Agenda - Environmental Policy Board - 03/04/2013

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areas. Indicated elevations may be based on United States Geological Survey data. (d) Tree preservation barriers. (1) All tree protection areas are recommended to be designated as such with "Tree Save Area signs posted in addition to the required protective fencing. Signs requesting sub - contractor cooperation and compliance with tree protection standards are recommended for site entrances. (2) Before any construction or grading takes place, snow fencing or erosion control fencing shall be placed around the borders of woodlots at the dripline of large trees to be preserved. Signs shall be placed along this fence line prohibiting grading beyond the fence line. (3) These fences will be orange polyethylene laminar safety fencing or of woven polyethylene fabric (silt fencing). (4) Passive forms of tree protection may be utilized to delineate tree save areas outside of the MUSA line with approval of the city. These areas must be completely surrounded with continuous rope or flagging (heavy mil - minimum four inches wide). "Keep Out" or "Tree Save" signage must accompany all passive tree protection methods. (5) No construction shall begin until this work has been completed, inspected, and accepted by the city. (6) Silt barriers or similarly effective erosion control barriers shall be required in any area where erosion or siltation may cause damage to protected trees. (7) All protective tree fencing, staking or continuous ribbon and all erosion control barriers must be installed prior to and maintained throughout the land disturbance and construction process, and should not be removed until acceptable vegetation is established. (e) Critical root zone. The root system within the dripline is generally considered to be the critical root zone. To protect these critical root zones, a tree protection area shall be established around each tree or group of trees to be retained. (1) The tree protection area shall include no less than the total area beneath the tree canopy as defined by the dripline of the tree or group of trees collectively. (2) Wherein authorized excavations it becomes necessary to expose or cut roots more than one inch in diameter, it shall be the duty of the contractor to protect such root under advice from the city. (3) All open trenching is prohibited. Utility installation within the dripline of protected trees, during construction or thereafter, can only occur using trenchless methods. (4) The mowing, clearing, and grubbing of brush located within or under the dripline of protected trees may be allowed, provided such mowing, clearing, or grubbing is accomplished by hand or by mowers. The use of heavy equipment for this purpose shall not be allowed.