Half-century Check Method Experiment in Oketo Experimental Forest

- Result and Application -

Abstract

The Oketo Experimental Forest (est. 1955) is situated within a prefectural forest in Oketo Town in eastern Hokkaido. In this forest, trees have been felled at eight-year intervals (management stages) and five management stages have been completed thus far. For all forest units, the diameter-tree curve (tree diameter vs. number of trees per hectare), on the semi-logarithmic graph with the diameter grade on the horizontal axis and the number of trees per hectare on the vertical axis (logarithmic values), was essentially a straight line (correlation coefficient≒1), confirming that the accurate estimation of stand volume from diameter-tree regression lines is possible. Since one regression line indicates the stand volume of one forest unit, the area between two lines represents the difference in volume between the two forest units (amount of trees felled). Based on this relationship, a simulation method that optimizes natural forest managements was developed.