Abstract
Stand structure investigations of old-aged sugi stands were carried out at Aizu in Fukushima Prefecture. Current data between 80 and 100 years and previous data were examined in accordance with the average upper story stand height. Then they were analyzed and a minimum numerical value was assigned using the method of least squares to make a site index guide curve. As a result, height growth could be approximately confirmed using the Mitscherlich function. With this result, we could predict that an upward tendency is occurring compared with the usual height growth of the same age grade after 60 years. As years of the stand passed by, the differences between both guide curves also increased.
