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and on smoothing the curves for the mean trends of the factors, re- 

 presenting the growth of stands. 



As to grouping and grading, there are two methods in use, the 

 first being the horn method, after Baur ; and the second, the stem analysis 

 method. I do not propose to give here any account of the methods, for 

 we have no data for criticism. But for the sake of convenience and 

 simplicity, I used a method something like the horn method, i. e. a method 

 depending upon the laws governing the mutual relations on the factors, 

 V, H, G, N and D of sample plots, to one another and on their elements, 

 viz., the dimensions, v, h, d of test tree in each sample plot. This last 

 method has been described by such authorities as Schuberg, Wimmenauer, 

 Eichhorn and Gehrhardt. However it seems to me that in some points 

 the method can be improved ; also the laws, generalised while the laws can 

 be adopted to the grouping and grading as members of the same chain of 

 growth. Furthermore from the laws, I have readily deducted empirical 

 equations on the mutual relations on the factors representing the growth of 

 stand and on the elements representing the developments of individual tree 

 with respect to age and I have attempted a method of smoothing curves 

 for the mean trends of the factors. One illustration of the applications 

 of the method, I have reported in Japanese Bulletin No. 11, in 1915, 

 under the title " The growth and yield for Cryptomeria Stands." 



The yield tables, constructed by many authorities, excepting 

 Schuberg and Schiffel, are limited to one of the forms of density. 

 In practice it is evident that the overheaded leaf canopy of pure, 

 even-aged, normally stocked stands will be of different forms of density. 

 This has received considerable attention and is of theoretical interest at 

 least, as well as perhaps of much practical importance in ascertaining the 

 degree of influence on the growth and yield of stand by the sort and 

 grade of thinnings. Recently Dr. Schwappach, in his work " Die Kiefer," 

 published a yield table from the data obtained from the permanent sample 

 plots for the discussion on the grades of thinnings, but unfortunately he 

 has not published analytical investigations of the laws subsisting between 

 the growth and yield of stand and the development of its elements with 

 regard to the form of density. While I have distinguished the growth and 

 yield of Cryptomeria for each quality of site under different forms of 

 density and have attempted to solve the question relating to the forms of 



