36 BULLETIN 308, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 18.—Relation between tree density and yield of shorileaf pine in board 
feet per acre. 
i i 
| s Trees 8| Sawtimber.? | Aver- Trees 8 | Saw timber.2 | 4 ver- 
inches age inches age 
Totaltreesper | and [ dia- Total trees per | and dia- 
acre. over | Scrib- wane meter acre. over | Scrib- mania meter 
in dia-} ner | >}. | (breast- in dia-| ner ts fi (breast- 
meter. | rule. * | high). meter. | rule. * | high) 
| ANd 20) 9A eo ER 
Num- | Board | Board Yum- | Board | Board 
Number. ber. fee. feet. | Inches. Number. ber. feet. feet. | Inches. 
ANS REA 130 | 11,250 | 6,600 1. 5 OTS 0 255 | 15,350 | 7,900 8.1 
No, el ie ee 175 | 13,500 | 8,450 10-0 NL 55oe eee en ae 235 | 13,200 | 6,800 77 
| 7 a ee 215 116,000 | 9,700| 10.4 || 600.......-.---- 215 | 11,250 | 5,800 7.3 
Be Seee oe Aaa 260 | 18,100 | 10,600 O58) 1) 6502-25532 5 195 | 9,250 | 4,450 7.0 
| SHU ESE STEEN 290 | 19,400 | 10, 800 0. 451 400). Sek See 180 | 7,500] 3,200 6.6 
AGI Se 2 290 | 19,100 | i0, 200 SOyll 750! Lcee eee 160 | 5,900 | 2,000 6.3 
AOS 224. 260 | 17,500 | 9,000 8.5 || S00bS 2421) sei te 140 | 4,250 800 6.0 
| 
fi 1A oe old stand of varying densities on good quality site and protected against fire, Montgomery 
‘ounty, Ark. 
2 Yield of trees 8 inches and over in diameter at breast-height. 
In a selected old-field stand in Arkansas, 20 years old (Pl. VII, 
fig. 1) a density of 1,440 trees per acre gave a yield of 1,600 board 
feet, counting all trees 8 inches and over in diameter, while a normal 
stocking of 520 trees per acre in the same stand yielded 10,200 feet 
of saw timber. The overstocked stand contained only 40 trees per 
acre 8 inches and over in diameter and merchantable for saw timber, 
the well-stocked stands 200. The relation between number of trees 
per acre and diameter growth is so regular that it is almost sus- 
ceptible of expression with mathematical exactness. The sections in 
Plate VIII represent the average growth in a 33-year-old stand of 
shortleaf pine coming up under full-lght exposure in an opening of 
about 10 square miles caused by a cyclone. A density of 370 trees 
per acre gave a yield of 18,000 feet of saw timber, a density of 550 
trees per acre 21,800 feet. The trees widely spaced averaged 1 inch 
larger in breast-high diameter, thus yielding a higher grade of 
lumber. 
The number of trees to be left per acre in thinning shortleaf stands 
of specified ages varies chiefly with the quality of the situation. 
Table 19 indicates approximately the number of trees in natural un- 
thinned stands and also the trees left after thinning. The better class 
is representative of the more southern and western portions of the 
shortleaf range; the poorer class, of unfavorable local situations in 
this portion of the range, and the more northern and eastern areas 
of distribution. 
