FIRST STUDY ON THE CHARACTERISTICS OF SELF=REGENERATING STANDS IN NIPPON

As we have seen in the case of Abies stand, the stand forms will, also, be classified into the four types, that is, Iα, Iβ, and IIγ, IIδ.So far as I have observed in Cryptomeria stands, there are great many stands corresponding to the stand-type IIγ in different stages in Akita province, while for the stand type Iβ, there are only the rudiment stages and for the stands of the stand-type Iα and IIγ, are now going to loss of sight. Because the stand corresponding to the stand-type Iα, gives the bigger logs and the better quality of timber than the stand corresponding to any other stand-type, while the stand corresponding to the stand-type IIγ, gives very poor appearance for the stand formation, something like a devastated one with reference to the stand corresponding to the stand-type Iα. In consequence of adjustment of the orders of stands in the working circle, the stand corresponding to the stand-type Iα, assumed as an over-mature one and the stand corresponding to the stand-type IIδ, assumed as a devastated one, are intended to be clearly cutted according to the principle of clear cutting system and of plantation. The stand corresponding to the stand-type Iβ, though it was only the rudimental form, are now showing its appearance on the clear cutted area that has been carried on about 20-50 years ago.On the cyclical changes of the stand formation for Cryptomeria stand, one can readily suggested from the history of forest management of Akita province in the federal ages. On this points, I would like to described in the other part, the forest management.The explanations on the distributions of the diameters, heights and ages given in the previous section lead me to summarized as follows:Lastly percetage, the number of trees in each stand type is as follows: