Section 01 56 39: Temporary Tree and Plant Protection
PART 1: GENERAL
The contractors shall furnish all labor, materials, equipment, and services necessary for the protection of existing trees and vegetation as required and as specified herein.
The plans shall include annotation that indicates it is the responsibility of the General Contractor to repair, replace, or reimburse OSU for any damaged plant material within a Tree Protection Zone.
All landscape materials shall be protected to ensure they are not damaged.
All staging areas located on planting areas shall be covered with woven geotextile fabric and have a minimum six inch mulch bed placed over area prior to any staging of equipment or materials to prevent soil compaction.
All vehicular or motorized equipment access to a staging area over turf shall be covered with woven geotextile fabric with a minimum of six inches of mulch bed placed over the area to prevent the compaction of soil.
The General Contractor is responsible for removing all construction or construction related debris from the project site and adjacent landscape or shrub beds.
The project site survey shall include accurate locations and diameters of existing trees as well as a sufficient number of spot elevations to determine the existing elevation of the tree root zone and root flare.
Tree Root Protection Zone (TRPZ): An area that generally extends from the base of the tree trunk beyond the drip line of the tree.
Drip line: Outer perimeter of branches of any plant.
Project Arborist: A certified arborist with the experience to conduct the required work outlined in this section shall be employed by the university.
University Arborist: A certified arborist employed by or contracted by the university to inspect and oversee the daily construction activities to ensure the program developed by the project arborist is executed according to the tree protection plan.
CALCULATING THE TREE ROOT PROTECTION ZONE
Measure the tree’s diameter at breast height (DBH), in inches. DBH is calculated using the circumference of the tree trunk at 4.5 feet above grade.
Multiply the DBH by 1.5.
Example = 7” DBH x 1.5 = 10.5’.
The result expressed in feet shall be the minimum radius of the TRPZ.
For trees less than 8” in DBH, the TRPZ shall not be less than the diameter of the canopy drip line.
For shrubs scheduled to remain the protection shall be the drip line of the existing plant or plant grouping.
The project arborist will coordinate with other trades and contractors affecting or affected by work of this section to ensure that tree protection measures are understood prior to work commencing.
An on-site review of tree protection measures will be completed among the project arborist, Landscape Architect, contractor, OSU Project Manager, City of Corvallis, and FS Landscape Manager or designee prior to any site work or grading is started.
During this meeting the pre-construction evaluation of those trees identified to remain shall be completed.
The contractor is responsible for maintaining all tree protection measures during all construction phases of the project.
The project arborist and OSU Project Manager and FS Landscape Manager or designee shall be contacted immediately if any of the trees on site are damaged during the construction of the project. The project arborist in consultation with the OSU Project Manager and FS Landscape Manager or designee will assess the damage to any tree and provide corrective measures, which may include pruning; tree wound repair, or even removal.
Upon completion of the project the project arborist will contact the OSU Project Manager and review the post construction evaluation of the trees on the site.
No tree shall be removed from the site without the completion of a tree condition report and prior notification and approval of the OSU Project Manager.
Tree removal within the OSU National Historic District requires a Historic Tree Checklist to ensure that any trees being removed are not considered historic. An arborist report must accompany the Historic Tree Checklist.
PART 2: MATERIALS
The contractor is responsible for installing a tree protection fence around all the trees identified to remain on site prior to the start of any site work, grading, or staging of any equipment or materials.
The tree protection fence shall be a galvanized chain link fence that measures a minimum of six feet high.
The fence shall be secured using steel posts that are the same height as the fence.
The steel posts shall be driven no less than two feet into the ground, and be a minimum of ten feet apart.
A highly visible sign shall be posted on the chain link fence demarking the area as a tree root protection zone. The sign shall remain posted and unobstructed until the project is completed.
PART 3: EXECUTION
Provide a copy of the completed site survey (see General Requirements 1.1.G) to the project consulting arborist and the Landscape Architect, prior to the development of the tree protection plan.
Pre-Construction Tree Assessment: Prior any site work, grading, staging of equipment, materials or any other mobilization of the project, the project arborist shall complete a pre-construction assessment report that outlines the physical conditions of the trees identified to remain on the site. The project arborist shall review the report with the OSU Project Manager and the FS Landscape Manager or designee.
The OSU FS Landscape Manager or designee shall provide written notification to the project arborist that the report has been reviewed and is acceptable prior to the mobilization of the project.
The assessment report shall provide any specific tree protection measures required to ensure the health and vigor of the trees during the construction of the project.
The assessment report shall also include a value appraisal of the trees completed according to the most recent edition of the Council of Tree and Landscape Appraiser standards.
The value of the trees that are to remain will be provided to the contractor prior to the mobilization of the site to ensure the contractor is aware of the replacement cost of the trees as outline in the appraisal report.
Tree Protection Areas: Prior any site work, grading, staging of equipment, materials or any other mobilization of the project the contractor shall establish the tree root protection zones as specified in the tree protection plan and install the specified fencing.
This protection area shall be maintained by the contractor during all phases of construction and only removed upon demobilization of the site.
In consultation with the OSU Project Manager and OSU FS Landscape Manager or designee, the project arborist shall recommend corrective measures for any tree damaged during construction,
Prior to any removal of a damaged tree the project arborist will ensure a replacement cost is determined for the damaged tree.
The Project Arborist shall complete a post construction assessment of the trees to determine the condition of the trees. The report shall be submitted to the OSU Project Manager and OSU FS Landscape Manager or designee for review and approval.
The OSU FS Landscape Manager or designee shall provide written notification that the post construction report has been reviewed and accepted prior to the close out of the project.
There shall be no alteration or disturbance of existing grade of any kind within the TRPZ.
No alteration of drainage flow into the TRPZ shall be permitted without the written authorization from the project arborist.
No storage of construction materials, equipment or supplies of any kind shall be permitted within the TRPZ.
No disposal of any liquids of any kind shall be permitted within the TRPZ.
No movement of vehicles, equipment, pedestrians, etc. shall be permitted within the TRPZ.
No excavation or trenching shall be permitted within the TRPZ.
No tunneling under the TRPZ without prior written authorization from the project arborist and landscape coordinator.
No roots extending beyond the TRPZ shall be pruned or cut without prior authorization from the project arborist.
No exceptions of the tree protection measures shall be provided without written approval from the OSU Project Manager and the OSU FS Landscape Manager or designee.
Comply with City of Corvallis requirements for tree protection.
All site and landscape plans shall identify the trees that are to remain, the trees to be removed, the tree root protection zone, and protection fencing.
Plans should be reviewed by the City of Corvallis.
TREE DAMAGE AND REPAIR
Upon notification of a damaged tree, the Project Arborist shall inspect the tree and assess the damage. The arborist shall outline in writing the corrective measures necessary to repair the damage.
If a tree is to be removed as a result of construction related damage then the cost of the removal and replacement and one year establishment care of the tree shall be the responsibility of the general contractor.
Up to 8” DBH: Same size as damaged tree, species selected by Landscape Architect after consulting with OSU Project Manager and OSU FS Landscape Manager or designee.
Over 8” DBH: Compensate OSU as determined by value appraisal completed by project arborist according to the most recent Council of Tree and Landscape Appraiser standards.
Replacement shrubs and groundcovers: Same size and quality as damaged shrub and groundcover, species selected by project Landscape Architect in consultation with the OSU Project Manager and OSU FS Landscape Manager.