Abstract
Knowing root system is basic but important information for care and transplantation of planted trees. However, only very limited methods such as excavation or washing out roots by high-pressured water have been used for root system investigation. The authors tried to develop a quite new non-destructive method to investigate tree root system, especially horizontal distribution of them, by using vibration. Impacts were given to Robinia pseudo-acacia's trunks by hammer and speed of vibration were measured and analyzed. Consequently, it became possible to estimate direction of main roots in a radius of 2.5m of target trees. Moreover, drawing estimated horizontal root existing area became possible by using Sufer8 and the performance of the estimation was between 59.8-73.6% including adjacent neighboring tree's roots and 51.7-70.0% excluding them.
