18 



BULLETIN 1061, U. S. DEPARTMENT OF AGPJCULTUEE. 



be sawed out by using the tree above a 1-foot stump and down to 

 a top diameter of 4.6 inches. It is the form of utilization now gen- 

 eral in parts of New England. Another column shows the amount 

 of* lumber yielded per acre according to the Doyle log rule — which 

 is in common use in the South — and the difference is striking. Tab- 

 ulated information of this kind will be found useful in predicting 

 the amount of growth that may be expected to take place during a 

 specified period — 5 years or multiples thereof — upon different qual- 

 ities of situation or classes of land. On medium land, for ex- 

 ample, well-stocked longleaf stands at 40 years of age have been 

 found containing an average of 6,200 board feet, and these may be 

 expected to grow 4,200 board feet during the next 10 years, at which 

 time they will contain a total of about 10.400 feet. On good land, 

 or favorable situations, measured 40-year-old stands, well stocked 

 with trees, have contained an average of about 11,000 board feet, 

 increasing during the next 10 years by about 5,200 board feet, to a 

 total of 16,200 feet at 50 years of age. The caution is here repeated 

 that these are fully stocked stands and very much better than the 

 average (PI. VII). The degree of stocking, or the amount of un- 

 used space in the stand, should be taken fully into account in esti- 

 mating any piece of timber. 



TABLE 9. 



Amount of saw timber in board feet grown in longleaf pine stands 

 that are even aged and well stocked with trees. 



Age 

 of 



stand. 



Years. 

 30 

 35 

 40 

 45 

 50 

 55 

 60 

 65 

 70 



Mill scale, or actual cut. 



Trees 10 inches and over in 

 diameter. 



Better Medium 

 land, i land. 



Poorer 

 land. 



900 

 500 

 000 

 600 

 200 

 800 

 400 

 700 



1,200 

 3, 800 

 6,200 

 8,400 

 10, 400 

 12, 400 

 14, 400 



16, 200 



17, 900 



1,500 

 3,100 

 4,600 

 6,100 

 7,500 

 8,800 

 10,000 



Trees 8 inches and over in 

 diameter. 



Better Medium 

 land. land. 



10, 800 

 14, 200 

 17, 100 

 19, 600 

 21, 800 

 23, 700 



25, 300 



26, 900 

 28,900 



5,700 

 8,200 

 10, 400 

 12, 600 

 14, 400 



16, 000 



17, 400 



18, 800 

 20, 200 



Poorer 

 land. 



700 

 2,200 

 3,800 

 5,300 

 6,900 

 8, 200 

 9,500 

 10, 700 

 11,900 



Doyle rule. 



Trees 7 inches and over in 

 diameter. 



Better 



Medium 



land. 



land. 



3,500 



1,900 



4,800 



2,900 



6,200 



4,000 



7,600 



5,000 



9,000 



6,100 



10, 300 



7,200 



11, 600 



8,200 



12,900 



9,200 



14, 200 



10, 200 



Poorer 

 land. 



300 

 1,000 

 1,700 

 2, 500 

 3,200 

 4,000 

 4,700 

 5, 500 

 6, 200 



The final yields here shown, it should be noted, are the full con- 

 tents of the stand at the assigned ages and do not include timber 

 that may have been produced previously, or the intermediate yield, 

 often a very considerable amount. This is the product of any thin- 

 nings that may have been made (see under "Cutting") and of the 

 timber that has died out during the life of the stand. With advance 

 in the age and size of the trees there comes a natural reduction in 

 the number of trees by the weaker giving way. The process may 



