GSA 015639TreePlantProtectionFY15UpdateOct.12014.docx.pdf

Greenville, SC Courthouse Project Greenville, South Carolina Solicitation No. GS-04-P-16-BV-C-7005

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 1

SECTION 015639 - TREE AND PLANT PROTECTION

1.1 SUMMARY

A. Section includes general protection and pruning of existing trees and plants that are affected by execution of the Work, whether temporary or permanent construction.

1.2 DEFINITIONS

A. Protection Zone: Area surrounding individual trees, groups of trees, shrubs, or other vegetation to be protected during construction, and indicated on Drawings. For trees, the locations of all Critical Root Zones (CRZs) are defined as the area for each tree which contains the estimated minimal amount of both structural and feeder roots that must be protected to minimize tree damage and retain structural stability.

The CRZ for each tree is calculated based on the Tree Species Tolerance to construction impacts and age class, as outlined in the International Society of Arboriculture’s Best Management Practices:

Managing Trees During Construction (K. Fite, T. Smiley, 2008). Although CRZs will differ by species and tree age, zones range from ½ foot per one inch DBH (diameter at breast height) to 1½ foot per one inch DBH. For example: two foot (2)' DBH tree specie deemed non-sensitive would have a 12' protection zone. A 2' DBH tree specie deemed sensitive would have a 36' protection zone. Sensitivity is determined by species and as such protection requirements are outlined in the 'International Society of Aboricultures Best Management Practices: Managing Trees During Construction' (K. Fite, T. Smiley, 2008) If the species tolerance is unknown, then the 1½ foot per one inch DBH standard is assumed. Mixed groupings of trees will base the required area of protection on that area which is required for maintaining the health of the most sensitive individual species composing the cluster. GSA will assume the 1½ foot standard applies unless sufficient information detailing the contrary is provided. For large shrubs and groups of shrubs a protection area shall be provided equivalent to 1.5 times the diameter of the massing itself, unless otherwise indicated.

1.3 ACTION SUBMITTALS

A. Product Data: For each type of product indicated. [GSA PM, COR or A/E: Coordinate with Contract Drawings.]

B. Samples: For each type of product such as organic mulch in sealed plastic bags labeled with composition of materials by percentage of weight, or material data sheets when truck measured, protection-zone range/snow fencing, root zone plywood protection, and protection-zone signage.

C. Tree Pruning Schedule: Written schedule detailing scope and extent of pruning of trees to remain that interfere with or are affected by construction. This detailed schedule shall identify both limb and root pruning activities and be provided to GSA representative 30-60 days prior to proposed activities.

D. [GSA PM, COR or A/E a survey in the design phase or art in architecture scope of work should require this: Make your documents & specs quantifiable] A Certified Arborist Report (CAR) should be prepared and submitted to the GSA along with the topographic survey that clearly demonstrates the size, species, and condition of all existing trees and shrubbery on site.

Detailed plans should be provided for those plants that will be impacted/removed.. This includes identifying proposed new tree locations and quantities, as well as the protection plan for existing trees during the construction activity. All proposed grade changes affecting the protected site

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 2 trees should be identified. Further this report should document existing conditions of trees and plantings indicated to remain, which establishes preconstruction conditions that might later be misconstrued as damage caused by construction activities.

E. Certification: From arborist, certifying that trees indicated in the above Certified Arborist Report have in fact been protected and properly prepared for construction according to recognized standards and that trees were promptly and properly treated and repaired if damaged.

1.4 INFORMATIONAL SUBMITTALS

A. Maintenance Recommendations: From arborist, for care and protection of trees affected by construction during and after completing the Work.

1.5 QUALITY ASSURANCE

A. Arborist Qualifications: Certified Arborist as certified by ISA, licensed arborist in jurisdiction where Project is located, current member of ASCA, or registered Consulting Arborist as designated by

ASCA.

B. Preconstruction Conference: Include as part of the project’s overall preconstruction conference.

1.6 PROJECT CONDITIONS [GSA PM, COR or A/E: Coordinate with staging & logistics contract drawings.]

A. The following practices are prohibited within protection zones:

1. Storage of construction materials, debris, or excavated material.

2. Parking vehicles or equipment.

3. Foot traffic.

4. Erection of sheds or structures.

5. Impoundment of water.

6. Excavation or other digging unless otherwise indicated.

7. Attachment of signs to or wrapping materials around trees or plants unless otherwise indicated.

B. Do not direct vehicle or equipment exhaust toward protection zones.

C. Prohibit heat sources, flames, ignition sources, and smoking within or near protection zones and organic mulch.

PART 2 - PRODUCTS

2.1 MATERIALS

A. Topsoil: Natural or cultivated top layer of the soil profile or manufactured topsoil; containing organic matter and sand, silt, and clay particles; friable, pervious, and black or a darker shade of brown, gray, or red than underlying subsoil; reasonably free of subsoil, clay lumps, gravel, and

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 3 other objects more than ½” in diameter; and free of weeds, roots, and toxic and other non-soil materials.

B. Topsoil: Stockpiled topsoil from location shown on Drawings.

C. Organic Mulch: Shredded hardwood, shredded bark, wood and bark chips, pine needle mulch, free from deleterious materials.

D. Protection-Zone Fencing: Fencing fixed in position and meeting one of the following requirements. Previously used materials may be used when inspected for condition and approved in writing by resident engineer.

Retain one or more of first five subparagraphs below for protection-zone fencing to suit Project; coordinate with details shown on Drawings. Insert requirements for paint and color if required.

1. Chain-Link Protection-Zone Fencing: Galvanized-steel fencing fabricated from minimum 1-inch opening, 0.148-inch- diameter wire chain-link fabric; with pipe posts, minimum 2-3/8-inch- OD line posts, and 2-7/8-inch- OD corner and pull posts; with 1-5/8-inch- OD top rails and 0.177-inch- diameter bottom tension wire; with tie wires, hog ring ties, and other accessories for a complete fence system.

2. Plywood Protection-Zone Fencing: Plywood framed with four 2-by-4-inch rails, with 4-by-4-inch preservative-treated wood posts spaced not more than 8 feet apart.

3. Wood Protection-Zone Fencing: Constructed of two 2-by-4-inch horizontal rails, with 4-by-4-inch preservative-treated wood posts spaced not more than 8 feet apart, and lower rail set halfway between top rail and ground.

4. Plastic/Snow Protection-Zone Fencing: Plastic construction fencing constructed of high-density extruded and stretched polyethylene fabric with 2-inch maximum opening in pattern and supported by tubular or T-shape galvanized-steel posts spaced not more than 8 feet apart. High-visibility orange color, non-fading.

5. Height of Fencing: Protective fencing should range between four feet (4’) and eight feet-(8’) in height. The specific height of each area of protection should be indicated on the Certified Arborist Report with justification.

6. Gates: Swing access gates matching material and appearance of fencing, to allow for maintenance activities within protection zones.

E. Protection-Zone Signage: Shop-fabricated, rigid plastic or metal sheet with attachment holes pre-punched and reinforced; legibly printed with non-fading lettering.

PART 3 - EXECUTION

3.1 EXAMINATION AND PREPARATION

A. contracted Construction Manager (CM) on site) shall examine the site to verify that temporary erosion- and sedimentation-control measures are in place. Verify that flows of water redirected from construction areas or generated by construction activity do not enter or cross protection zones.

B. The GSA on site representative (i.e. GSA PM, COR or CM on site) shall notify in writing contractor to protect tree root systems from damage caused by runoff or spillage of noxious materials while mixing, placing, or storing construction materials. Protect root systems from ponding, eroding, or excessive wetting caused by dewatering operations.

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 4

C. Protection Zones: Contractor shall mulch areas inside protection zones and other areas as indicated in the Certified Arborist Report with a four inch (4”) to six inch (6”” average thickness of organic mulch. No mulch shall be placed within six inches (6”) of tree trunks.

3.2 ESTABLISHING PROTECTION ZONES

A. Protection-Zone Fencing: Install protection-zone fencing along edges of protection zones in a manner that will prevent people from easily entering protected area except by entrance gates.

1. Chain-Link Fencing: Install to comply with ASTM F 567 and with manufacturer's written instructions.

2. Posts: Set or drive posts into ground one-third the total height of the fence without concrete footings. Where a post is located on existing paving or concrete to remain, provide appropriate means of post support acceptable to resident engineer.

3. Access Gates: Install where indicated on drawing/Certified Arborist Report.

B. Protection-Zone Signage: Install protection-zone signage in visibly prominent locations in a manner approved by the GSA on site representative (i.e. GSA PM, COR or CM on site) .

C. Maintain protection-zone fencing and signage in good condition as acceptable to the GSA Contracting Officer (CO) and remove when construction operations are complete and equipment has been removed from the site.

3.3 CONSTRUCTION ACTIVITIES WITHIN CRITICAL ROOT ZONES

A. In general no encroachment within the CRZ shall occur without the written permission of the GSA CO. The fieldwork shall not occur without the on-site presence of the Agency’s representative or an approved arborist. If encroachment is permitted, the following preventative measures shall be employed:

1. Soil protection: To mitigate soil compaction the CRZ must first be mulched with a minimum six (6) inch layer of mulch and/or plywood sheeting, as specified by the Agency/Arborist.

Mulch should be maintained during the course of construction and carefully removed thereafter.

2. Removal of existing infrastructure: Extreme care must be exercised in removing concrete or asphalt with the CRZ. All removal shall favor lifting as opposed to dragging.

3. Methods of excavation: Any excavation required for utility or infrastructure installation within a CRZ or elsewhere on the site as designated by the Agency shall be done by hand or pneumatic excavation, or micro tunneling. Trenching shall not occur within the CRZ unless absolutely necessary and without prior agreement of the licensed GSA landscape professional or Arborist.

4. Treatment of exposed roots: Where such excavation does occur for the removal of existing features or the installation of new work, the excavated area shall be backfilled immediately.

Exposed roots shall be covered with burlap or other approved material, and kept constantly moist. Burlap shall be checked a minimum of two (2) times a day, once in the morning and once in the afternoon in order to maintain appropriate levels of moisture, until backfill is complete. If directed by the GSA CO, soaker hoses shall be installed to facilitate properly moist conditions of excavated areas.

5. Grade reduction: Many tree roots occur within the top six to eight inches of the soil. Soil removal can result in the loss of tree roots. Soil removal within the tree protection zone is

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 5 prohibited without the written approval of the GSA CO. Soil removal methods are to be determined by the Agency/arborist. Any proposed removal of soil, and supervision of the removal, within the CRZ shall be performed under the supervision of an independent Consulting Arborist.

6. Grade Increase: The addition of soil can smother tree roots, by reducing the amount of water and oxygen reaching the soil area where tree roots occur. Fill up to three (3) inches additional depth may be permitted. A specific submission should be made to the GSA CO. Fill exceeding three (3) inches shall not occur without the prior installation of an aeration system or other detail such as tree well, retaining wall, or other similar feature and approved by a licensed GSA landscape professional/certified arborist. Planting beds that are installed within tree protection zones can only be done by hand, with minimal soil disturbance. No roots over 1-inch in diameter shall be cut. Plants shall not be placed within three (3) feet of the tree trunk.

7. Root Pruning: Clear and excavate by hand to the depth of the required excavation to minimize damage to root systems. Use narrow-tine spading forks, comb soil to expose roots, and cleanly cut roots as close to excavation as possible. Cut roots manually by digging a trench and cutting exposed roots with sharp pruning instruments; do not break, tear, chop, or slant the cuts. Do not use a backhoe or other equipment that rips, tears, or pulls roots.

3.4 CROWN PRUNING

A. Prune branches that are affected by temporary and permanent construction. Prune branches as indicated in Certified Arborist Report or as identified by arborist in the field.

1. Prune trees to remain to compensate for root loss caused by damaging or cutting root system. Provide subsequent maintenance during Contract period as recommended by arborist.

2. Pruning Standards: Prune trees according to ANSI A300 (Part 1) and the International Society of Arboriculture’s Best Management Practices: Managing Trees During Construction (K. Fite, T. Smiley, 2008).

3. Cut branches with sharp pruning instruments; do not break or chop.

4. Do not apply pruning paint to wounds.

B. Chip the removed branches and stockpile in areas approved by the GSA on site representative (i.e. GSA PM, COR, Building Manager or CM on site).

3.5 FIELD QUALITY CONTROL

A. Inspections: Engage a certified arborist to direct plant-protection measures in the vicinity of trees, shrubs, and other vegetation indicated to remain and to prepare inspection reports.

3.6 REPAIR AND REPLACEMENT

A. General: Repair or replace trees, shrubs, and other vegetation indicated to remain or be relocated that are damaged by construction operations, in a manner approved by the GSA CO.

1. Have arborist perform the root cutting, branch pruning, and damage repair of trees and

FY15 Update Oct. 1, 2014 Tree & Plant Protection 015639 - 6 shrubs.

2. Treat damaged trunks, limbs, and roots according to arborist's written instructions.

3. Perform protection area repairs within 24 hours of incident.

4. Replace vegetation that cannot be repaired and restored to full-growth status, as determined by licensed GSA landscape professional.

3.7 DISPOSAL OF SURPLUS AND WASTE MATERIALS

A. Disposal: Remove excess excavated material, displaced trees, trash and debris associated with this work, and legally dispose of them off Owner's property or as directed by the GSA on site representative (i.e. GSA PM, COR or CM on site) or licensed GSA landscape professional.

END OF SECTION 015639