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V. Tree & Site Related Disturbances. <br />A. Tree protection zones, specimen trees or stands of trees designated to* be <br />saved must be protected from the following damages which may occur during all <br />phases of land disturbance and construction processes. Methods of tree protection <br />and disturbance prevention are provided in Section VI. <br />1 . Direct physical root damage <br />2. Indirect root damage <br />3. Trunk and crown disturbance <br />B. Direct physical root damage most frequently occurs during site clearing and <br />grading operations, where transport or feeder roots are cut, tom, or removed. <br />1. Transport and feeder roots tend to tangle and fuse among the roots of <br />adjacent trees. The removal of trees -vith heavy machinery along the <br />outer periphery' of a tree save area causes root damage. <br />2. The most substantial form of root damage for all root types occurs in <br />the form of cut roots. Roots are cut in grade reduction, or from <br />trenching for underground utilities, sanitary sewer, or storm sewer <br />lines. <br />3. A more subtle type of root damage is the loss of feeder roots. Feeder <br />roots normally occur within the organic layer, and the surface four <br />inches (4") of top soil, subsequently, these roots can be easily <br />damaged by the track action from a single bulldozer pass. The <br />stripping of top soil within a tree's critical root zone can totally <br />eliminate its feeder root system. <br />C. Indirect root damage through site modification can result from positive grade <br />changes, temporary' storage of fill material, the sedimentation of erosion <br />materials, soil compaction, and soil chemical changes. <br />1 . Positive grade changes from fill and sedimentation causes a decrease <br />in soil oxygen levels. An increase in soil carbon dioxide and other <br />toxic gases can also occur, leading to large areas of anaerobic <br />conditions. Anaerobic soil conditions cause a decrease in the root <br />respiration process which is essential for the uptake and transport of <br />minerals and nutrients. <br />2. Anaerobic soil conditions are also produced by soil compaction, the <br />increase in soil bulk density with a decrease in soil spore space. <br />Compacted soil is also impervious to root penetration, and thus <br />inhibits root development. Soil compaction is generally caused by the