Laserfiche WebLink
APPENDIX B <br />TREE AND SITE REt-ATED DISTURBANCES <br /> <br />A. Direct physical root damage most frequently occurs during site clearing and grading <br />operations, ,g, here transport (feeder) roots are cut, tom, or removed. <br /> <br /> 1. Transport and feeder roots tend to tangle and fuse among the roots of <br />adjacent tre~s. The removal of trees with heavy machinery along the outer periphery of a <br />tree save ar~ causes root damage. <br /> 2. The most substantial form of root damage for all root types occurs in the <br />form of cut roots. Roots are cut in grade reduction, excavation, and trenching for <br />underground utilities, sanitary sewer, or storm sewer Iines. <br /> 3. A more subtle type of root damage is the loss of feeder roots. Since feeder <br />roots norm~ly occur within the organic layer and the surface four (4") inches of top soil, <br />these roots Can be easily damaged by the compaction from a single bulldozer pass. The <br />stripping of.top soil within a tree's critical root zone can totally eliminate its feeder root <br />system. <br /> <br />B. Indirect root damage through site modification can result from positive grade <br />changes, tem~ porary storage of fill material, the sedimentation of erosion materials, soil <br />compaction,/and soil chemical changes. <br /> <br /> 1. · Positive grade changes from fill and sedimentation causes a decrease in soil <br />oxygen levels. An increase in soil carbon dioxide and other toxic gasses can also occur, <br />leading to l~ge areas of anaerobic conditions. Anaerobic soil conditions cause a decrease <br />in the root respiration process which is essential for the uptake and transport of minerals <br />and nutrients. <br /> 2. Anaerobic soil conditions are also produced by soil compaction, the increase <br />in soil bulk density with a decrease in' soil pore space. Compacted soil is also impervious <br />to root penetration, and thus inhibits root development. Soil compaction is generally <br />caused by the weight and vibrations of heavy machine~, vehicle parking, and the storage <br />of fill and/or:construction materials within the root zones of trees. <br /> 3. Changes in soil chemistry will adversely affect tree survival. The most <br />frequent occurrence is the change (decrease) in soil acidity by concrete washout. Most <br />trees native to Anoka County area prefer slightly acidic pH soils; concrete residues have <br />highly basic pH values. The leakage, spillage, or rinsing of toxic materials such as fuels or <br />paints can be' fatal for trees. <br /> <br />Co <br />caused <br />falling <br /> <br />Trunk and crown disturbances are generally mechanical in nature and are either <br />directly by clearing and grading machinery, or indirectly by debris being cleared and <br />into trees marked for protection. <br /> <br /> 1. Common forms of damage include stripped bark, split trunks, and broken <br />limbs. <br /> 2. Damage also occurs from the posti.ng of signs such as building permits, or <br />survey markers on trees. <br /> 3. : Indirect damage can be caused by the placement of bum holes or debris fires <br />too close to trees. The possible range of damages include scorched trunks with cambial <br />dieback, the loss of foliage due to evaporative heat stress (leaf desiccation), and completely <br />burned trunk~; and crowns. <br /> <br />l0 <br /> <br /> <br />