HomeMy WebLinkAboutITEM II - PUBLIC WORKS - DESIGN STANDARDS
Chapter 12.36
STREET TREES
Sections:
12.36.0 I OShort title.
12.36.020Enforcement officer.
12.36.030Planting or removal- Permission required.
12.36.040Prohibited trees.
12.36.050Nuisances - Designated.
12.36.060Nuisances - Abatement - Required.
12.36.070Nuisances - Abatement - Notice.
12.36.080Nuisances - Abatement - By city - Costs recovery.
12.36.090Abuse or mutilation of trees prohibited.
12.36.1 OOViolation - Penalty.
12.36.11 ORemedies not exclusive.
12.36.010Short title.
12.36.020Enforcement officer.
The city engineer or his duly authorized representative shall be charged with the
enforcement of this chapter. (1957 code S 8.15.020.)
12.36.030Planting or removal- Permission required.
No trees or shrubs shall be planted in or removed from any public parking strip or other
public place in the city without permission from the city engineer. Plantings for which
permission has been granted shall be in accordance with the city of Auburn design and
construction standards. (Ord. 5145 S 1, 1998; 1957 code S 8.15.030.)
12.36.040Prohibited trees.
It is unlawful to plant in any public parking strip the following trees: Poplar, willow,
cottonwood, fruit trees (except ornamental types), nut trees, ailanthus, mountain ash and
Oregon or big-leaf maple, or any other tree the roots of which cause injury to the sewers,
sidewalks or pavements, or which breed disease dangerous to other trees or to the public
health. No tree shall be planted within two feet of any sidewalk or pavement unless the
planting is accomplished in accordance with a comprehensive street tree planting
program approved by the city for the subject street. Poplar, willow, American elm or
cottonwood trees planted anywhere in the city must be placed at least 100 feet away from
public sewers. (1957 code S 8.15.050.)
12.36.050Nuisances - Designated.
Trees, shrubs or vegetation or parts thereof which so overhang any sidewalk or street or
which are growing thereon in such manner as to obstruct or impair the free and full use of
the sidewalk or street by the public are public nuisances. Grass, weeds, shrubs, bushes,
trees or vegetation growing or which has grown and died upon any property and which is
a fire hazard or a menace to public health, safety or welfare are likewise public nuisances.
It is the duty of the owner of the property wherein or whereon any such nuisances exist to
abate the nuisances by destroying, removing or trimming the growth. (1957 code S
8.15.040.)
12.36.060Nuisances - Abatement - Required.
The city engineer shall enforce this chapter, and if any property owner fails or refuses to
abate any such nuisance as contemplated by ACC 12.36.050, the city council may, after
report filed by the city engineer, by resolution require such property owner, in addition or
alternative to the penalties prescribed by ACC 12.36.100, to abate the nuisance by
removal or destruction, at his cost and expense, within a time specified in the resolution;
and if the removal or destruction is not made by such owner within the time specified, the
city engineer may abate the same as provided in ACC 12.36.080. (1957 code S 8.15.060.)
12.36.070Nuisances - Abatement - Notice.
The resolution mentioned in ACC 12.36.060 shall not be passed until the property owner
is given at least five days' notice ofthe pendency of the proposed resolution. Such notice
shall be given by the city engineer's mailing a copy of the notice to the owner as shown
upon the records of the county treasurer and at the address shown thereon; and if no
owner and address is shown on such records, a copy of the notice shall be posted upon
the property, and shall also be published in one issue of the official newspaper. The
mailing, posting and publication shall be made at least five days before the resolution is
adopted and proof shall be made by affidavit of the city engineer filed with the city clerk.
The notice shall include the resolution number and both shall describe the property
involved and the nature of the hazardous condition constituting the nuisance. (1957 code
S 8.15.070.)
12.36.080Nuisances - Abatement - By city - Costs recovery.
If the nuisance is not abated by removal or destruction by the property owner within the
time fixed in the resolution, the city engineer may abate the same and he shall render a
bill covering the cost of such abatement, including the engineer's expense, and mail the
bill to the property owner. 1f the property owner fails or refuses to pay the bill
immediately, or ifno bill is rendered because he cannot be found, the city engineer, in the
name of the city, may file a lien therefor against the property, which lien shall be in the
same form, filed with the same officer and within the same time and manner and enforced
and foreclosed as is provided by law for liens for labor and material. (1957 code S
8.15.090.)
12.36.090Abuse or mutilation of trees prohibited.
Except to abate a nuisance as defined in this chapter, it is a violation of this chapter to
damage, destroy or mutilate any tree, shrub or plant in a public parking strip or any other
public place, or to attach or place any rope or wire (other than one used to support a
young or broken tree), sign, poster, handbill or other thing to or on any tree growing in a
public place, or to cause or to permit any wire charged with electricity to come in contact
with any such tree, or to allow any gaseous, liquid or solid substance which is harmful to
such trees to come in contact with their roots or leaves; provided, however, that nothing
contained in this section shall preclude either the owner or occupant of real property from
trimming or removing trees, shrubs and plants in the parking strip of such real property.
(1957 code S 8.15.080.)
12.36.100Violation - Penalty.
Any violation of this chapter shall be enforced pursuant to the provisions of Chapter 1.25
ACC. (Ord. 4502 S 6,1991; 1957 code S 8.15.100.)
12.36.110Remedies not exclusive.
The remedies prescribed in this chapter are in addition to all other remedies provided or
authorized by law. (1957 code S 8.15.120.)
10.08.1 General Landscaping Requirements
An area devoted to landscaping is included within the right-of-way of all street
classifications. This landscape strip is an integral part of the roadway cross-section. It
serves several important functions, including improving pedestrian safety by providing a
buffer between traffic and the sidewalk; providing the perception of a narrower travel
corridor, thereby slowing traffic; improving air quality; and improving the aesthetic
appearance of the street.
The developer shall design and install the landscape strip in accordance with these design
standards. The proposed design shall be reviewed and approved by the City.
The size of the landscape strip has a vital effect on the health and survival of the plants.
Trees in particular need a large area of ground surface around them to provide sufficient
space to collect the nutrients and moisture they need to thrive. For this reason, when
conditions allow for a larger than standard landscape strip, it is strongly encouraged that
one be provided.
The minimum width required for landscape strips is five feet (5'). Landscape strips shall be
located between the back of the curb and the sidewalk except for on Local Residential
streets where on one side of the street the landscape strip shall be behind the sidewalk.
The Developer shall provide for and plant street trees in accordance with these design
standards.
If the available right-of way does not provide enough space of a five-foot (5') landscape
strip and dedication of additional right-of-way is not possible, the width of the sidewalk shall
be increased to seven feet (7') and the landscape strip placed behind the sidewalk and
incorporated into the adjoining site landscaping.
10.08.2 Landscape Strip Components
Landscape strips contain several components. These include soil, the plants themselves,
structural items such as root barriers and tree grates, and may include street furnishings
such as luminaries, traffic signs, bus stops or shelters, benches, and mail boxes.
10.08.3 Landscape Strip Dimensions
The roadway sections designate either five-foot (5') or five-and-a-half-foot (5%') wide
landscape strips.
10.08.4 Plant Layers
It is recommended that a multi-layer planting be used in the landscape strip. For instance,
grass or a ground cover should be used at the ground level, low-growing shrubs may
comprise the next layer, and trees form the upper or canopy level. Within this general
framework are many choices, outlined in the Plant Selection section below.
In summary, the landscape strip will contain the following layers:
1. Ground Cover(s) or Grass-Required
2. Shrubs with a mature height of three feet (3') or less-Optional
3. Trees-Required
10.08.5 Trees
10.08.5.1 Placement and Spacing
Trees shall be placed so that they do not obstruct the view of any street intersection,
driveway, or visibility of any traffic control device or sign. Sight distance triangles shall
be used to analyze visibility at street intersections. Trees shall be centered in the
planting strip.
Trees will be spaced as follows, except where special site conditions require variation
for safety or other reasons:
Tree Size Height Recommended Spacing Landscape
Strip Widths
Small To 25 Feet 15 - 20 Feet Aoart 5 Feet
Medium 25 - 50 Feet 20 - 30 Feet Apart 5.5 - 8 Feet
Larae 50 - 70 Feet 30 - 50 Feet Aoart 8-12Feet
Very Lar>/e 70 Feet + 50 Feet or Greater 12 Feet +
Nearby features such as buildings or overhead wires will also affect where trees should
be located. Minimum size for street trees shall be a two-inch (2") caliper, measured two
feet (2') above the root ball.
Planting Next to a Building: Where a building is placed close to the sidewalk, the
mature size of a tree should be considered when selecting species. Trees with a
pyramidal, columnar, or oval shaped canopy are preferable; a tree with a round head is
generally unsuitable in this situation.
Overhead Wires: When trees must be planted under utility lines, species with a
maximum height of twenty-five feet (25') should be selected.
Street Lighting: Trees should generally be at least twenty feet (20') from light
standards. Planting locations should be coordinated with locations of lighting standards.
Clearance: Trees shall be pruned as they grow to provide at least seven feet (7')
vertical clearance above sidewalks and fourteen feet (14') of vertical clearance above
roadway surfaces.
10.08.5.2 Tree Canopy Shape
Tree canopy shapes are an important factor in the selection of street trees. The setting
will often dictate which canopy shapes are most appropriate. This in turn will aid in the
selection of the most suitable species.
The guidance offered below includes information about which tree canopy shapes work
best under different conditions. Table 10-4 offers information about tree species and
their canopy shapes.
10.08.5.2.1 V-Shaped Trees
V-shaped (sometimes also called "vase shaped") trees have canopies that are
narrow toward the bottom and broad at the top. The American Elm is a classic
street tree with this shape. V-shaped trees may have arching branches that form a
canopy over both street and sidewalk. They generally do not cause problems with
overhead power lines or traffic.
10.08.5.2.2 Pyramidal Trees
Pyramidal or cone-shaped trees are typically broad at the base of the canopy and
are somewhat pointed at the top. European Beech is one tree that becomes
pyramidal with age. Planted close together, pyramidal trees can screen unwanted
views or create vistas. Lower branches sometimes droop with age and may have to
be limbed up in later years to provide the needed clearance.
10.08.5.2.3 Round Trees
These are generally wide spreading trees that need more space than other shapes.
The Red Sunset Maple is one example of a round tree.
10.08.5.2.4 Oval Trees
An oval tree is a good choice around buildings and adjacent to traffic. Oval trees,
like the Raywood Ash, are taller than they are wide and cause little interference with
traffic
10.08.5.2.5 Columnar Trees
Columnar trees are useful in locations where there is little available room between
the street and buildings, awnings, or other features. Branches of columnar trees
tend to grow up rather than out. Many branch lower than other types of trees
without causing problems with traffic or pedestrians.
10.08.5.3 Root Direction Devices
All street trees planted within a five-foot (5') wide landscape strip shall use a root
direction device to deflect tree roots downward into the soil. These devices are used to
eliminate damage to sidewalks as the tree roots extend beyond the original planting pit.
The root barrier should be placed along two sides of the tree, parallel to the sidewalk
and to the curb line. Under specific circumstances, wider strips that contain utilities
may also need root barriers to reduce conflicts. Plan submissions should indicate the
location of root barriers and provide a specification sheet on the product to be used.
10.08.5.4 Tree Planting Wells and Grates
In highly urbanized settings such as downtown, it may be necessary to install street
trees into an existing street and sidewalk setting. Where high levels of pedestrian traffic
is expected, it may be necessary to place trees into a paved area rather than a
landscape strip. In these situations planting wells and grates may be necessary. The
desirable size for a tree planting well is thirty-six square feet (36 sq.ft.) or greater. A
minimum of twenty-five square feet (25 sq. ft.) should be provided.
Where trees are within a heavily traveled pedestrian area, their roots can be easily
damaged. In these areas tree grates or other means such as pavers in sand will be
required to protect the health of the tree.
Where tree wells or grates are necessary, provide planting details, specifications, and
product sheets for proposed tree-planting wells and tree grates. See Standard Details
TRAFFIC-14 and TRAFFIC-15.
10.08.6 Plant Selection
There are innumerable plant choices for each layer of the landscape strip. Selection is
based on:
. Size of the landscape strip
. Canopy shape of trees
. Size and type of leaves
. Root shape
. Site environmental conditions, such as the amount of sunlight available or
moisture in the soil; and
. Aesthetic qualities desired.
Needled evergreens, such as firs or spruces, shall NOT be used in landscape strips,
unless the strips are very wide. Broad-leaved evergreens such as magnolias are
acceptable.
10.08.7 Plant Selection Table
Table 10-5 provides several acceptable species of ground covers, shrubs less than 3 feet
high, and a variety of flowering or standard street trees. Many other plants are appropriate;
alternative selections may be proposed if desired. Alternative plant choices will be
evaluated and approved by the City.
Column Headings: A short description of severai of the column headings follows:
Size:
Small
Medium
Large
Sun:
Sun Needs full sun
Sun/Shade Takes sun to part shade; needs at least Y, day of sun
Shade Shade to part shade. Protect from full sun, especially in afternoon
H20 Req. (Requirement):
Low Drought tolerant after 1 st year
Mod Moderate water need. May need supplemental watering during dry season.
High Requires irrigation
Canopy Shape:
"v" V-shaped Trees (sometimes also called "vase shaped trees")
Pyramid Pyramidal trees or cone shaped trees
Round Round trees
Oval Oval trees
Col. Columnar trees
To 25 Feet
25 to 50 Feet
50 to 70 Feet
TABLE 10.5 (TREES)
Min.
Botanical Common Size Sun H2O Landscape Canopy Remarks
Name Name Req. Strip Shape
Width
Hedge Small! Sun! Tough urban plant. Any well-drained
Acer campestre Mod 5-8 Feet Round. soil. Yellow fall color. Broad crown. May
Maple Med Shade need to be limbed un when \/ounn
Acer ginnala Sun! Spectacular scarlet fall color. Fast
Amur Maple Small Low 5-8 Feet "v" growing. Tolerant of many soils,
Shade oOllution,saltanddrouoht
Acer plata no ides Large 8-12 Feet Oval Very adaptable to soil and climate
'Armstrong' Norway Med Sun Mod 5.8 Feet Col. condition. Difficult to grow grass under
'Columnare' Maple Med 5-8 Feet Round. Many cultivars wlvarying heights &
'Schwedleri' Laree 8-12 Feel Oval shapes
Acer rubrum
'Red Sunset' Med! Very adaptable: will grow in swamps or
'Oct. Glory' Red Maple Large Sun Mod 5-8 Feel Oval on rocky slopes. Needs shade over rool
area when used 85 a street tree
Others available
Carpinus betulus European SmalV Sun! Mod 5.8 Feet Col. Elegant appearance: needs no pruning
'Columaris' Hornbeam Med Shade Pesl&diseasefree.
Beautiful tree wldelicate texiura, red
Cercidyphyllum Katsura tinged leaves, good fall color. Shape
Med Sun Mod 5.8 Feet Round varies; can be multi-stemmed.
japonicum Tree TransplantB&B, early spring Rich,
moist, well-drained soil
Cercis Eastern Sunl Reddish purple flO'Wers, early spring
canadensis Redbud Small Shade Mod 5-8 Feet Round. Spreading habit w/flat top. Transplants
best when small Effective in clusters
Fraxinus Golden Small, narrow leaves give a tidy, fern-
oxycarpa Desert Ash Med Sun Mod 5-8 Feet Oval like appearance. Gold twigs, attractive
'Golden Desert' in winter. Red to purple fall color
Co!. to Distinctive fan-shaped leaL Light green
Ginkgo biloba Ginkgo Large Sun Mod 5-8 Feet foliage in spring; bright yellow in fall
Oval Plant male trees only Slow growing
Tolerates wide vari~tv of soil conditi~ns
Liquidambar CO!. to Dense canopy of 5-1obed, slar shaped
Sweetgum Large Sun Mod 5-8 Feet leaves. Yellow to red fall color Pointed,
styraciflua Oval wood':; frUit can be a nuisance
Callery Dark green glossy leaves in summer,
scarlet in fall. Heavy clusters of white
Pyrus calleryana Pear Med Sun Low 5-8 Feet Pyramid flowers in spring. May need corrective
and varieties (Flowering to Oval pruning when young. Varie1ias
Pear) 'Aristocrat': 'Chanticll~~' ~R:~:Pire'
have a vanetv of cano she as
Easy \0 transplant Needs fertile, wall-
Large! drained soil. plenty of water. Tolerates
Quercus rubra Red Oak Very Sun High 8.12 Feet Round pollution. High branching and fairly
open shade make it a good choice for
Large big ~~v;:s and blvds. ~~;Ik r~~ or
oran efallcolor. Fasl rO'Wln
Formal look. Upright branching. Needs
Tilia cordata Littleleaf Sunl Ovall well-arained, fertile soil. Tolerant of
'Green spire' Liden Med Shade Mod 5.8 Feet Pyramid urban conditions. Easy to transplant.
Fragrant yellowish flowers In clusters in
June
Zelkova serrata Graceful vas9-shaped tree resembling
Zelkova Med Sun Mod 8.12 Feet 'V' the elm. Fair tolerance of soils, besl in
'Village Green' moist deep loam. Leaves light green in
sn-rinn, "ellowto russet in fail
TABLE 10-5 (GROUND COVER/LOW SHRUBSl
Min.
Botanical Common Size Spacing Sun. Landscape Flowers Remarks
Name Name Strip
Width
Arctostaphylos Kinnikinnick Sun! Usafulon slope, poor or dry
Small 5-8 Feet . soils, Slow to establish; must
una-ursi Bearberry Shade address earl" weed nroblems
C. dammeri Bearberry 3".6" Sun! 5-8 Feet . Fast growing, roolsfreely
Cotoneaster Shade
Hedera helix English Ivy Sun! Vigorous, should be wilhin a
6"-12' 12"-18" Shade 5.8 Feet comained area. Will climb
vertical surfaces
H. h. 'Ballica' Ballic Ivy 6"-12' 12"-18' Sun! 5.8 Feet Smallarlaafthan English Ivy: not
Shade as aggressive.
Tolerant of poor soils, soma
Hypericum St. Johns Sunf drought. Com pates well with
calycinum Wort to 12" 18" Shade 5-8 Feet . trees. Must be in confined space
or overtakes other plants. Showy
vellow nowers
Vinca minor Periwinkle 6" 12"-18" Shade 5-8 Feet . Needs regular watering
10.08.8 Planting Methods and Maintenance
Good horticultural practice should be employed in the preparation of the soil and planting
pits. This will include:
1. Conserving topsoil and replacing it on the site.
2. Performing soil tests.
3. Providing corrective soil preparation as necessary.
10.08.9 Establishment Period
The developer will be responsible for maintaining the trees and plants in the landscape
strip in a healthy condition for one (1) year after acceptance of the project. Because
landscape strips do not usually include irrigation, maintenance will include providing water
during dry periods. Weeds, diseases, and insect pests must also be controlled.
10.08.10 Deviations from the Landscape Strip Standards
Site conditions may occasionally make adhering to the landscape strip standards difficult.
Deviations from the standards may be requested. The following paragraphs list
circumstances that may be appropriate conditions for requesting a departure from the
design standards:
Root Direction Device: The root direction device may be omitted if the planting strip is
very wide or if the variety of tree to be planted is known to cause no sidewalk upheaval.
Grass or Ground Cover: Where it is extremely difficult to maintain grass or ground cover
in a landscape strip, heavy stone aggregate such as a washed river rock may be an
acceptable substitute. Lightweight rock such as lava rock is not acceptable. Paving over
the landscape strip will rarely be acceptable.
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LOCAL RESIDENllAL
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STANDARD DETAIL: TRAFFlC-32
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APPRO\IED BY CITY ENGINEER:
RESIDENTIAL COLLECTOR
ROADWAY SECTION
PUBLIC WORKS STANDARD DETAIL: TRAFFIC-29
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. DESIRABLE, MAY BE REDUCED TO 2.5 FT. MINIMUM.
CITY OF AUBU
MINOR AR1ERIAl
ROADWAY SECTION
PUBLIC WORKS STANDARD DETAil: TRAFFlC-28
APPROVED BY Cf1Y ENGINEER:
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CITY OF AUBUR
DATE:
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DEPT. OF PUBLIC
LOCAL NONRESIDENTIAL
ROADWAY SECTION
WORKS STANDARD DETAIL: TRAFflC-33
APPROVED BY CfTY ENGINEER:
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ROADWAY SECTION
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