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IRRIGATION FINDINGS <br /> The revised findings for irrigation are based on the following: <br /> 1. Research paper prepared by Peter Torres, Oregon State University, March 1997: <br /> "Nonspecific root decline in Douglas-fir due to urban soils syndrome." <br /> 2. Conversations with Dr. Everett Hansen, Department of Botany and Pathology, Oregon State <br /> University; Doug Dollarhide, Parks Manager, Corvallis Parks Department regarding <br /> extensive Douglas -fir windthrow and irrigation issues in Avery Park. <br /> 3. Experience and knowledge of Scott Ferguson, professional forester, ITS and Nathaniel <br /> Sperry, arborist, Sperry Tree Care Company. <br /> 4. Observations of Ferguson and Sperry over the summer irrigation months and from post <br /> mortem analysis after the February 7 and March 2, 1999 storms in Hendricks Park. <br /> 5. Discussions with staff regarding irrigation regimens, schedules, and adaptive changes over <br /> recent years. <br /> re ared by Scott Ferguson, 6. Progress Reports No. 1 and 2, p p y g , March 12, 1999 and April 12, <br /> 1999: "An Assessment of stand conditions in Hendricks Park following recent windthrow <br /> events," Part 1: Underlying processes and risk factors; Part II: Summary of findings from <br /> on -site windthrow examination and discussion of management strategy and options. <br /> Context Findings <br /> Two context findings are important as background information for the irrigation findings: <br /> 1. Tree stress and decline in the developed, high use areas of Hendricks Park are <br /> believed to be caused by a multiplicity of factors. These include: <br /> a) soil compaction from several decades of recreational use <br /> b) construction impact from roadways, parking lots, recreation facilities (i.e. rock <br /> restroom), trails, irrigation system, and a number of utilities which cross the park <br /> c) past removal of hazardous trees, including stand impacts and soil compaction <br /> d) impact from maintenance vehicles, including utilities and park maintenance <br /> e) interference with natural drainage patterns caused by human disturbances listed above <br /> f) poorly drained soils, naturally wet conditions in some areas, and saturated soils from <br /> irrigation <br /> g) with loss of trees, less water is drawn from the soil, creating less transpiration and <br /> therefore more saturated conditions <br />