
with soil or covered by a plastic sandwich ba g (and secured us in g a rubber band, and
re moved just before backfilling).
28. Tree pruning s hall on ly be performed in accordance with ANSI A300-200 I
standards, by a California licensed tree-service contractor (D-49) that has an ISA
certified arborist in a supervisory r ole, carries General Liability and Worker's
Compensation in s urance, and abides by ANSI Z l 33.1-2006 (Safety Operations).
29. Re mov ing existing hardscape and home within and ne ar a TPZ, s uch as for tree
#14 , mu st be carefully pe rformed to avoid excavating roots and soil during the
process (and above-ground portion of a tree). The section of existing hardscape
within the desig ned-fenced area for# 14 s h ou ld be manually performed.
30. The root zone buffer for tree #14 shall be installed immediately following
demolition of the existing rear patio (completed prior to ba sement excavation).
3 1. Any fence posts to be established within a TPZ must be carefully designe d to avoid
potential signifi cant impa cts. In doing so , I recommend they are planned to be at
lea st two to three feet from a trunk , minimized in diameter, and spaced as far a part as
po ss ible (e.g. at least five plus feet apart). The des ign sho uld specify that th e post
ho le s are manuall y du g us in g a post ho le digger or shovel , and roots two inches and
greater in diameter retained and protect ed during the process (i n the event a root of
this s ize is encountered during di gging , the ho le s ho uld be shifted over 12 inches and
the process repeated).
32 . Spoils created during digging shall not be piled or spre ad on unp aved gro und w ithin
a TPZ. If essential , spo il s ca n be temporarily piled on plywood or a tarp.
18 151 Overlook R oad, Los Gatos Page 11 of 13
Town of Los Ga tos Community Development Department
David L. Babby, Registered Consulting Arboris t® September 21 , 2015
33. Dust accumulating on trunks and canopies during dry weather periods should be
periodically washed away (e.g. every two to three months).
34. Avoid disposing harmful products (such as cement, paint, chemicals, oil and
gasoline) beneath canopies or anywhere on site that allows drainage within or near
TPZs . Herbicides should not be used with a TPZ; where used on site, they should be
labeled for safe use near trees. Liming shall not occur within 50 feet from a trunk.
35. Great care must be taken by equipment operators to position their equipment to
avoid the trunks and branches of trees , including the scorching of foliage (including
along the road).
36. Fertilization may benefit the trees' health , vtgor and appearance. If applied,
however, soil samples should first be obtained to id e ntify the pH levels and nutrient
levels so a proper fertilization program can be establis hed . I further recommend any
fertili zation is performe d under the direction and supervision of a certified arborist,
and in accordance with ANSI A300 (Part 2)-2004 Fertiliz ation standards.
18 151 Overlook Road, L os Gatos Page 12 of 13
Town of L os Gatos Community Development Dep artment
David L. Babby, Registered Consulting Arborist® September 21 , 2015
EXHIBIT A:
TREE INVENTORY TABLE
(three sheets)
18151 Overlook Road, Los Gatos
Town of Los Gatos Community D e velopment Department
David L. Babby, R egis tered Consulting Arborist® September 21, 2015
EXHIBIT 8:
SITE MAP
(o ne sheet)
18 151 Overlook R oad, Los Gatos
Town of Los Gatos Co mmunity D evelopment Department
David L. B obby, R egistered Consulting Arborist® September 21 , 2015
EXHIBIT C:
PHOTOGRAPHS
(four sheets)
Phot o Index
Page C-1: Trees #1 thru 6 Page C-3: Trees #10 thru 13
Page C-2 : Trees #6 thru 9 Page C-4: Trees #14 and 15
18151 Overlook Road, Los Gatos
Town of Los Gatos Community Development D epa rtment