Some Observations on the Growth in 



Thickness of Trees, especially with Regard 



to that of Cryptomeria japonica, Don. 1 



By 

 Yudzuru Ogura 



The importance of the study of growth of plants is two-fold, 

 /. e. firstly, from the pure botanical standpoint, and secondly, from 

 the economic point of view, especially with regard to growth 

 in thickness of timber trees. So it has been studied by the authors 

 of forestry, naturally in the planted trees comparative^ of younger 

 age. My interest was, however, chiefly in the pure botanical point 

 of view, rather than the direct economical side ; and it seemed 

 much desirable to make a similar somewhat detailed study in 

 the much older and wild-grown trees in addition to the typical forest 

 trees. In this respect, the present investigation may serve a certain 

 addition to our knowledge of the type of growth in thickness of trees, 

 as well as of the dimensions of xylem-elements of wood. 



The main materials which I have investigated are the following : 



No. 



Names of Trees 



Habitat 



Numbers 

 of Annu- 

 al rings 



Average 

 radii 

 (cm.) 



i 



Crypiomwia japonica, Don. 



Kiyosumi (Awa) 



87 



19.6 



ii 



V 7) 7> 



» » 



102 



15.5 



in 



>> n >> 



}■> » 



91 



14.8 



IV 



>> >> >> 



Nikko (Shimotsuke) 



72 



23.1 



V 



>> j> t> 



» » 



94 



16.4 



VI 



» » » 



Tokyo 



49 



10.1 



VII 



>> >> »> 



Sakurajima (Satsuroa) 



90 



40.3 



1. This paper is an abstract from the Article in Japanese of the same title, published 

 in this magazine [p. (146)-(162), (167)-(180), (185)-(19i)]- The abbreviation "Art. 

 Jap." throughout the present paper refers to the latter. 



