developing a practical mathematic model, to estimate strength and factor of safety of embowed crown trees, against wind force

conditional monitoring is prerequisite to prevent severe damage or falling down the trees. problems such as trunk decays, reduces trees resistance against wind and floods. in this study, a mathematical modeling technique is being selected to determine the trees strength against such events. finally, an applicable model for safety factor was created by having numeral (dimensions of crown and trunk, crown density, crown volume, section diameter, internal cavity diameter etc.) and mechanical (modulus of elasticity of wood, allowable stress, maximum wind speed, crown and trunk weight) parameters of tree. by using this model we may estimate the total maximum stress in critical plane of the trunk. comparing allowable stress of trunk wood leads us to calculate the safety factor of the tree. the results indicated that the total maximum stress in trunk increases exponentially after the diameter of internal cavity exceeds 40 percent of trunk in critical plane.