IX. A, 6 



Brown and Mathews: Dipterocarp Forests 



515 



compared, it will be seen that the trees on type area A and the 

 trail trees have approximately equal rates of growth, which 

 are faster than those of the trees on type areas B and C. Tree 

 class III thus shows, as do the other classes, faster rates of 

 growth in cut-over than in virgin forest. It is noticeable that 

 the curves for tree classes II and III on the different areas 



Age in years. 



eo H) 60 so 100 120 140 160 ISO ZOO iZO B40 Z60 ZSO 3,''0 



70 



SO 



B so 



a 



40 



u 



i 



5 30 



to 



10 















/ 































1 



/ 































/ 



/ 































v 





















f\ 











> 



r 





















9 



1 











Jl 





















/ 











/7 



x^- 



/ 











^. 



^.-^ 



^^^ 













4'h 



i 6y 



i 



' 





^' 



^^' 



















/ 







r 





P 



^ 

























p'j 





/ 





















/ 



/ 



<> 



^ 

























Yp 



/ 



J 



w 

























i 





^' 





























<"-' 































































































Fig. 10. Rates of growth of trees of class II. Bataan Province, Luzon. 



show approximately the same relative positions as do those for 

 the dipterocarps. 



In fig. 11 are presented curves showing the age of individuals 

 of different diameters of Shorea robusta growing in virgin 

 stands. The data from which these curves were drawn were 

 collected in India.^* 



"Caccia, A, M. P., A preliminary note on the development of the sal 

 in volume and money value, Indian Forest Rec. (1908), 1, 85. 



