The Rate of Growth of Certain Species of Native 

 Trees of the State Reservation. 



BY STANLEY COULTER, PH.D., DEAN OF SCHOOL OP SCIENCE, DIRECTOR 

 OF LABORATORY, PURDUE UNIVERSITY. 



A fairly accurate knowledge of the rate of growth of the dif- 

 ferent species of trees used in the industries is evidently a matter 

 of extreme importance. "The very existence of a problem of 

 forest conservation is dependent upon the question of timber pro- 

 duction. If production falls below consumption at present or 

 threatens to in the future the problem is very real. If the produc- 

 tion exceeds consumption there is obAdously no problem of con- 

 servation to solve. "^ 



It is also clear that upon a knowledge of the growth-rate of 

 trees must depend the correct answer to the oft-repeated question 

 concerning the time necessary to bring certain species to market- 

 able size. The whole question of the economic possibilities in the 

 reforestation of denuded areas, of the returns to be expected in the 

 shorter rotations for the production of post and tie stuff depends 

 upon our knowledge of the growth rate of the forms with which we 

 are dealing. 



So many factors enter in the determination of the rate of tree 

 growth that studies of this nature must be regional. The results 

 are necessarily of fairly limited application. Some of the factors 

 determining tree growth are composition and strength of soil, its 

 porosity, the soil moisture, the exposure to light, the topography 

 and the climate. It is evident that conclusions drawn from a 

 study of tree growth in New York or Arkansas might not, in- 

 deed almost certainly would not, be correct for Indiana. 



Before further intelligent progress could be hoped for in for- 

 estal enterprises in the State it was necessary that accurate data 

 bearing upon this question should be collected. Studies in the rate 

 of growth of various tree species had previously been made by 

 Ziegler^ and the approximate rate of growth given for the north- 



* Ziegler, E. A. Rate of Forest Growth. Report of The National Conservation Commissic 

 Vol. 2, p. 203, 1. 909. 



' Ziegler, E. A., loc. cit. 



