Abstract
A tornado occurred on May 6, 2012 from Jyoso city to Tsukuba city in Ibaraki Prefecture. The tornado severely destroyed forests in some areas. We analyzed 5 damaged forests of the Yamaki and Hirasawa districts in Tsukuba city to clarify the characteristics of the damage due to the tornado. A circular damaged area with about 300 m of diameter was observed at the end of the path of the tornado. Except for the area, we recognized some characteristics of damage; (1) The severely destroyed areas occurred in a belt of about 100 m of width. (2) Almost all trees were damaged in the path of the tornado even though they were broad leaf trees or had low height-to-diameter ratio, the types of trees that would be expected to have strength in strong wind. (3) The damaged trees were usually fallen to the direction of the center of the tornado path showing the convergent wind caused by the tornado.
