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CHEYENNE URBAN FORESTRY
Tree Selection and Planting Guidelines
And
Tree Retention and Protection Guidelines
(For Construction Projects on City Lands)
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TABLE OF CONTENTS
PART 1 - Tree Selection
and Planting
SECTION 1 - General
1.01 Summary
1.02 Quality Assurance
1.03 Project Requirements
1.04 Material Submittals
1.05 Analyses of Samples and Tests
1.06 Construction Schedule
1.07 Inspection of Plant Material
1.08 Product Delivery, Storage, and Handling
1.09 Warranty and Replacements
SECTION 2 - Products
2.01 Plant Materials
2.02 Organic Soil Amendments
2.03 Commercial Fertilizers
2.04 Staking Material
2.05 Water
2.06 Mulching Material
2.07 Anti-desiccant
2.08 Tree Wrap
SECTION 3 - Execution
3.01 Layout and Excavation of Planting Areas
3.02 Planting Operations
3.03 Staking and Guying
3.04 Mulching
3.05 Cleanup
3.06 Maintenance
3.07 Winter Watering
3.08 Illustration
of Planting Containerized Trees and Shrubs (PDF
File)
3.09 Illustration of
Planting Balled & Burlapped (B&B) Trees (PDF
File)
END OF TREE SELECTION AND PLANTING SPECIFICATIONS
PART 2 - Tree Retention and
Protection
4.00 Tree Retention and Protection Plan
4.10 Reference Standards and Guidelines
4.20 Definitions
4.30 General Requirements
5.00 Demolition and Reconstruction Activities & Tree Protection
5.10 Demolition of Existing Concrete
5.20 Construction of Sidewalks, Curbs, Paving and Drainage Inlets
5.30 Irrigation or Utility Installation
5.40 Root Pruning
5.50 Tree Protection Fencing
5.60 Tree Protection Signs
6.00 Project Site Monitoring
7.00 Injuries to Existing Plants - Damage Penalties
8.00 Submittals
9.00 Tree and Other Plant Maintenance During and After Completion
of Construction
TREES
AND SHRUBS
PART
1 - TREE SELECTION AND PLANTING
SECTION 1 - General
1.01 SUMMARY
A. Work Included: Provide trees,
and planting of same if requested, complete as shown and as specified
including a one (1) year guarantee/warranty period if trees are
provided
and planted by the contractor.
1.02 QUALITY ASSURANCE, CITY
CODE, VEGETATION AND PLANTING STANDARDS
A. Certificates
1.
Submit certificates of inspection required by law for transportation
of each shipment of plants along with the invoice.
2.
File copies of certificates after acceptance of material. Inspection
by Governmental agencies at place of growth does not preclude
rejection of plants at the project site.
B. Applicable Standards: Apply standards
for plant materials as described in the following:
1.
"American
National Standard for Nursery Stock, ANSI Z60.1"
(off site link) most recent edition, American Association of Nurserymen,
Inc.
C. Applicable Standards: Apply
standards for tree and shrub fertilization as required in the
following:
1.
" American National Standard for Tree Care Operations - Tree,
Shrub, and Other Woody Plant Maintenance - Standard Practices
(Fertilization) ANSI A300 (Part 2) Fertilization",
most recent edition.
a.
Best Management Practices Tree and Shrub Fertilization, Companion
publication to to the ANSI A300 Standard for Tree, shrub, and
Other Woody Plant Maintenance -
Standard Practices (Fertilization)
D. City
of Cheyenne Road, Street & Site Planning Design Standards
(off site link) from the Cheyenne Metropolitan Planning Organization.
E. City
of Cheyenne Code: Title 17 Zoning; Title 12 Streets, Sidewalks,
and Public Places and Chapter 12.16 Trees and Shrubs.
(Off site link)
1.03 PROJECT REQUIREMENTS
A. Planting work shall be done under
the direct supervision of a qualified superintendent working on
the site with experienced laborers familiar with planting procedures.
B. Contractor shall be responsible
for obtaining any permits associated with planting in public rights-of-way
and/or storage of materials.
C. Existing Conditions:
1. Vehicular
accessibility on site shall be as directed by Director of Forestry
or project supervisor. Repair damage to prepared grounds and surfaces
caused by vehicular movement
during work under this section to original condition at no additional
cost to Owner.
1.04 MATERIAL SUBMITTALS
A. Samples: Submit samples, if required,
three (3) weeks prior to delivery to site. Attach product name,
address of manufacturer and/or supplier to each sample.
1.
Mulch: Wood - One (1) pint.
2.
Organic Soil Amendments: One (1) Pint of each type.
3.
Tree Strap: One (1).
4.
Fertilizer (as recommended from soil lab): Manufacturer's product
information, as well as receipts of purchase.
1.05 ANALYSES OF SAMPLES AND TESTS
A. Contractor, at their own cost,
will have project site soil tests done by a certified or qualified
soils testing lab to determine any fertilizer recommendations
prior to soil preparation
for planting trees and shrubs.
B. Sampling: Owner reserves right
to take and analyze samples of materials for conformity to specifications
at any time. Furnish samples upon request.
C. Rejected Materials: Contractor
shall remove rejected materials immediately from the site at their
own expense. Contractor shall pay cost of testing materials not
meeting
specifications.
1.06 CONSTRUCTION SCHEDULE
A. Contractor shall provide the
City Forestry Office of anticipated work schedule in writing or
by E-mail to Director and
Assistant Director
at least 14 days prior to start of landscape
work.
1.07 INSPECTION OF PLANT MATERIAL
A. Plants shall be subject to inspection
for conformity to specification requirements and approval by the
City at their place of growth prior to award of bid.
B. A written request for the inspection
of plant material shall be submitted to the City at least 10 working
days prior to planting. This request shall state the place of
growth and
the quantity of plants to be inspected.
C. Plants shall be inspected upon
delivery, and the City reserves the right to reject any plants
that do not meet the standards or that have been damaged during
shipment. Such
approval shall not impair the right of inspection and rejection
during progress of the work.
D. A Contractor's representative
shall be present at all inspections.
E. The City shall be the sole judge
of acceptability of nursery stock at any time during the course
of this contract.
1.08 PRODUCT DELIVERY, STORAGE, AND HANDLING
A. Labeling: Furnish standard products
in manufacturer's standard containers bearing original labels
legibly showing quantity, analyses, genus/species/variety/cultivar
and name
of manufacturer/grower. Labeling need not apply to collected material.
However, contractor shall warrant that plant material is true
to species specified.
B. Transportation: During transportation,
Contractor shall protect plant material from desiccation and all
other potential damage.
C. Storage: Store products with
protection from weather or other conditions which would damage
or impair the effectiveness of the product.
D. Handling: Do not lift or handle
container or balled and burlapped plants by tops, stems or trunks
at any time. Do not bind or handle plants with wire or rope at
any time.
E. Anti-Desiccant: At Contractor's
option, spray all evergreen or deciduous plant material in full
leaf with anti-desiccant just before transporting. Apply an adequate
film over trunks,
branches, twigs and foliage.
1.09 WARRANTY AND
REPLACEMENTS
A. Warranty: For a period of one
(1) year after Final Acceptance of all landscape work and at no
additional cost to the City, the Contractor shall replace any
plant material that
is dead, or that is, in the opinion of the City's Representative,
in unhealthy or unsightly condition, or that has lost its natural
shape due to dead branches or excessive pruning
of dead branches.
1.
Correct Species: Warrant that all plant materials are true to
species, variety and cultivar.
2.
Vigor: Warrant that all trees planted under this Contract shall
be healthy and in flourishing condition of active growth (in the
opinion of the City) one year from date of Final
Acceptance.
3.
Delays: All delays in completion of planting operations which
extend the planting into more than one planting season shall extend
the Warranty Period likewise.
4.
Condition of Plants: Plants shall be free of dead or dying branches
and branch tips, mechanical injury, and co-dominant stems. All
foliage shall be of normal density, size
and color. Plants shall be free of sunscald, disease and insect
infestations and shall have healthy buds. All plants shall be
symmetrical. All root-balls shall be properly
bound with burlap and wire baskets. Extremely dry or crushed root-balls
will be rejected. Trees shall be dug and transplanted in the same
growing season. Plant
materials exhibiting conditions which are determined unacceptable
due to poor health or poor installation by the Contractor shall
be repaired and/or replaced at no
additional cost to the City.
5.
Replacements: As soon as weather conditions permit, replace, without
cost to City, all dead plants and all plants not in a vigorous,
thriving condition, as determined by
City's Representative during and at the end of the Warranty Period.
Replacement materials shall be subject to the same inspection
process and all other requirements
of original material. Contractor shall closely match replacements
to adjacent specimens of the same species. Apply all requirements
of these specifications
to all replacements.
6.
Watering: Contractor shall be responsible for providing water
to the plants during the growing season and during the dormant
season as needed, while one-year Warranty
Period is in effect or when the city assumes responsibility of
the project.
a.
Contractor and City will agree upon a watering regime for plants
under City maintenance, but still under Contractor one-year warranty
and replacement period.
7.
Exclusions: Contractor shall not be held responsible for failures
due to neglect by City, vandalism, or vehicular damage during
Warranty Period. Report such conditions
to City's Representative.
SECTION
2 PRODUCTS
2.01 PLANT MATERIALS
A. General: Only plant material
with seed stock originating and suited for growth in United States
Department of Agriculture (USDA) hardiness zones 2, 3, & 4,
will be acceptable
for this project.
1.
Growing Conditions: Plants shall be nursery-grown in accordance
with good horticultural practices under climatic conditions similar
to those of project, USDA Zone 4b,
for at least two (2) years unless otherwise specifically authorized.
2.
Collected Plant Material: All plant material which, due to size
or quantity and cannot be nursery grown, may be collected. The
Contractor, and if possible, the Director of
Forestry or Representative will review this plant material in
its native state before collection as is reasonably practical.
The Director of Forestry or Representative reserves
the right to reject this same material once it reaches the site
if, in his/her opinion, it is not of the same quality as when
it was initially reviewed.
3.
Appearance: All plants shall be exceptionally heavy, symmetrical,
tightly knit, and so trained or favored in development and appearance
as to be superior in form for their
species, with regard to number of branches, compactness, and symmetry.
Trees which have multiple leaders, unless specified, or damaged
or crooked leaders, will
be rejected. Trees with abrasions of the bark, sunscald, disfiguring
knots, or improper pruning cuts shall be rejected.
4.
Vigor: Plants shall be sound, healthy and vigorous, well branched
and densely foliated when in leaf. They shall be free of disease
and insect pests. They shall have healthy,
well-developed root systems. Plants shall be free from physical
damage or adverse conditions which would prevent thriving growth.
5.
Plants shall be harvested and transplanted during the same growing
season.
B. Condition of Root System: The
root-balls of all trees must be completely free of circling or
girdling roots.
C. Measurements:
1.
Take a caliper (trunk diameter) measurement at a point on the
trunk six inches (6") above natural ground line for trees
up to four inches (4") in caliper and at a point
twelve (12") inches above the natural ground line for trees
over four inches (4") in caliper.
2. Substitutions:
Substituted plants shall be true to species and variety and shall
conform to measurements specified except that plants larger than
specified may be used
if accepted by City. Use of larger plants shall not increase the
contract price nor allow the Contractor to use smaller than specified
material on other plants. If larger
plants are approved, the most recent version of the American
Standard for Nursery Stock ANSI Z60.1 shall dictate the
size of the root-ball or container.
2.02 ORGANIC SOIL AMENDMENTS (Composted)
A. Contractor shall, at their own
expense, supply a representative organic soil amendment sample
and written confirmation of the organic soil amendment composition
from the
supplier.
B. Organic Soil Amendments shall
be used in tree and shrub planting areas. The organic soil amendments
will be thoroughly mixed in the top 6 to 8 inches of soil. A soil
test
shall be done after amending the soil, with results not to deviate
from the following ranges:
1. Organic
soil amendments shall not raise the pH of the soil (become more
alkaline), after well mixed into the soil.
2.
Organic soil amendments well mixed into the soil, shall not raise
the salt index of the soil above 2mmhos/cm (millimhos per centimeter)
or 2dS/m (deciSiemens per Meter).
3. Organic
amended soil shall not exceed the C:N (Carbon:Nitrogen) ratio
of 30:1 or be less than 10:1 C:N.
4.
Organic content of the soil after mixing in the organic soil amendment
shall be above 5%.
5.
The organic soil amendments shall be finely shredded and free
of sticks, stones, lumps, and noxious weeds.
2.03 COMMERCIAL FERTILIZERS
A. If required, each tree and shrub
planting site shall have the proper mix of fertilizer elements,
which are specified on the soil lab report as lacking, applied
according to the manufacturer
label. Fertilizers shall be thoroughly incorporated into the entire
tilled planting site to a depth of 6 to 8 inches. Fertilizers
will not just be incorporated into backfill
soil from individual planting holes.
2.04 STAKING MATERIAL
A. Use wire, twine, or strap material
(such as ArborTie®), appropriate for the tree size. (Wire
through a garden hose is unacceptable.)
B. Tree brace straps, designed for
specifically staking trees, shall be used around the tree trunk
in conjunction with wire or twine. Straps shall be 8" to
12" long by 2" (or greater) wide,
high grade webbing material that will not fray or tear easily
and will not cut into or abrade the tree trunk. The straps, typically
used with wire or twine, will have
a grommet at each end.
C. Staking poles shall be standard
"T-post", six feet tall steel dark green or approved
color, or six foot tall wood posts specifically intended for tree
staking.
2.05 WATER
A. Clean and fresh.
B. Transport as required.
2.06 MULCHING MATERIAL
A. Trees and shrubs in turf areas
or other planting beds shall be mulched with a chipped bark and/or
wood mulch not larger than four inches (4") in length or
other materials as
specified by the project plan.
2.07 ANTI-DESICCANT
A. Anti-desiccants for retarding
excessive loss of plant moisture and inhibiting wilt shall be
sprayable, water insoluble, commercially manufactured, and specifically
formulated
to produce an evaporation/transpiration loss barrier.
2.08 TREE WRAP
A. Tree trunk wrapping material,
used to help protect the tree trunk from sunscald, shall be specifically
manufactured for tree trunk protection and shall be pre-approved
by the
city. Tree wrap shall be installed on trees, under warranty, in
October and removed in May.
SECTION
3 EXECUTION
3.01 LAYOUT AND EXCAVATION OF PLANTING AREAS
(Refer to 3.08 and 3.09 for Planting
Illustration)
A. Layout and Staking: Lay out plants
at locations shown on drawings. Use stakes at least one-foot tall
to indicate tree location.
B. Review: Locations of plants shall
be checked in the field and shall be adjusted to exact position
before planting begins.
C. The Contractor shall notify Underground
Utility Locator(s), serving Cheyenne, prior to digging. Contact
City's Representative after utility locates are complete and before
planting
begins, for a final placement review.
D. Planting Site: Till the soil,
in an area four times the width of the root-ball, to a depth of
six to eight inches, if the area to be tilled will not conflict
with structures, plants, major
tree roots, or infrastructure. In this stage, incorporate
organic soil amendments and/or fertilizer according to Section
2.02 A., and 2.03 A. Mix the amendments into the
soil during the soil tilling process. Organic soil is added at
a rate of one inch in depth covering the area tilled. Fertilizer
is added, if needed, according to product label for
tree use. Soil amendments shall not be added to just the
planting pit backfill soil.
E. Excavate B&B tree planting
pits to a width at least twice the diameter of the ball, but to
a depth of one to two inches less than the height of the top most
permanent root, as
noted below in section 3.02.
F. Equipment for Digging Plant
Pits: Use of a tree spade to solely dig plant pits is prohibited.
A tree spade can be used to dig planting holes when the transplant
plants are also dug with
a tree spade. Using a backhoe to dig planting holes is acceptable,
with scarification of the tree pit after excavation - see Section
3.02 C. 2.
G. Signs, access barriers, and
other safety devices shall be used at all times to ensure public
and worker safety, especially after the work site is closed for
the night.
3.02 PLANTING OPERATIONS (Refer
to 3.08 and 3.09 for Planting Illustration)
A. General:
1.
Protect plants at all times from sun or drying winds.
2.
Keep plants that cannot be planted immediately upon delivery in
the shade, well-protected, and well-watered.
B. Handling and De-potting of Plant
Materials:
1.
Avoid all damage to containers and rootballs. If rootball is cracked
or broken during handling, plant shall be rejected.
C. Installation:
1.
Locate the uppermost permanent root emerging from the tree trunk,
by loosening the burlap around the trunk on B&B trees, and
carefully removing soil along the trunk.
2.
Plant Pit: Measure the depth of the root-ball between the uppermost
permanent root and the bottom of the root-ball. The depth of the
planting hole shall cause the uppermost
root to be one to two inches above the surrounding soil grade.
The soil at the bottom of the planting pit shall be undisturbed
and provide a solid foundation for
the plant. Scarify sides of planting pit, thoroughly breaking
up all surfaces and eliminating all "glazed" areas.
3.
Remove bottom of the wire basket prior to setting into the pit.
4.
Positioning: Plants shall be set in the center of the pit, and
kept plumb. The uppermost root shall be kept between surrounding
soil grade and two inches above the surrounding soil
grade. If there is more than two inches of soil on the top
of the rootball above the uppermost root, remove excess soil from
the top of the rootball leaving
two inches of soil covering the root system.
5.
Back-filling:
a.
Backfill around the rootball, using the soil removed from the
planting pit, to stabilize the tree in the planting pit. After
tree is placed in the hole and stabilized with some
backfill soil, remove the remainder of the wire basket and remove
the remaining burlap from around the top one-half to two-thirds
of the rootball. All wire, string,
the top portion of burlap around the rootball, and any other shipping
material shall be removed from around the rootball.
b.
Brace each plant plumb and rigidly in position until planting
soil has been placed around the bottom of the rootball. After
two-thirds of the hole has been filled with backfill
soil, use water at low pressure to settle the soil around the
rootball. Do not tamp or pack the soil around the root-ball.
c.
The uppermost permanent root emerging from the trunk on the tree
or shrub shall be between surrounding soil grade to two inches
above the surrounding natural soil
grade of the planting pit. The top permanent root shall not
be below the surrounding soil grade.
d.
No additional soil shall be placed on the top of the rootball,
other than the two inches of soil left covering the roots from
the nursery soil.
e.
Contractor shall remove excessive excavated planting backfill
material from the site as directed by the City's Representative.
6.
Staking and/or Guying: Stake or guy as outlined in Section 3.03.
D. Tree Wells: A 2 to 3 inch
high earth berm shall be formed on the outside perimeter of the
planting pit, unless otherwise specified. (For mulching see Section
3.04).
E. Tree Wrap: Wrap, as detailed,
all deciduous sensitive barked trees in the month of October and
remove after full leaf expansion in the spring. Do use any device
that will puncture
or abrade the bark of the tree to secure tree wrap.
F. Watering: Water each plant immediately
after planting. Use a deep watering device or surface application,
allowing water to soak into the rootball and backfill soil. Contractor
shall provide watering services for proper frequency and amount,
for the health and full development of all contractor-installed
plant materials, until Final Acceptance
and as required during the guarantee period, including winter
months.
1.
The amount will be no less than ten gallons of water for each
one inch caliper tree trunk measure.
2.
Frequency will depend upon the retention of plant available water
in the soil.
G. Labels: Do not remove nursery-type
plant labels or any City of Cheyenne tags from the trees until
after Final Landscape Acceptance.
3.03 STAKING AND GUYING (Refer
to 3.08 and 3.09 for Planting Illustration)
A. General:
1.
Balled and Burlapped (B&B) Trees shall be able to stand upright
without support. Trees shall be staked, if so indicated, on the
planting detail plan.
2.
All plant materials shall remain plumb and straight for all given
conditions from installation through the guarantee period.
B. Staking:
1.
Trees shall be staked and guyed as detailed below.
2.
Locate (two) stakes in a line with the trunk of the tree, parallel
or in-line with prevailing wind. Drive stakes at least eighteen
(18) inches down into undisturbed soil.
3.
Support straps (web straps designed for tree staking) shall be
placed around the trunk in a single loop. Run wire or other line
through grommets on support strap. Staking
support line shall be installed parallel to the ground. Trees
shall be guyed to allow the tree trunk to sway two inches (2").
4.
A city approved durable wire or twine covering shall be installed
between the tree strap and the post to reduce human contact injury
and to improve visibility of the wire or
line.
5.
If metal t-posts are used, a city approved durable cap shall be
installed on top of the t-post to reduce human contact injury
and to improve visibility of the post.
3.04 MULCHING (Refer
to 3.08 and 3.09 for Planting Illustration)
A. Install a 3 to 4 inch deep layer
of specified mulch within a planting area as defined by the project
specifications. Mulch will not touch tree trunks.
3.05 CLEANUP
A. Keep all areas of work clean,
neat and orderly.
B. Clean up and remove all materials
and debris from the entire work area prior to Initial and Final
Acceptance.
3.06 MAINTENANCE
A. If the irrigation system is not
available for proper watering at the time of installation, the
Contractor shall provide water to plants to maintain soil moisture
in the Available Soil
Moisture Percent range of 40% to 75%. Failure of the irrigation
system shall not relieve Contractor of the responsibility to provide
the required water.
3.07 WINTER WATERING
A. Contractor shall provide winter
watering of all trees and other materials as needed during the
warranty period. Contractor shall maintain a log of all watering
and maintenance
operations.
3.08
Illustration of Planting Containerized Trees and Shrubs (PDF
File)
3.09
Illustration of Planting Balled & Burlapped (B&B) Trees
(PDF File)
END OF TREE SELECTION AND PLANTING SPECIFICATIONS
PART 2 - TREE RETENTION
AND PROTECTION
This section provides standards and guidelines for the retention
and protection of trees and high-value shrubs for any proposed
public works or construction project.
4.00 TREE RETENTION AND PROTECTION PLAN
A. Develop with the aid of City
Forestry or a Project Consulting Arborist a written Tree Protection
plan for all trees to be retained on the project site.
4.10 REFERENCE STANDARDS AND GUIDELINES
A. Contractor shall comply with
applicable requirements and recommendations of the most current
versions of the following standards and guidelines. Where these
conflict with
other specified requirements, the more restrictive requirements
shall govern.
1.
ANSI Z133.1-2006 (or more recent version) American National Standard
for Arboricultural Operations
2.
ANSI A300 (Part 1) - 2001 Pruning, (Part 2) - 2004 Fertilization,
(Part 3) - 2006 Support Systems, or more recent versions, Standard
Practices for Trees, Shrubs and Other
Woody Plant Maintenance, and Best Management Practices companion
publications.
3.
GUIDE FOR PLANT APPRAISAL - 9TH EDITION (or more recent version)
Authored
by the Council of Tree and Landscape Appraisers; published by
the International Society of Arboriculture.
4.20 DEFINITIONS
A. CRITICAL ROOT ZONE: Generally,
all of the ground area within the tree's dripline.
B. DIAMETER (CALIPER): The size
(in inches) of a tree's trunk is measured at: [1]-six (6) inches
above grade for trunk diameters up to and including four (4) inches;
[2]-twelve
(12) inches above grade for trunk diameters from four (4) inches
up to and including eight (8) inches; and [3]-four and a half
(42) feet above grade for trunk diameters
greater than eight (8) inches; in accordance with guidelines established
in the "Guide for Plant Appraisal" (see Section 5.00).
All measurements should be rounded
to the nearest inch.
C. DRIPLINE: The outermost edge
of the tree's canopy or branch spread. The area within a tree's
dripline is all the ground under the total branch spread.
D. HIGH-VALUE SHRUB: Any specimen
shrub with an appraised value of $100.00 or more.
E. PROJECT CONSULTING ARBORIST:
An independent consultant with a degree in a field related to
arboriculture, and at least five years field experience in tree
preservation
or on-site monitoring of public works or construction projects
involving tree retention and protection. The consultant should
be a member in good standing with
the International Society
of Arboriculture and a professional consulting arborist
as recognized by the American
Society of Consulting Arborists.
F. TREE PROTECTION AREA: Generally, a
tree protection area should consist of the ground encompassing
from 1.5 (minimum) to 2.0 times the distance between the trunk
and dripline, or one linear foot away from the trunk base for
every inch diameter of the trunk, whichever is greater. Areas
of ground covered by pavement, buildings, or
other permanent structures where the presence of roots is minimal
or negligible, are excluded. The area under or within the tree's
dripline is also referred to as the "Critical
Root Zone".
With groups of trees or where an
array effect is present, there may be discontinuous (non-overlapping)
perimeters of tree protection areas which result in difficult
to maintain or ineffective tree
protection fencing. In these cases, even though tree protection
areas do not overlap, they should be treated as though they do,
if the distance between the perimeters
of such areas is less than thirty (30) feet. In effect, this will
artificially enlarge the area of tree protection, but will result
in a clearly defined, manageable area.
4.30 GENERAL REQUIREMENTS
A. There shall be daily supervision
of field crews by the City Forestry Staff or Project Consulting
Arborist during the critical phases of the project: for example,
demolition of
existing concrete; root pruning; construction of retaining walls
or sand walls; and construction of new curb or sidewalk in tree
protection areas.
B. To prevent or minimize soil compaction,
designated routes for equipment and foot traffic by work crews
shall be determined prior to commencing construction activities,
and shall
be indicated in the tree protection plan. These routes shall be
marked at the site, prior to commencement of construction, with
tree protection fencing and signage
as specified in the Site Plan and Sections 6.05 & 6.06 (tree
protection fencing).
C. Motorized equipment and trailers,
including but not limited to tractors, Bobcats, bulldozers, trackhoes,
trucks, cars, and carts shall not be allowed access within tree
protection
areas. Should access be necessary within designated tree protection
areas, the existing grade shall be covered with six to eight inches
of wood chip mulch to
help distribute the weight of equipment and to minimize soil compaction
and rutting. Plywood and/or mulch are not acceptable bridging
materials for driving over exposed
tree roots. Exposed tree roots shall not be driven over. The Director
of Forestry or Project Consulting Arborist shall be notified and
shall approve of the access and
driving surface prior to its use.
D. Materials and supplies shall
not be stockpiled or stored within the tree protection area. Should
temporary storage be necessary within designated tree protection
areas, the
existing grade shall be covered with double, overlapping sheets
of one inch thick plywood, or six to eight inches of wood chip
mulch to help distribute the weight of materials
or supplies and to minimize soil compaction.
E. Under no circumstances shall
any objects or materials be leaned against or supported by a tree's
trunk, branches, or exposed roots. The attachment or installation
to trees
of any sign, cable, wire, nail, swing, or any other material that
is not needed to help support the natural structure of the tree
is prohibited. Standard arboricultural techniques
such as bracing or cabling that are performed by professional
arborists are acceptable upon approval by the Director of Forestry
or Project Consulting Arborist.
F. A monetary fine may be imposed
by the project coordinator if the fenced tree protection area
is breached.
5.00 DEMOLITION AND RECONSTRUCTION
ACTIVITIES AND TREE PROTECTION
5.10 DEMOLITION OF EXISTING CONCRETE
Caution should be used during removal of existing street, curb,
gutter, sidewalk, drain inlets, and other concrete demolition,
to minimize injury to tree root systems. The following procedures
should be used when removing existing concrete.
A. Breaking of the existing concrete
for removal should be done in a manner that will minimize ground
disturbance.
B. Curbs and sidewalks within designated
tree protection areas and critical root zones shall be removed
by hand. When removing existing sidewalks and curbs, care should
be taken
to avoid injury to roots located under, over, or adjacent to paved
and concrete surfaces.
C. Roots and root-trunk flares growing
over curbs should not be injured during breaking of curbs and
removal of debris. Wood and bark tissues shall not be injured
by striking
tissues with equipment.
D. During the removal of concrete,
all root systems and soil areas exposed shall not be disturbed.
E. Motorized equipment and trailers,
including tractors, Bobcats, bulldozers, trackhoes, trucks, cars,
and carts are to be limited to access on the existing paved street
only. Access
is discouraged behind the curb within tree protection areas.
F. Should access be necessary within
designated tree protection areas, the existing grade shall be
covered with double, overlapping sheets of one inch thick plywood,
or six (6)
to eight (8) inches of wood mulch to help distribute the weight
of equipment and to minimize soil compaction and rutting. Plywood
and/or mulch are not acceptable
bridging materials for driving over exposed tree roots. Exposed
tree roots shall not be driven over. The Director of Forestry
or Project Consulting Arborist shall be
notified and shall approve of the access and driving surface prior
to its use.
5.20 CONSTRUCTION OF SIDEWALKS, CURBS,
CONCRETE PAVING AND DRAINAGE INLETS
The following procedures shall be used when constructing sidewalks,
curbs, concrete paving, and drainage inlets.
A. Keep all materials and equipment
within the street bounded by existing curbs.
B. Protect exposed roots from contamination
by stabilization materials and concrete.
C. Locate concrete washout areas
away from roots and tree protection areas.
D. When excavating for the construction
of inlets, excavated soil shall be deposited in trucks and hauled
off or deposited temporarily on one inch thick plywood outside
the critical
root zone. Excavated and fill soil shall not be deposited, even
temporarily, on unprotected natural grade within a tree's dripline.
E. After proper root pruning (see
section 6.04), as needed, cover exposed roots within thirty (30)
minutes to minimize desiccation. Roots may be covered with soil,
mulch, or
moistened burlap, and shall be kept moist during the period until
the final grade or soil fill is completed.
F. Where possible, sidewalks should
be raised, narrowed, curved, or relocated to prevent cutting and
removing major roots (i.e., roots greater than three inches in
diameter).
G. Limit soil fill to a maximum
of two (2) inches fill over the natural grade within critical
root zones. Fill should consist of sandy loam topsoil. Clay soils
shall not be used as fill.
When using fill soil, the existing surface to receive fill should
be scarified prior to filling. Any filling operation should not
occur during water saturated soil conditions.
H. Provide for easy concrete removal
and replacement where an obvious raised root may cause sidewalk
cracking in the future. This can be accomplished by installing
an expansion
joint on either side of the root or by etching the concrete on
either side of the root to allow that particular section to be
broken out and replaced. Compaction rating
for the replacement walkway should not exceed 80% Proctor density.
Tree roots will continue to slowly add girth every year; therefore,
the base material needs to be
malleable (e.g., suitable sub grade aggregates, crushed granite,
compacted sand, or gravel) to prevent a fulcrum or pressure point
which can crack or heave the walkway.
I. Root Restricting Barriers: Where
appropriate, and under the direction of the Director of Forestry
or Project Consulting Arborist, root restricting barriers can
be installed with
a minimal amount of disturbance. A gravel layer three to four
inches in depth below the sidewalk and curb discourages root growth
directly below these concrete surfaces.
There are several other landscape related materials used as barriers
to root growth, especially away from sidewalks, curbs and streets.
Three such materials are:
1. An artificial
thread woven fabric with holes approximately 1/26th-inch
square separated by strands approximately 1/26th-inch thick, with
strands fused together.
2. Copper screen
has been shown to be effective in controlling seedling root
growth, 14-mesh or smaller copper wire screen (1/16 inch square
openings or smaller).
3. BioBarrier.
A landscape fabric with Trifluralin (herbicide) impregnated
pellets attached to the fabric. The pellets are impregnated with
the herbicide Trifluralin which is released slowly
over several years. The herbicide will form a "vapor"
barrier where roots will not grow, anywhere from a half inch to
2 inches from the herbicide laced barrier.
The herbicide is not systemic and should not kill anymore of the
root or damage the health of the tree.
a.
After a two (2) foot deep, narrow trench is dug adjacent to the
curb, sidewalk, or other structure involved, and after any affected
roots are properly pruned (see section
6.04), the root barrier of choice should be placed against
the side of the wall closest to the roots that were severed (side
of the wall farthest from the structure
being protected).
Note: Root
barrier installations should not be used if large, existing roots
(four (4) inches or larger in diameter) will be severed. The nylon
fabric and copper screen will constrict
(and hopefully strangle) the roots to the size of the openings
in the material. Roots will be greatly stunted and/or diverted
except for knobs that form against the barriers.
The barrier should be installed from above the surface of the
soil to a depth of at least eighteen (18) to twenty-four (24)
inches (in a vertical plane). Mechanical barriers
must be undamaged above and below the soil to be effective.
J. Cut the soil around trees instead
of using backhoe or blade type equipment. Backhoes and blades
can tear roots causing more damage to the tree. Tree roots shall
be cut
cleanly where damaged.
1.
Excavate soil by hand at the construction cut limit to a depth
of thirty (30) inches or to the depth of the required root cut,
whichever is less.
2.
Prune roots as specified in section 6.04.
3.
Protect exposed roots as specified in section 6.02,E.
K. Concrete or chemicals spilled
within tree protection areas should be completely removed. Contaminated
soil shall be completely removed at the time of the spill and
removed
by hand without disturbance to root systems. Appropriate soil
should be added as necessary to restore the grade.
5.30 IRRIGATION OR UTILITY INSTALLATION
A. PROTECTION OF TREES AND HIGH-VALUE
SHRUBS:
Contractor
shall protect all trees and high-value shrubs from injury due
to irrigation related work. All injuries to trees and high-value
shrubs shall be mitigated to the satisfaction
of the City, and if appropriate, in accordance with guidelines
established in the "Guide for Plant Appraisal. All costs
of such mitigating shall be charged to and
paid by the Contractor.
All irrigation
lines shall be indicated on construction plans and pre-approved
by the Director of Forestry or Project Consulting Arborist. No
irrigation lines shall be located within
10 feet of any existing tree trunk. (See Section B-5 below).
B. EXISTING TREES
1.
The Director of Forestry or Project Consulting Arborist shall
be notified prior to any trenching or excavation that is known
or suspected to involve cutting of any roots more than
two inches in diameter.
2.
All trenching or other work under the dripline of any tree shall
be done by hand or by other methods which will prevent breakage
or other injury to branches and roots.
3.
Where it is necessary to excavate within the critical root zone
of existing trees, contractor shall use all possible care to avoid
injury to trees and tree roots. Excavation,
in areas where two inch diameter and larger roots occur, shall
be done by hand with approved hand tools. Where possible, tree
roots two inches or larger
in diameter shall be tunneled or bored under and shall be covered
with moistened burlap to prevent excessive drying.
4.
Wherever a trenching machine exposes roots smaller than two inches
in diameter, such roots extending through the trench wall shall
be hand pruned (see section 6.04).
All trenches within critical root zones shall be closed within
twelve hours. If this is not possible, the trench walls shall
be covered with burlap and kept moistened.
Prior to backfilling, Contractor shall contact the Director of
Forestry or Project Consulting Arborist to inspect the condition
and treatment of roots larger than
two inches in diameter injured by trenching.
5.
Horizontal directional boring (auger tunneling), rather than open
trenching, should be used for irrigation line or other utility
installation within one half foot linear distance
from the trunk base for every inch of trunk diameter (e.g., 30
inch diameter tree trunk equals a distance of 15 feet).
5.40 ROOT PRUNING
A. Tree roots shall not be
pruned or cut unless their removal is unavoidable or absolutely
necessary. The Director of Forestry or Project Consulting Arborist
shall be notified prior
to any operation known or suspected to involve cutting roots more
than two inches in diameter. The Director of Forestry or Project
Consulting Arborist shall be notified
immediately in the event that roots in excess of that described
above are cut, torn, ripped, or otherwise injured.
B. Removal of roots greater than
one inch diameter or parts of roots that are injured or diseased
should be performed as follows:
1.
Preserve the root bark ridge (similar in structure and function
to a branch bark ridge). Directional root pruning is the recommended
technique and should be used during
hand excavation around tree roots. Roots are similar to branches
in their response to pruning practices. With directional root
pruning, objectionable and severely
injured roots are properly cut to a lateral root, if possible,
that is growing downward or in a favorable direction.
2.
All roots needing to be pruned or removed shall be cut cleanly
with sharp hand tools, with oversight by the Director of Forestry
or Project Consulting Arborist. No wound
dressings shall be used.
3.
Recommended root pruning tools:
a.
By-pass type lopper.
b.
By-pass type pruner.
c.
Large and small hand saws.
d.
Sharp knife for roots less than 1 inch in diameter.
e.
Trowel or small shovel.
C. Root Pruning Near Sidewalks
1.
Root pruning should be done carefully, by hand, to achieve the
objective of reducing future sidewalk problems as well as preserving
the trees. Removing anchoring roots
or causing injuries in anchoring roots and root flares can cause
future decay and windthrow hazards. Indiscriminate cutting of
vigorous roots results in their resprouting
so that several more new roots may grow from the cut end, back
under the sidewalk, thereby reducing the time between sidewalk
repairs. Roots can be managed
in the ground without significant harm to trees, if care is taken
to avoid injuries that lead to root and trunk decay.
2.
Directional root pruning is recommended because it considers the
tree's response to root pruning and decay. With directional root
pruning, roots are cut to a large lateral,
if possible, that is growing downward or in a more favorable direction.
The pruned root ends will be less likely to resprout, since a
large lateral can assume the new
terminal role of the root.
Proper
removal of selected roots or parts of roots can direct roots away
from sidewalks in the future. Procedures for root pruning directly
next to sidewalks are as follows:
a.
Hand dig a trench six to eight inches in depth at the edge of
the planting strip and sidewalk.
b.
Remove all roots less than two inches in diameter in this trench
back to a desirable lateral root, preserving the root bark ridge.
If careful excavation does not reveal
a desirable lateral root within twelve inches of the exposed root
in question, then the exposed root shall be cut so that a minimal
amount of root is removed.
c.
Small root bundles, the source of future sidewalk problems, should
also be removed at this time.
3.
All roots larger than two inches in diameter should be examined
by the Director of Forestry or Project Consulting Arborist in
terms of their role in anchoring the tree.
a.
All roots that contribute significantly to anchorage should be
preserved. Prune all other roots less than two inches in diameter
to sound, downward growing lateral roots
that are at least one half the size of the root being removed.
b.
All roots larger than four inches in diameter are to be preserved
unless their removal is absolutely necessary. Preservation of
large roots may require:
i. Reducing
the sidewalk width near the root flare
ii. Ramping or bridging the sidewalk over the roots to allow for
root growth
iii. Redirecting the sidewalk away from the root flair of the
tree.
4.
Tree guying subsequent to root pruning: Smaller trees may be able
to be reasonably guyed or otherwise supported.
a.
Upon review of on-site root pruning and constructing grading limits,
the Director of Forestry or Project Consulting Arborist shall
determine if smaller existing trees subject
to root pruning can be reasonably guyed or otherwise stabilized.
Contractor shall retain a qualified tree service company to complete
tree guying and stabilization
in accordance with American National Standard (ANSI) A300 (Part
3) as referenced in Section 5.00. Tree service company shall be
licensed by the City
of Cheyenne, through the Director of Forestry's Office.
5.50 TREE PROTECTION FENCING
A. Tree protection fencing should
be installed behind the existing curb as close to the street as
construction will allow in areas where the street surface will
be removed and replaced.
Tree protection areas shall be designated on construction
documents, and fencing locations should be staked for approval
by the Construction Manager and Director
of Forestry or Project Consulting Arborist.
B. Tree protection fences should
be constructed of one of the following:
1.
Galvanized chain-link - six feet in height. Posts should be installed
on ten foot centers (maximum), at a depth of three feet minimum.
Installation of post shall
not result in injury to surface roots or root flares of trees.
2.
Colored (orange), molded plastic construction fencing, four feet
in height. T-Posts, six feet tall, should be installed on a maximum
of ten foot centers to support
the fencing.
C. Fencing shall be installed to
completely enclose the tree protection areas.
D. Tree protection fencing shall
be installed prior to any construction activity and shall remain
until its removal is authorized by the Director of Forestry or
Project Consulting Arborist.
5.60 TREE PROTECTION SIGNS
A. A sign shall be mounted on tree
protection fencing at fifty foot intervals warning constructing
personnel and the public to keep out of the tree protection areas.
6.00 PROJECT SITE MONITORING
A. As determined by the Director
of Forestry for projects of sufficient size to warrant such, a
Project Consulting Arborist should be retained to enforce and
monitor the Tree Retention
and Protection objectives. The project site should be monitored
a minimum of two times weekly, more frequently at the start of
the project until all procedures
and specifications are understood and properly executed by all
parties.
7.00 INJURIES TO EXISTING PLANTS - DAMAGE
PENALTIES - Trees can have an extremely high value!
A. TREE AND HIGH-VALUE SHRUB APPRAISAL:
1.
All trees and high-value shrubs will be evaluated and appraised
by the Director of Forestry or Project Consulting Arborist using
the Guide for Plant Appraisal as referenced
in Section 4.10, and a list of all tree values for the project
will be on file in the Construction Manager's office. Any tree
or other plant requiring retention or protection
that is not on the list shall be appraised by the Director of
Forestry or Project Consulting Arborist as necessary to comply
with this damage penalty.
2.
Documentation for appraisals will consist of: [1] - measurement
of plant size; [2] - identification by common and botanical names;
[3] - current condition (overall health,
injuries, visible hazard status, etc.) and [4] - location factors
as described in the "Guide for Plant Appraisal". Photographs
may be taken of certain trees and shrubs
to document debilitating condition factors.
3.
The minimum threshold level for plants to be damage appraised
shall be a minimum of $100.00 cumulative damage.
B. Trees and other plants designated
as requiring retention or protection shall be identified and located
on construction plans. Loss of, or partial injury to, any of these
plants due
to Contractor neglect or improper construction activities will
result in liquidated damages for the assessed value of the tree
as determined by the Director of Forestry
or Project Consulting Arborist.
C. Trees determined as requiring
"general protection" or "special protection"
in the construction areas and in other key locations should be
clearly identified by the Director of
Forestry or Project Consulting Arborist. Loss or partial injury
to any of these trees due to Contractor neglect or improper construction
activities will result in liquidated damages
for the assessed value of the trees as determined by the Director
of Forestry or Project Consulting Arborist. Injury to a portion
of these trees will be assessed by
the Director of Forestry or Project Consulting Arborist and a
corresponding portion of the liquidated damages will be assessed
to the Contractor.
D. A fine will be levied against
the Contractor for each incident of construction damage, including
construction traffic, within designated tree protection areas.
Any fine shall be
independent of any applicable liquidated damages for the assessed
value of the tree or tree part.
E. Trees or roots visibly and unnecessarily
injured will cause the City to withhold from the Contractor an
assessed amount conforming to the requirements stipulated above,
for a period
of one full year. After that period the impact of the injury to
any tree will be assessed by the Director of Forestry or the Project
Consulting Arborist.
F. If any trees or shrubs designated
to be retained or protected are injured and replacement is justified,
an equivalent number of diameter inches of trees or shrubs of
same or
similar species shall be furnished and planted by the Contractor
in accordance with "Guide for Plant Appraisal" (See
4.10 A. 3.)
8.00 SUBMITTALS
A. Proposed methods and schedule
for effectuating tree and other plant protection shall be submitted
for approval. Contractor shall submit a construction schedule
which includes
a time frame for work near existing plants. Approval the construction
schedule shall be obtained from the Director of Forestry prior
to commencement of construction
near tree protection areas.
B. Proposed methods, materials,
and schedule for root pruning, branch pruning, and other tree
maintenance shall be submitted for approval to the Director of
Forestry or Project
Consulting Arborist who will then mark the location of root pruning
lines in the field prior to the operation. If possible, root pruning
should occur between autumn leaf
drop and spring foliation. Root pruning during the growing
season shall require approval of the Director of Forestry or Project
Consulting Arborist.
9.00 TREE AND OTHER PLANT MAINTENANCE DURING
AND AFTER COMPLETION OF CONSTRUCTION
A. Proper maintenance should include,
but without limitation to: structural and remedial pruning; watering;
mulching; reducing soil compaction; fertilization; insect and
disease
control; soil and tissue analysis; aeration; and wound treatment.
B. The timing, duration and frequency
of necessary maintenance practices should be determined by the
Director of Forestry or Project Consulting Arborist, based on
factors associated
with the site and affected plants.
END OF TREE RETENTION AND PROTECTION SPECIFICATIONS
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