One characteristic of the system yield table is that it adapts flexibly to various stand structures and forest treatments. The purpose of this paper is to examine the practical use of system yield table making good use of this characteristic. In this paper, the volume of yield, utilization and net log income were predicted by a simulation model using a system yield table which incorporated data regarding various cutting age and thinning patterns in 275 artificial stands in the University Forest at Chichibu. The results of this prediction were as follows. 1) The rotation in maximum final mean annual increment of yield volume is about 60 years. 2) The rotation in maximum final mean annual increment of utilizing volume is a little longer than yield volume. 3) The rotation in maximum final mean annual increment of net log income of Hinoki cypress and Japanese larch is longer than yield volume by 15 years. 4) High site quality and high stand density have a tendency to shorten the rotation. This tendency is more pronounced in net log income, with site quality demonstrating a great deal of influence. 5) Depending on stand situation, the system yield table is able to make more precise decisions regarding cutting age. This is because of optimum rotations may be calculated for each stand.

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In this article the method for evaluating the potential timber productivity of forest stands is discussed. This research also addresses administrative demand that the evaluation method should be revised in accordance with the 1987 changes in the Basic Plan of Forest Resources. Both individual stands and regional forests were taken to be evaluation units. As for individual stands, the level of potential productivity was evaluated using quantity, quality and accessibility as factors. In the case of regional forests, sustainability was added to the above three factors. This method was applied to some private forest areas with good result.

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