APPLICATION OF THE YIELD TABLES. 49 
EXAMPLE NO.1. 
A man owns 30,000 acres, which yields on an average 3,000 board feet per acre of 
Spruce 10 inches and over in diameter. To what limit will it be most profitable in. 
the long run for him to cut, how much can be cut annually if he wishes to obtain a 
sustained annual yield, and how soon can he return to the portion lumbered over 
the first year and cut the same amount of timber above the same diameter limit as 
at first? 
If the diameter limit is 10 inches, the total stand is 30,000 by 3,000=90,000,000 
board feet; the same yield can be obtained in 36 years (Table A, column 9); the 
area lumbered annually will be 30,000—36=833 acres; the annual cut will be 
90,000,000 — 362,500,000 board feet. 
If the diameter limit is 12 inches, the average stand per acre is 83 per cent of the 
stand of trees 10 inches and over (Table B, column 2), i. e., 2,490, or in round num- 
bers, 2,500 board feet. The total stand is 2,500 by 30,000—=75,000,000 board feet; 
the same yield can be obtained in 24 years (‘Table B, column 10); the area lumbered 
annually will be 30,000 — 24—1,250 acres; the annual cut will be 75,000,000 — 24 — 
3,125,000 board feet. . 
If the diameter limit is 14 inches, the average stand per acre is 61 per cent of the 
yield of trees 10 inches and over (Table C, column 2), i.e., 1,830, or in round num- 
bers 1,800 board feet. The total stand is 30,000 by 1,800—54,000,000 board feet; the 
same yield can be obtained in 19 years (Table C, column 8); the area sient erat over 
will be 30,000 — 191,579 acres; the annual cut will be 54,000,000 — 19 = 2,842,105 
board feet. 
By comparing these results it appears that, if it is desired to cut an equal amount 
of timber annually for an indefinite period, the largest yield can be obtained by 
cutting to a 12-inch limit. The area lumbered annually is about 400 acres greater 
than if 10 inches were the limit, but the annual cut is 625,000 board feet larger. 
Lumbering under these conditions would nevertheless be profitable, inasmuch as 
the average stand per acre for trees 12 inches and over in diameter is about 2,500 
board feet. 
EXAMPLE NO. 2. 
A man owns 1,000 acres, yielding 1,500 board feet of Spruce per acre, 12 inches 
and over in diameter. To what limit will it be most profitable in the long run to 
cut if he lumbers the entire tract in one year and how soon can he return fora 
second cut equal to the first? 
See Table B, column 3, for the amount nearest 1,500 board feet. The closest 
figure is 1,480 feet in the second line. All the desired information will be obtained 
on this line in the three tables. 
If the diameter limit is 10 inches, the average yield is, in round numbers, 2,000 
board feet (Table A, columii 1). The total stand is 1,000 by 2,000 2,000,000 board 
feet. The same yield can be obtained in 32 years (Table A, column 9). 
If the diameter limit is 12 inches, the average stand per acre is 1,500 board feet. 
(See above.) The total stand is 1,000 by 1,500—1,500,000 board feet. The same 
cut can be obtained in 21 years (Table B, column 10). 
If the diameter limit is 14 inches, the average stand per acre is 1,140, or in round 
numbers, 1,150 board feet (Table C, column 3). The total stand is 1,000 by 1,150— 
1,150,000 board feet. The same cut can be obtained in 16 years (Table C, column 8). 
If 10 inches is the limit, the tract will yield at present 2,000,000, and in 32 years 
the same amount again, or together, at that time, 4,000,000 feet. If 12 inches is the 
limit, 1,500,000 board feet can be obtained now, and in 32 years there can be cut 
2,664 feet per acre (Table B, column 9) plus 2 years’ growth. The latter is equiva- 
lent to 2,664 (column 9) minus 1,376 (column 7), divided by 5, or 248. The yield in 
32 years is then 2,664 + 248 — 2, 912 board feet per acre, or on ane whole tract, includ- 
ing the first cut, 4,412,000 board feet. If 14 inches is the limit, 1,150,000 board feet 
4364_No. 26 4 
