f Geophysical techniques applied to trees assessment

The problem of trees assessment is increasingly felt either as a life quality problem either as a safety problem within the city management. Many towns in Italy and in Europe have large boulevards and squares with trees, and parks surrounding historical buildings where citizens spend a noticeably part of their free time. These kind of “green belts” and areas are considered an essential part of the quality of life in the cities. At the same time, as these areas can be very crowd, the safety of people as far as the stability of the trees is concerned is a matter of primary importance. In the town of Turin (Italy) the Municipality has committed a research project to the university concerning methods of preventive diagnosis of tree pathologies that could compromise the overall stability of the tree itself. One of the main cause of the collapse of a tree is the decay of the bearing capacity of some of the primary roots (the largest ones). This decay is usually caused by some kind of fytopathology that deteriorate the wood of the root so that it misses both its function of bearing and feeding the tree. This deterioration either changes the physical characteristics of the wood either changes the water content in the peripheral part of the tree immediately above the ground where the root lies. According to these phenomena a detailed survey has been carried out following these two ways: to check if there is a geophysical technique able to find decayed roots in the ground; to check if there is a geophysical technique able to see the change in water content in the peripheral part of the wood immediately above the ground of a decayed root.