Exterior_Improvements.pdf

United States Air Force Academy Repair HTHW Phase 1/4

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SECTION 32 12 16 - ASPHALT PAVING

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section.

1.2 SUMMARY

A. Section Includes:

1. Cold milling of existing hot-mix asphalt pavement.

2. Hot-mix asphalt patching.

3. Hot-mix asphalt paving.

4. Hot-mix asphalt paving overlay.

5. Asphalt surface treatments.

6. Pavement-marking paint.

B. Related Sections:

1. Division 02 Section "Structure Demolition" for demolition, removal, and recycling of existing asphalt pavements, and for geotextiles that are not embedded within courses of asphalt paving.

2. Division 31 Section "Earth Moving" for aggregate subbase and base courses and for aggregate pavement shoulders.

3. Division 32 Sections for other paving installed as part of crosswalks in asphalt pavement areas.

4. Division 32 Section "Concrete Paving Joint Sealants" for joint sealants and fillers at paving terminations.

1.3 DEFINITION

A. Hot-Mix Asphalt Paving Terminology: Refer to ASTM D 8 for definitions of terms.

1.4 SUBMITTALS

A. Product Data: For each type of product indicated. Include technical data and tested physical and performance properties.

1. Job-Mix Designs: Certification, by authorities having jurisdiction, of approval of each job mix proposed for the Work.

2. Job-Mix Designs: For each job mix proposed for the Work.

B. Shop Drawings: Indicate pavement markings, lane separations, and defined parking spaces.

Indicate, with international symbol of accessibility, spaces allocated for people with disabilities.

C. Samples: For each paving fabric, 12 by 12 inches minimum.

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D. Samples for Verification: For the following products, in manufacturer's standard sizes unless otherwise indicated:

1. Each paving fabric, 12 by 12 inches minimum.

E. Qualification Data: For qualified manufacturer and Installer.

F. Material Certificates: For each paving material, from manufacturer.

G. Material Test Reports: For each paving material.

1.5 QUALITY ASSURANCE

A. Manufacturer Qualifications: A paving-mix manufacturer registered with and approved by authorities having jurisdiction or the DOT of state in which Project is located.

B. Testing Agency Qualifications: Qualified according to ASTM D 3666 for testing indicated.

C. Regulatory Requirements: Comply with materials, workmanship, and other applicable requirements of the State of Colorado DOT for asphalt paving work.

1. Measurement and payment provisions and safety program submittals included in standard specifications do not apply to this Section.

D. Preinstallation Conference: Conduct conference at Project site.

1. Review methods and procedures related to hot-mix asphalt paving including, but not limited to, the following:

a. Review proposed sources of paving materials, including capabilities and location of plant that will manufacture hot-mix asphalt.

b. Review condition of subgrade and preparatory work.

c. Review requirements for protecting paving work, including restriction of traffic during installation period and for remainder of construction period.

d. Review and finalize construction schedule and verify availability of materials, Installer's personnel, equipment, and facilities needed to make progress and avoid delays.

1.6 DELIVERY, STORAGE, AND HANDLING

A. Deliver pavement-marking materials to Project site in original packages with seals unbroken and bearing manufacturer's labels containing brand name and type of material, date of manufacture, and directions for storage.

B. Store pavement-marking materials in a clean, dry, protected location within temperature range required by manufacturer. Protect stored materials from direct sunlight.

1.7 PROJECT CONDITIONS

A. Environmental Limitations: Do not apply asphalt materials if subgrade is wet or excessively damp, if rain is imminent or expected before time required for adequate cure, or if the following conditions are not met:

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1. Prime Coat: Minimum surface temperature of 60 deg F.

2. Tack Coat: Minimum surface temperature of 60 deg F.

3. Slurry Coat: Comply with weather limitations in ASTM D 3910.

4. Asphalt Base Course: Minimum surface temperature of 40 deg F and rising at time of placement.

5. Asphalt Surface Course: Minimum surface temperature of 60 deg F at time of placement.

B. Pavement-Marking Paint: Proceed with pavement marking only on clean, dry surfaces and at a minimum ambient or surface temperature of 40 deg F for oil-based materials, and not exceeding 95 deg F.

PART 2 - PRODUCTS

2.1 AGGREGATES

A. General: Use materials and gradations that have performed satisfactorily in previous installations.

B. Coarse Aggregate: ASTM D 692, sound; angular crushed stone, crushed gravel, or cured, crushed blast-furnace slag.

C. Fine Aggregate: ASTM D 1073 or AASHTO M 29, sharp-edged natural sand or sand prepared from stone, gravel, cured blast-furnace slag, or combinations thereof.

1. For hot-mix asphalt, limit natural sand to a maximum of 20 percent by weight of the total aggregate mass.

D. Mineral Filler: ASTM D 242 or AASHTO M 17, rock or slag dust, hydraulic cement, or other inert material.

2.2 ASPHALT MATERIALS

A. Asphalt Binder: AASHTO M 320 or AASHTO MP 1a, PG 64-22.

B. Asphalt Cement: ASTM D 3381 for viscosity-graded material.

C. Prime Coat: ASTM D 2027, medium-curing cutback asphalt, MC-30 or MC-70.

D. Prime Coat: Asphalt emulsion prime coat complying with State of Colorado DOT requirements.

E. Tack Coat: ASTM D 977 or AASHTO M 140 emulsified asphalt, or ASTM D 2397 or AASHTO M 208 cationic emulsified asphalt, slow setting, diluted in water, of suitable grade and consistency for application.

F. Fog Seal: ASTM D 977 or AASHTO M 140 emulsified asphalt, or ASTM D 2397 or AASHTO M 208 cationic emulsified asphalt, slow setting, factory diluted in water, of suitable grade and consistency for application.

G. Water: Potable.

H. Undersealing Asphalt: ASTM D 3141, pumping consistency.

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2.3 AUXILIARY MATERIALS

A. Herbicide: Commercial chemical for weed control, registered by the EPA. Provide in granular, liquid, or wettable powder form.

B. Sand: ASTM D 1073 or AASHTO M 29, Grade Nos. 2 or 3.

C. Paving Geotextile: AASHTO M 288, nonwoven polypropylene; resistant to chemical attack, rot, and mildew; and specifically designed for paving applications.

D. Joint Sealant: ASTM D 6690 or AASHTO M 324, Type I, hot-applied, single-component, polymer-modified bituminous sealant.

E. Pavement-Marking Paint: Alkyd-resin type, lead and chromate free, ready mixed, complying with AASHTO M 248, Type N; colors complying with FS TT-P-1952.

1. Color: White and Yellow.

F. Pavement-Marking Paint: MPI #32 Alkyd Traffic Marking Paint.

1. Color: White and Yellow.

G. Glass Beads: AASHTO M 247, Type 1.

2.4 MIXES

A. Hot-Mix Asphalt: Dense, hot-laid, hot-mix asphalt plant mixed, approved by authorities having jurisdiction and designed according to procedures in AI MS-2, "Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types."

1. Provide mixes with a history of satisfactory performance in geographical area where Project is located.

2. Provide mixes complying with composition, grading, and tolerance requirements in ASTM D 3515 for the following nominal, maximum aggregate sizes:

a. Base Course: 1 inch.

b. Surface Course: 1/2 inch.

B. Emulsified-Asphalt Slurry: ASTM D 3910, Type 1.

PART 3 - EXECUTION

3.1 EXAMINATION

A. Verify that subgrade is dry and in suitable condition to begin paving.

B. Proof-roll subgrade below pavements with heavy pneumatic-tired equipment to identify soft pockets and areas of excess yielding. Do not proof-roll wet or saturated subgrades.

1. Completely proof-roll subgrade in one direction. Limit vehicle speed to 3 mph.

2. Proof roll with a loaded 10-wheel, tandem-axle dump truck weighing not less than 15 tons.

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3. Excavate soft spots, unsatisfactory soils, and areas of excessive pumping or rutting, as determined by Architect, and replace with compacted backfill or fill as directed.

C. Proceed with paving only after unsatisfactory conditions have been corrected.

D. Verify that utilities, traffic loop detectors, and other items requiring a cut and installation beneath the asphalt surface have been completed and that asphalt surface has been repaired flush with adjacent asphalt.

3.2 COLD MILLING

A. Clean existing pavement surface of loose and deleterious material immediately before cold milling. Remove existing asphalt pavement by cold milling to grades and cross sections indicated.

1. Mill to a depth of 1-1/2 inches.

2. Mill to a uniform finished surface free of excessive gouges, grooves, and ridges.

3. Control rate of milling to prevent tearing of existing asphalt course.

4. Repair or replace curbs, and other construction damaged during cold milling.

5. Excavate and trim unbound-aggregate base course, if encountered, and keep material separate from milled hot-mix asphalt.

6. Transport milled hot-mix asphalt to asphalt recycling facility.

7. Keep milled pavement surface free of loose material and dust.

3.3 PATCHING

A. Hot-Mix Asphalt Pavement: Saw cut perimeter of patch and excavate existing pavement section to sound base. Excavate rectangular or trapezoidal patches, extending 12 inches into adjacent sound pavement, unless otherwise indicated. Cut excavation faces vertically.

Remove excavated material. Recompact existing unbound-aggregate base course to form new subgrade.

B. Tack Coat: Apply uniformly to vertical surfaces abutting or projecting into new, hot-mix asphalt paving at a rate of 0.05 to 0.15 gal./sq. yd..

1. Allow tack coat to cure undisturbed before applying hot-mix asphalt paving.

2. Avoid smearing or staining adjoining surfaces, appurtenances, and surroundings.

Remove spillages and clean affected surfaces.

C. Patching: Partially fill excavated pavements with hot-mix asphalt base mix and, while still hot, compact. Cover asphalt base course with compacted, hot-mix surface layer finished flush with adjacent surfaces.

3.4 REPAIRS

A. Leveling Course: Install and compact leveling course consisting of hot-mix asphalt surface course to level sags and fill depressions deeper than 1 inch in existing pavements.

1. Install leveling wedges in compacted lifts not exceeding 3 inches thick.

B. Crack and Joint Filling: Remove existing joint filler material from cracks or joints to a depth of 1/4 inch.

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1. Clean cracks and joints in existing hot-mix asphalt pavement.

2. Use emulsified-asphalt slurry to seal cracks and joints less than 1/4 inch wide. Fill flush with surface of existing pavement and remove excess.

3. Use hot-applied joint sealant to seal cracks and joints more than 1/4 inch wide. Fill flush with surface of existing pavement and remove excess.

3.5 SURFACE PREPARATION

A. General: Immediately before placing asphalt materials, remove loose and deleterious material from substrate surfaces. Ensure that prepared subgrade is ready to receive paving.

B. Herbicide Treatment: Apply herbicide according to manufacturer's recommended rates and written application instructions. Apply to dry, prepared subgrade or surface of compacted-aggregate base before applying paving materials.

1. Mix herbicide with prime coat if formulated by manufacturer for that purpose.

C. Prime Coat: Apply uniformly over surface of compacted unbound-aggregate base course at a rate of 0.15 to 0.50 gal./sq. yd.. Apply enough material to penetrate and seal but not flood surface. Allow prime coat to cure.

1. If prime coat is not entirely absorbed within 24 hours after application, spread sand over surface to blot excess asphalt. Use enough sand to prevent pickup under traffic.

Remove loose sand by sweeping before pavement is placed and after volatiles have evaporated.

2. Protect primed substrate from damage until ready to receive paving.

D. Tack Coat: Apply uniformly to surfaces of existing pavement at a rate of 0.05 to 0.15 gal./sq.

yd..

1. Allow tack coat to cure undisturbed before applying hot-mix asphalt paving.

2. Avoid smearing or staining adjoining surfaces, appurtenances, and surroundings.

Remove spillages and clean affected surfaces.

3.6 PAVING GEOTEXTILE INSTALLATION

A. Apply tack coat uniformly to existing pavement surfaces at a rate of 0.20 to 0.30 gal./sq. yd..

B. Place paving geotextile promptly according to manufacturer's written instructions. Broom or roll geotextile smooth and free of wrinkles and folds. Overlap longitudinal joints 4 inches and transverse joints 6 inches.

1. Protect paving geotextile from traffic and other damage and place hot-mix asphalt paving overlay the same day.

3.7 HOT-MIX ASPHALT PLACING

A. Machine place hot-mix asphalt on prepared surface, spread uniformly, and strike off. Place asphalt mix by hand to areas inaccessible to equipment in a manner that prevents segregation of mix. Place each course to required grade, cross section, and thickness when compacted.

1. Place hot-mix asphalt base course in number of lifts and thicknesses indicated.

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2. Place hot-mix asphalt surface course in single lift.

3. Spread mix at minimum temperature of 250 deg F.

4. Begin applying mix along centerline of crown for crowned sections and on high side of one-way slopes unless otherwise indicated.

5. Regulate paver machine speed to obtain smooth, continuous surface free of pulls and tears in asphalt-paving mat.

B. Place paving in consecutive strips not less than 10 feet wide unless infill edge strips of a lesser width are required.

1. After first strip has been placed and rolled, place succeeding strips and extend rolling to overlap previous strips. Complete a section of asphalt base course before placing asphalt surface course.

C. Promptly correct surface irregularities in paving course behind paver. Use suitable hand tools to remove excess material forming high spots. Fill depressions with hot-mix asphalt to prevent segregation of mix; use suitable hand tools to smooth surface.

3.8 JOINTS

A. Construct joints to ensure a continuous bond between adjoining paving sections. Construct joints free of depressions, with same texture and smoothness as other sections of hot-mix asphalt course.

1. Clean contact surfaces and apply tack coat to joints.

2. Offset longitudinal joints, in successive courses, a minimum of 6 inches.

3. Offset transverse joints, in successive courses, a minimum of 24 inches.

4. Construct transverse joints at each point where paver ends a day's work and resumes work at a subsequent time. Construct these joints using either "bulkhead" or "papered" method according to AI MS-22, for both "Ending a Lane" and "Resumption of Paving Operations."

5. Compact joints as soon as hot-mix asphalt will bear roller weight without excessive displacement.

6. Compact asphalt at joints to a density within 2 percent of specified course density.

3.9 COMPACTION

A. General: Begin compaction as soon as placed hot-mix paving will bear roller weight without excessive displacement. Compact hot-mix paving with hot, hand tampers or with vibratory-plate compactors in areas inaccessible to rollers.

1. Complete compaction before mix temperature cools to 185 deg F.

B. Breakdown Rolling: Complete breakdown or initial rolling immediately after rolling joints and outside edge. Examine surface immediately after breakdown rolling for indicated crown, grade, and smoothness. Correct laydown and rolling operations to comply with requirements.

C. Intermediate Rolling: Begin intermediate rolling immediately after breakdown rolling while hot-mix asphalt is still hot enough to achieve specified density. Continue rolling until hot-mix asphalt course has been uniformly compacted to the following density:

1. Average Density: 96 percent of reference laboratory density according to ASTM D 6927 or AASHTO T 245, but not less than 94 percent nor greater than 100 percent.

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D. Finish Rolling: Finish roll paved surfaces to remove roller marks while hot-mix asphalt is still warm.

E. Edge Shaping: While surface is being compacted and finished, trim edges of pavement to proper alignment. Bevel edges while asphalt is still hot; compact thoroughly.

F. Repairs: Remove paved areas that are defective or contaminated with foreign materials and replace with fresh, hot-mix asphalt. Compact by rolling to specified density and surface smoothness.

G. Protection: After final rolling, do not permit vehicular traffic on pavement until it has cooled and hardened.

H. Erect barricades to protect paving from traffic until mixture has cooled enough not to become marked.

3.10 INSTALLATION TOLERANCES

A. Pavement Thickness: Compact each course to produce the thickness indicated within the following tolerances:

1. Base Course: Plus or minus 1/2 inch.

2. Surface Course: Plus 1/4 inch, no minus.

B. Pavement Surface Smoothness: Compact each course to produce a surface smoothness within the following tolerances as determined by using a 10-foot straightedge applied transversely or longitudinally to paved areas:

1. Base Course: 1/4 inch.

2. Surface Course: 1/8 inch.

3. Crowned Surfaces: Test with crowned template centered and at right angle to crown.

Maximum allowable variance from template is 1/4 inch.

3.11 SURFACE TREATMENTS

A. Fog Seals: Apply fog seal at a rate of 0.10 to 0.15 gal./sq. yd. to existing asphalt pavement and allow to cure. With fine sand, lightly dust areas receiving excess fog seal.

B. Slurry Seals: Apply slurry coat in a uniform thickness according to ASTM D 3910 and allow to cure.

1. Roll slurry seal to remove ridges and provide a uniform, smooth surface.

3.12 PAVEMENT MARKING

A. Do not apply pavement-marking paint until layout, colors, and placement have been verified with Architect.

B. Allow paving to age for 30 days before starting pavement marking.

C. Sweep and clean surface to eliminate loose material and dust.

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D. Apply paint with mechanical equipment to produce pavement markings, of dimensions indicated, with uniform, straight edges. Apply at manufacturer's recommended rates to provide a minimum wet film thickness of 15 mils.

1. Broadcast glass beads uniformly into wet pavement markings at a rate of 6 lb/gal..

3.13 FIELD QUALITY CONTROL

A. Testing Agency: Engage a qualified testing agency to perform tests and inspections.

B. Thickness: In-place compacted thickness of hot-mix asphalt courses will be determined according to ASTM D 3549.

C. Surface Smoothness: Finished surface of each hot-mix asphalt course will be tested for compliance with smoothness tolerances.

D. In-Place Density: Testing agency will take samples of uncompacted paving mixtures and compacted pavement according to ASTM D 979 or AASHTO T 168.

1. Reference maximum theoretical density will be determined by averaging results from four samples of hot-mix asphalt-paving mixture delivered daily to site, prepared according to ASTM D 2041, and compacted according to job-mix specifications.

2. In-place density of compacted pavement will be determined by testing core samples according to ASTM D 1188 or ASTM D 2726.

a. One core sample will be taken for every 1000 sq. yd. or less of installed pavement, with no fewer than 3 cores taken.

b. Field density of in-place compacted pavement may also be determined by nuclear method according to ASTM D 2950 and correlated with ASTM D 1188 or

ASTM D 2726.

E. Replace and compact hot-mix asphalt where core tests were taken.

F. Remove and replace or install additional hot-mix asphalt where test results or measurements indicate that it does not comply with specified requirements.

3.14 DISPOSAL

A. Except for material indicated to be recycled, remove excavated materials from Project site and legally dispose of them in an EPA-approved landfill.

1. Do not allow milled materials to accumulate on-site.

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SECTION 32 93 00 – SITE RESTORATION AND REVEGETATION

PART 1 - GENERAL

1.1 PROJECT SPECIFIC REQUIREMENTS

A. General: Re-vegetate all areas indicated along with all disturbed areas in accordance with the requirements of this specification section.

B. Steep Slopes: In areas with slopes greater than 3%, restore the disturbed area by seeding at three times the rate recommended by the Overarching Environmental Specifications, adding erosion blankets, and applying hydromulch. Where slopes are greater than 8%, build soil berms the full width of the utility corridor spaced 35 feet apart. The axis of each berm shall be approximately 75 degrees off from the axis of the corridor. Alternating berms shall slope in opposite directions.

1.2 PLANT MATERIALS FOR REVEGETATION

A. NATIVE SEED. Depending on the site conditions, one of the following native seed mixes shall be used for revegetating most disturbed areas. Other seed mixes may need to be developed for unique areas on a case-by-case basis. Any modification of the specified seed mixes shall be coordinated with USAFA Natural Resources (10 CES/CECN, 333-3308). All seed mixes shall consist of certified seed varieties that are free of noxious weeds and have been tested for purity and germination within six months of the planting date. Locally adapted seed ecotypes collected from a similar elevation (6300-8000’ at USAFA; 9000’ at Farish Recreation Area) and precipitation zone (15-20 inches) shall be used. The pounds of Pure Live Seed (PLS) per acre specified below are for drill seeding only. If the seed is to be broadcast by hand, spreader or hydro-seeder the seeding rate shall be doubled.

1. Xeric (dry) areas with a variety of soil and slope conditions shall be planted with the following seed mix:

SPECIES (Variety) II. PLS RATE PER ACRE Little Bluestem (Camper) Schi-zachyrium scoparium

3.0

Blue Grama (Hachita) Boute-loua gracilis

1.5

Side Oats Grama (Vaughn) Bouteloua curtipendula

3.5

Green Needlegrass Stipa viridula

0.5

Sand Dropseed Sporobolus cryptandrus

0.05

Western Wheatgrass (Arriba) Pascopyrum smithii

3.0

Slender Wheatgrass (San Luis) Elymus trachycaulus

1.0

2. Mesic (moist) areas shall be planted with the following seed mix:

SPECIES (Variety) PLS RATE PER ACRE

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Switchgrass (Forrestburg) Pa-nicum virgatum

2.5

Western Wheatgrass (Arriba)

2.0

Canada Wildrye (Mandan) Ely-mus canadensis

4.5

Slender Wheatgrass (San Luis) Elymus trachycaulus

Canadian reed-grass Calama-grostis canadensis

0.25

Streambank wheatgrass (So-dar) Elymus lanceolatus

3. Wetland areas shall be planted with 2.5” containerized live plugs on 18” centers and seeded with the grasses identified below. Locally adapted plugs shall be planted flush with the ground surface and rooted in moist to saturated soil depending on the species’ moisture regime preference. The quantity of plugs needed, by species, shall be based on the planting percentages listed in the table below.

Canadian reed-grass Calama-grostis canadensis

0.25

Ticklegrass Agrostis scabra

0.2

Nebraska sedge Carex canadensis

Plugs – 70%

Creeping spikerush Eleocharis palustris

Plugs – 10%

Torrey’s rush Juncus torreyi

Plugs – 5%

Baltic rush Juncus balticus

Plugs – 10%

Pale bulrush Scirpus pallidus

Plugs – 5%

4. Upland areas at Farish Recreation Area, with a wide variety of slope and soil conditions, shall be planted with the following seed mix:

Mountain Muhly Muhlenbergia montana

0.5

Arizona fescue (Redondo) Fes-tuca arizonica

Western wheatgrass (Arriba)

2.5

Sideoats grama (Vaughn) Bouteloua curtipendula

Thickspike wheatgrass (Crita-na) Elymus lanceolatus

Idaho fescue (Winchester) Festuca idahoensis

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5. As directed by USAFA Natural Resources, perennial ryegrass shall be added to the xeric, mesic, and Farish seed mixes, but the PLS seeding rate of the native plants shall remain unchanged.

Perennial Ryegrass (Tetraploid) Lolium perenne

6.0

1.3 SITE PREPARATION

A. SOIL PREPARATION. All disturbed areas shall be tilled to a minimum depth of four inches, then harrowed or raked to produce a firm seed bed for planting. Large rocks (>6 inch diameter) and other debris shall be cleared from the site. Any necessary erosion control structures (e.g., water bars, berms, turnouts) shall be constructed prior to seeding. No fertilizers shall be applied to any seeded area.

B. TOPSOIL. Where possible, native topsoil shall be salvaged prior to construction and stockpiled for later redistribution over the disturbed areas. Disturbed sites that have unsuitable surface soils (sandy, rocky, clayey) for plant growth shall be covered with 3-inches of a weed-free, loamy topsoil (i.e., high organic matter content, non-compacted structure) that is free of rocks, large woody debris, trash, or other non-soil materials. All topsoil shall be incorporated by disking it into the subsoil. Suitable topsoil material may be available from the Academy’s mulch yard, but access to this material must be coordinated with the yard manager and the material must be approved by USAFA Natural Resources.

1.4 SEEDING AND MULCHING

A. SEEDING DATES. Site stabilization and seeding shall normally occur within 14 days of the completion of a project or project phase. Depending on the project schedule, seeding shall be conducted during the fall (September-November) or spring (March-May) to maximize planting success. If the project schedule does not correspond with the preferred seeding periods, then Best Management Practices shall be implemented to stabilize the disturbed area until the next appropriate seeding period. Any proposed seeding dates that fall outside the preferred months shall require Government approval and coordination with the USAFA Natural Resources office.

B. SEEDING METHODS. Drill seeding or broadcast seeding shall be used depending on the slope of the disturbed site and the size of the area. Where feasible, drill seeding and crimped hay mulching or hydro-mulching is the required method of revegetation.

1. Slopes less than 3:1 – Seed shall be drilled using a rangeland drill with a small seed/legume box and an agitator box for fluffy or bulky seed. Seed rows shall be spaced 7-10 inches apart, and planted 0.5 to 0.75 inches deep. The drill shall have double-disk furrow openers with depth bands and packer wheels. Seeding shall be accomplished using bi-directional drilling and following the slope contour. The seed drill shall be calibrated each day or whenever there is a change in seed mixes to ensure adequate seed distribution.

2. Slopes greater than 3:1 or areas less than 0.10 acre – Seed shall be broadcast by hand, mechanical spreader, or hydro-seeding equipment. Broadcast seeded areas shall be raked or harrowed to incorporate the seed into the soil at a depth not exceeding 0.75 inches. If hydro-seeding is used, the seed shall not be tank mixed with the hydro-mulch and broadcast.

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C. MULCHING. Weed-free native hay, weed-free straw, virgin wood fiber hydro-mulch, erosion control blankets, and/or coir logs shall be used to control erosion and promote seed germination and plant establishment. Native hay, straw, or hydro-mulch shall be applied at 2000 pounds/acre on slopes less than 3:1. On steeper slopes, a hydro-mulching rate of 2500 pounds/acre shall be used. Native hay or straw shall be crimped into the soil to a depth of 3-4 inches, and shall protrude above the ground 3-4 inches. An organic tackifier shall be used to hold the hay or straw in place if the crimping results are insufficient. Hydro-mulch shall be applied using a color dye and the manufacturer recommended rate of an organic tackifier.

Erosion control blankets, soil berms, and/or straw wattles shall be used whenever reclaiming slopes greater than 3:1 or along drainage areas where erosion is probable. All erosion control materials shall be net-free or constructed with biodegradable double-netting or jute netting.

Manufactured biodegradable stakes or wooden stakes shall normally be used to anchor any erosion materials, but metal staples may be approved on a case-by-case basis. All erosion control materials shall be installed in accordance with the manufacturer’s instructions and recommendations.

D. WEED CONTROL. If weed growth is limiting stand establishment the site shall be mowed 2-3 times per year at a height just above the planted grasses. Broadleaf herbicides may also be used to control weed growth as long as damage to the grass seedlings does not occur.

E. WATERING. Artificial watering will normally not be required (or necessary) if the seeding is accomplished during the preferred planting periods. However, where access to potable or non-potable water is available, a sprinkler system may be desirable to enhance plant establishment.

Generally, watering at 0.75-1.0 inches/week is recommended during the growing season.

Using water trucks to irrigate is generally not recommended due to traffic impacts on the seeded areas and inadequate water infiltration.

1.5 RESEEDING

A. A successful revegetation project shall have at least 3 planted native grass seedlings/square foot (not including weedy species) and no bare areas exceeding one square meter after the second growing season. If a partial or total seeding failure is apparent after the second growing season, poorly vegetated areas shall be reseeded in the same manner described above.

Appropriate site preparation practices shall be used to create a suitable seedbed for planting, but any established native vegetation shall be undisturbed to the extent possible. Areas that erode before germination and establishment can occur shall be repaired and immediately reseeded during the same season.

1.6 TREE CARE DURING CONSTRUCTION

A. Extreme care shall be exercised in protecting branches and root systems of existing trees. To the extent possible, moist conditions shall be maintained during construction. Roots damaged during excavation shall be pruned. Branch removal shall be minimized, with necessary removal done following standard pruning techniques (no flush cuts – as these increase tree decay in proximity to the pruning wound, etc).

B. Contact Natural Resources (10 CES/CECN 333-3308) for technical advice on pruning techniques.

C. See Appendix A for additional information on proper pruning techniques.

D. Information on protecting trees during construction activities can be found at www.ext.colostate.edu/PUBS/GARDEN/07420.html http://www.ext.colostate.edu/PUBS/GARDEN/07420.html

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1.7 TREE TRANSPLANTING FROM CONSTRUCTION AREA

A. Whenever possible, existing trees that need to be cleared shall be relocated or sold by Natural Resources as a forest product prior to site clearing. Transplantable trees are generally less than 25’ in height. Coordinate with Natural Resources at least two months in advance to assess the feasibility of transplanting trees.

1.8 CARE OF TREES MOVED INTO CONSTRUCTION AREA

A. Trees moved into project area for landscaping purposes shall have irrigation needs addressed for at least two years, including winter watering. Approximately 10 gallons per inch of tree caliper (measured at 6” above ground level) shall be applied to the tree ring area upon planting.

A similar amount should be applied weekly throughout the first growing season (as frequently as twice weekly for the first several weeks in dry and windy conditions), depending on natural moisture and soil conditions. Light watering applications (i.e. sprinklers) will not provide adequate water saturation, as this will tend to promote root proliferation within the top several inches of soil, rather than encouraging deeper root establishment which is vital to long-term survival. The objective of this periodic deep watering is to saturate the root ball to a depth of at least 12”. Water amounts on heavy clay soils with poor drainage may need to be lessened to avoid drowning the root system. A rule of thumb would be to check the edge of the root ball for moisture at a depth of 4-6”. If this area is still moist, watering can be postponed.

B. Winter watering from late October through March is critical, especially in dry climates with desiccating winter winds. Water should be applied monthly during dry periods, when the ground is not frozen. As the tree becomes established, the need for supplemental watering should decrease. This watering regime should be implemented for at least the first two seasons to assist in establishment, but is advisable beyond this timeframe if the transplanted tree is especially large, or is slow in adapting to its new site.

C. A soil berm or tree ring of at least 4” height shall be constructed around the tree (roughly under the tree dripline (outer edge of branches), or at least the size of the transplanted root ball). This will allow water to focus onto the root ball. The berm should be removed within two to three years.

D. Approximately 2-3” of mulch shall be placed above the root ball to preserve soil moisture, and to protect trees from lawnmower damage in mowed areas. Mulch should not be placed directly against tree stem, as this could cause rotting of wood, and could afford rodents a place to hide and potentially damage tree. A distance of at least 6” from tree stem should be left unmulched.

E. Transplanted trees shall be sprayed to prevent bark beetle infestation (with a persistent formulation of active ingredients Carbaryl or Permethrin) within one week of transplanting, and one additional time late in the growing season. Transplanted trees are a prime target for the Ips (Pine engraver) beetle, which are attracted to stressed trees.

F. In general, trees over 6’ in height shall be staked, unless they are not located in a wind-prone location (i.e. sheltered from predominant west/north winds by a building), or do not have a large crown. Stakes shall be removed in one year, unless in unusually windy location, in which case they should be removed after the second growing season. Retaining stakes for too long compromises windfirmness.

G. Trees should not be fertilized upon transplanting, as this encourages stem growth at the expense of root growth. Root growth is more critical at this time, so fertilization (nitrogen in particular) is best held off for several years. A root stimulant (generally high in phosphorus) may be used during or immediately after transplanting.

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H. Coordinate with Natural Resources to advise on watering, mulching, spraying, staking, and fertilization.

I. Holes resulting from trees moved from elsewhere on the Academy must be filled within one week

J. See Appendix B for additional information and guidelines on watering guidelines.

1.9 FIREWOOD AND SLASH REMOVAL

A. Trees needing removal that are deemed infeasible for transplanting shall be cut and limbed (all limbs removed). Firewood (tree stems and limbs >3” in diameter) shall be delivered to the NR woodlot, with slash delivered to the 10 CES compost yard. Contractor may opt to purchase firewood at the published rate whenever possible (currently $10 per cord). Coordinate wood delivery or purchase with Natural Resources.

1.10 BEETLE-INFESTED TREES

A. Trees infested with mountain pine beetle shall be chipped, debarked, or removed from site to be processed before beetles emerge in early July. If removed from site and not processed in a mill, infested wood should not be placed within five miles of any pines, to prevent beetle spread to other areas. Beetle-infested wood shall not be delivered to NR woodlot unless debarked.

Coordinate with Natural Resources for site visit to check for beetle infestation.

1.11 CONE COLLECTION

A. If feasible, Natural Resources requests the opportunity to collect cones from high quality trees that must be cut during site clearing. A Natural Resources representative will assess this opportunity, and will coordinate with project manager on timing feasibility. Cones ripen in September. Natural Resources would fell trees for collection upon ripening, if this does not hinder construction progress. Seed from cones would be utilized to grow tree seedlings for future reforestation needs on the Academy.

PART 2 - PRODUCTS

2.1 RECOMMENDED PLANT LIST

A. US Air Force Academy (Last Revision – July 12, 2004)

1. There are numerous native species that could be planted on the Academy for habitat restoration projects and revegetation in natural areas; the following are some of the more common species that may be readily available from seed suppliers and plant nurseries.

Grasses Andropogon gerardii Big bluestem Bouteloua curtipendula Sideoats grama Calamovilfa longifolia Prairie sandreed Chondrosum gracile Blue grama Elymus canadensis Canada wildrye Festuca pratensis Meadow fescue Koeleria macrantha Mountain muhly

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Oryzopsis hymenoides Indian ricegrass Pascopyrum smithii Western wheatgrass Schizachyrium scoparium Little bluestem Sporobolus cryptandrus Sand dropseed Stipa comata Needle-and-thread Stipa viridula Green needlegrass Panicum virgatum Switchgrass Sorgastrum nutans Yellow Indian grass Juncus balticus Baltic rush Juncus torreyi Torrey rush Carex nebrascensis Nebraska sedge

Forbs Asclepias speciosa Showy milkweed Liatris punctata Gay feather Ratibida columnifera Prairie cone flower Rudbeckia hirta Black-eyed Susan Lupinus argenteus Common lupine Plantago major Common plantain Plantago patagonica Wooly plantain Penstemon species Penstemon

Shrubs Cercocarpus montanus Mountain mahogany Crataegus erythropoda Hawthorn Holodiscus dumosus Ocean spray Padus virginiana Choke cherry Pentaphylloides floribunda Shrubby cinquefoil Physocarpus monogynus Ninebark Potentilla fruticosa Shrubby cinquefoil Prunus Americana Wild plum Rosa woodsii Wild Rose Ribes aureum Golden currant Ribes cereum Wax currant Ribes inerme Gooseberry Ribes americanum Wild black currant Rhus aromatica Skunkbush Rhus glabra Smooth sumac Symphoricarpos albus Snowberry Krascheninnikovia lanata Winter fat Chrysothamnus nauseosus Rubber rabbitbrush Salix exigua Sandbar willow Artemisia frigida Fringed sage Quercus gambelii Gambel’s oak Shepherdia canadensis Buffalo-berry

PART 3 - EXECUTION (Not Applicable)

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APPENDIX A – PRUNING TECHNIQUES

Pruning Cuts

Pruning cuts should be made so that only branch tissue is removed and stem tissue is not dam-aged. At the point where the branch attaches to the stem, branch and stem tissues remain sepa-rate, but are contiguous. If only branch tissues are cut when pruning, the stem tissues of the tree will probably not become decayed, and the wound will seal more effectively.

1. Pruning living branches (Fig. 6)

To find the proper place to cut a branch, look for the branch collar that grows from the stem tissue at the underside of the base of the branch (Fig. 6A). On the upper surface, there is usually a branch bark ridge that runs (more or less) parallel to the branch angle, along the stem of the tree. A proper pruning cut does not damage either the branch bark ridge or the branch collar.

Figure 6A. Targeting the cut

A proper cut begins just outside the branch bark ridge and angles down away from the stem of the tree, avoiding injury to the branch collar (Fig. 6B). Make the cut as close as possible to the stem in the branch axil, but outside the branch bark ridge, so that stem tissue is not injured and the wound can seal in the shortest time possible. If the cut is too far from the stem, leaving a branch stub, the branch tissue usually dies and woundwood forms from the stem tissue. Wound closure is delayed because the woundwood must seal over the stub that was left.

1.1. The quality of pruning cuts can be evaluated by examining pruning wounds after one grow-ing season. A concentric ring of woundwood will form from proper pruning cuts (Fig. 6B).

Flush cuts made inside the branch bark ridge or branch collar, result in pronounced devel-opment of woundwood on the sides of the pruning wounds with very little woundwood form-ing on the top or bottom (Fig. 7D). As described above, stub cuts result in the death of the remaining branch and woundwood forms around the base from stem tissues.

1.2. When pruning small branches with hand pruners, make sure the tools are sharp enough to cut the branches cleanly without tearing. Branches large enough to require saws should be supported with one hand while the cuts are made. If the branch is too large to support, make a three-step pruning cut to prevent bark ripping (Fig. 6C).

http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun022.htm http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun023.htm http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun023.htm http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun024.htm http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun025.htm

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1. The first cut is a shallow notch made on the underside of the branch, outside the branch collar.

This cut will prevent a falling branch from tearing the stem tissue as it pulls away from the tree.

2. The second cut should be outside the first cut, all the way through the branch, leaving a short stub.

3. The stub is then cut just outside the branch bark ridge/branch collar, completing the operation.

2. Pruning dead branches (Fig. 6)

Prune dead branches in much the same way as live branches. Making the correct cut is usually easy because the branch collar and the branch bark ridge can be distinguished from the dead branch be-cause they continue to grow (Fig. 6A). Make the pruning cut just outside of the ring of woundwood tissue that has formed, being careful not to cause unnecessary injury (Fig. 6C). Large dead branches should be supported with one hand or cut with the three-step method, just as live branches. Cutting large living branches with the three step method is more critical because of the greater likelihood of bark ripping.

(Appendix A is from a U.S. Forest Service publication)

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APPENDIX B –TREE CARE FOLLOWING PLANTING

After planting the tree, build a 4-inch tall berm around the edge of the hole. Fill the berm with mulch (i.e.

shredded bark, compost). The mulch and berm make it easier to water the tree and reduce weed compe-tition. Below are diagrams of a typical tree planting.

Right after planting, water the tree in by filling the bermed basin with water. This will settle the existing soil around the root ball. Fill the bermed basin with water once a week during the growing season, unless natural precipitation is abundant. The goal is to wean the tree slowly off of supplemental irrigation, and get the root system large enough for the tree to thrive on natural rainfall. Continue with winter watering once a month during extended dry periods from late October through March, unless ground is frozen.

REMEMBER: These are just guidelines. Use your index finger to check the soil moisture under the mulch.

More plants are killed by over-watering than by under-watering.

(Portions of this appendix are from Douglas F. Welsh, Landscape Horticulturist Texas A&M University, College Station, Texas).

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B. Pavement-Marking Paint: Proceed with pavement marking only on clean, dry surfaces and at a minimum ambient or surface temperature of 40 deg F for oil-based materials, and not exceeding 95 deg F.

D. Mineral Filler: ASTM D 242 or AASHTO M 17, rock or slag dust, hydraulic cement, or other inert material.

G. Glass Beads: AASHTO M 247, Type 1.