ESTIMATES AND DISCUSSION. 



79 



TABLE 17. Cottonwood estimates lumber and fuel. 



1 Ten cubic feet of ma~>le cordwood mixed with cottonwood. 



2 Four rows ash on east, which are partially suppressed; value added to that of cottonwood. 

 s Not estimated. 



4 Some fuel removed in past. 



5 Carolina poplar. 



6 Soil moist, but rather light, sandy. 



7 Contains considerable saw stuff which was not estimated. 



8 Burned out at age of 5-6 years hence has value of coppice. 



9 Some fuel remove'! from time to time. 



t Three thousand feet of lumber per acre removed two years prior to estimate value calculated to date.. 



The points in Table 17 which bear upon the method of planting 

 for windbreak purposes are 



(1) The value per mile of the north-south row is strikingly greater 

 than that of the east-west row of the same age. 



(2) With these figures reduced to acre values, the discrepancy 

 practically disappears, except in the youngest windbreaks. In the 

 latter it seems that the north-south row gains in diameter and in 

 value more rapidly than the east-west row. 



(3) The percentage of volume merchantable for lumber is about 

 the same at all ages in the north-south row and in the grove, but at 

 the same ages is much lower in the east-west row. 



(4) The high annual value of groves is maintained by their rapid 

 increase in quality after the trees attain log size and there is every 

 indication that the maximum would not be reached for several years 

 after the age of 40. The relative value of rows and groves in this 

 respect is not clearly shown by any of these figures because from the 

 start the grove has been charged with the same area, which is not 

 increasing in size, while the row was at first charged with only a 

 narrow strip. Hence a sustained mean annual value per acre indi- 

 cates a much greater current value in the old grove than in the row. 



(5) The revenue has been slightly increased, and the efficiency of 

 the windbreak very greatly increased by underplanting the grove 

 with ash about six years after the first planting (No. 20). 



