STATISTICS AND CONCLUSIONS. 



23 



behind for the next twenty-five to thirty years, then proceeds at about the same rate, but persisting 

 longer than the Ijoblolly. At the age of fifty years the Cuban Pine with 4G cubic feet has made 

 nearly twice the amount of the Loblolly and more than four times that of the Longleaf, but at one 

 hundred years the difterence is reduced, being then 115, 90, and 55 cubic feet, respectively, for the 

 three species. 



Both Loblolly and Shortleaf Tine reach their maximum growth sooner than the other two 

 species. While these still show a x>ersistently ascending line at one hundred and twenty to one 

 hundred and forty years, tlie rate of growth in the Loblolly shows a decline after the one hundredth 

 year, and the Shortleaf has done its best by the eiglitieth year. These facts give indications as to 

 the rotation under which these various species may be managed. 



Fig. 6. — Diagram showing comparative progress of diameter growth in average trees. 



As stated before, the growth of trees, especially in the virgin forest, is quite variable even for 

 the same species and same soil conditions; an average, therefore, like the one presented in the 

 diagrams, liowever perfect, could apply only when large numbers are considered. Thus there are 

 fast-growing trees of Longleaf and slow-growing of Cuban or Loblolly Pine. Yet the diagrams 

 will fairly well represent the average growth, with the possible exception of the Cuban Pine, for 

 which the number of measurements was too small to furnish reliable data. 



STATISTICS AND CONCLUSIONS. 



The greatest difficulty Dr. Mohr has found is in the statistical portions of his work. To deter- 

 mine the amounts of remaining timber supplies of the various species is almost an impossibility 

 without a very elaborate and laborious canvass, which, to be sure, it would appear our duty to 



