Control of Tree Density for Making Single Storied Stand of Sanbu-sugi into Multiple Storied Stand

Abstract

After researching on single storied stand of Sanbu-sugi standing on flat ground in Hokuso region, Chiba prefecture, it was attempted to find a relating between a relative illuminance and factors of stand structure, that is, tree height, crown length, breast height diameter, stand density. The result was as follows: RI=-(G×Hk)/(0.210H-0.738)+100 whereRI=Relative illuminance (%) H=Mean tree height (m) Hk=Mean crown length(m) G=Basal area (m^2/ha) Next, this equation and the volume increment shown in the yield tables of Sanbu-sugi stands were used to evaluatee the decrease of relative illuminance. From these results, the stand density tables for making multiple storied stand of Sanbu-sugi was made out. And it can be used for the judgement of propriety on making single storied stand of Sanbu-sugi into multiple storied ones and the decision of stand density of multiple storied ones after setting up.