TIMBER YIELDS. 



41 



upon which this table is based, were carefully made, and it is believed 

 the table is a fair estimate of what may be expected. It is exceed- 

 ingly probable that it underestimates rather than overestimates, since 

 not only were the most conservative figures used throughout, but no 

 allowance has been made for the improved conditions for forest growth 

 which will result under the application of conservative lumbering. 



The table also shows the yield per acre of merchantable pine which 

 may be expected after twenty, thirty, and forty years, cutting to the 

 diameter limits of 12, 11, 16, 18, and 20 inches breasthigh, and also 

 the time required before a yield equal to the present merchantable 

 stand may again be obtained. 



Table No. 12. 



-Present (i n>! future yields of pine per acre, and time necessary before the 

 present yield may again be obtained. 



It will be noticed that in general the cut after twenty years increases 

 as the diameter limit is raised; that at thirty years the cut increases 

 to the 16-inch limit, and then falls away again, and that at forty years 

 it decreases as the diameter limit increases. 



The time required before equal cuts can again be obtained is irregular 

 and needs explanation. Ordinarily, raising the diameter limit decreases 

 the time. But the table shows that the time is here the same whether 

 the diameter limit is 12 or 20 inches — forty-two years in each case. 

 This is due partly to the fact that the growth of the pine of small 

 diameters, especially that of the Loblolly, is very rapid. In forty- 

 two years Loblolly, with a present diameter of 12 inches, and Short- 

 leaf, with a present diameter of 14 inches, will have passed the L>o-inch 

 limit, and Loblolly of 2 inches mid Shortleaf of 5 inches will have 

 passed the 12-inch limit. A second reason for the disproportionate 

 length of the period required to produce a second crop equal to the 

 first at a 20-inch diameter limit is the tact that the forest is ix abnormal." 

 the number of trees between 14 and 20 inches being especially small. 

 as is shown by tig. 1, the probable result of the severer fires due to 

 the accumulated rubbish when tires first became frequent. These are 

 just the trees which would have to furnish the next equal crop cutting 

 to a diameter limit of 20 inches. 



