06/27/2001 Env Bd Packet - Laserfiche WebLink

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TREE PRESERVATION POLICY materials within the critical root zones of trees. 3. Changes in soil chemistry will adversely affect tree survival. The moist frequent occurrence is the change (decrease) in soil acidity by concrete washout. Most trees native to Anoka County area prefer slightly acid soils; concrete residues are highly basic. The leakage or spillage of toxic materials such as fuels or paints can be fatal for trees. D. Trunk and crown disturbances are generally mechanical in nature and are either caused directly by clearing and grading machinery, or indirectly by debris being cleared and falling into trees marked for protection. 1. Common forms of damage include stripped bark and cambium, split trunks, and broken limbs. 2. Damage also occurs from the posting of signs such as building permits, or survey markers on trees. 3. Indirect damage can be caused by the placement of burn . holes or debris fires too close to trees. The possible range of damages include scorched trunks with some cambial dieback, the loss of foliage due to evaporative heat stress (leaf desiccation), and completely burned trunks and crowns. SECTION VI. METHODS OF TREE PROTECTION A. Planning and considerations. Tree space is the most critical factor in tree protection throughout the development process. The root system of trees can easily extend beyond the dripline of the tree canopy (Figure 3). The root system within the dripline region is generally considered to be the critical root zone. Disturbance within this zone can directly affect a tree's chances. With reference to root zones, the following standards shall apply: 1. The use of tree save islands and stands is encouraged rather than the protection of individual (non - specimen) trees scattered throughout a site. This will facilitate ease in overall site organization as related to tree protection. 2. The protective zone of specimen trees or stands of trees or otherwise designated tree save areas shall include no less than the total area beneath the tree(s) canopy as defined by the farthest canopy dripline of the tree(s). In some instances, the City Forester may require a protective zone in excess of the area defined by the tree's dripline. 3. Layout of the project site utility and grading plans should accommodate the required tree protective zones. Utilities must be placed along corridors between tree protective zones. 4. Construction site activities such as parking, material storage, concrete washout, hole placement, etc., shall be arranged so as to prevent disturbances within tree protective zones. 5. No disturbance shall occur within the protective zone of the specimen trees or stands of trees without prior approval by the City Forester. B. Protective Barriers Page 5