NOMENCLATURE height of tree above 5-ft mark, ft stem diameter at 5-ft above ground level, in. height above ground at which deflection measurements were made, ft stem diameter et deflection measurement point, in. height cf crown base above ground, ft stem diameter of crown base, in. height of break above ground, ft tree natural period, sec bare stem natural period, sec weight of dry crown, lb horizontal applied force at breakage, 1b are deflection at breakage, ft 46 SECRET - RESTRICTED DATA