Table 28. — Average net board-foot increment per acre, by forest type and 

 forest condition, 1938 



Table 29. — Increment, mortality, and net increment of saw timber 

 by species group and forest condition, 1938 



Forest type 



Old growth 



Loblolly pine 



Shortleaf pine 



Pond pine 



Longleaf pine 



Virginia pine 



White pine 



Cove hardwoods 



Bottom-land hardwoods 

 Upland hardwoods 



Average all types . 



Bd.ft. 

 204 

 206 

 42 

 73 

 173 

 44 

 147 

 230 



Bd.ft. 

 212 

 131 



75 

 94 



125 



-79 



78 



158 



Second 



growth 



sawlog 



size 



Bd. ft. 

 344 

 263 

 148 

 156 

 218 

 198 

 206 

 214 

 114 



247 



Bd.ft 

 213 

 179 

 124 

 133 

 179 

 162 

 125 

 170 

 100 



Under 



sawlog 



size 1 



£5 



Bd.ft. 



70 



Bd.ft 

 8 

 1 

 4 

 12 

 1 



Bd.ft. 

 206 

 158 

 58 

 62 

 118 

 117 

 101 

 141 

 67 



131 



1 Areas so classified contain scattered trees of sawlog or near-sawlog size. 



The average net increment per acre for all forest types 

 combined was not large in any of the forest conditions. 

 Uncut stands of second growth averaged 247 board feet, 

 but this could be increased to at least 350 feet with proper 

 management. In all the State, 53 percent of the forest 

 land was producing an average of 201 board feet per acre 

 per year, 39 percent was producing 58 board feet, and 8 

 percent was producing only 5 feet, or an over-all average of 

 131 board feet. This is distinctly unsatisfactory in view of 

 the latent productivity of the forest land and the increasing 

 demand for timber products. 



Net Board-Foot Increment 



In the record of saw-timber increment, mortality, and 

 net increment for 1938 as presented in table 29, mortality 

 in softwoods is 10 percent of increment, in hardwoods 12 

 percent, and in all species 11 percent. Nearly two-fifths 

 of the resultant net increment of softwoods and one-half 

 of that of hardwoods were attributable to the growth of 

 under-sawlog-size trees into sawlog sizes. 



Softwoods made up about 70 percent of the total net 

 increment. In this contribution old-growth softwood tim- 

 ber had little part, both because of the small volume of 

 growing stock and because of the high rate of mortality (32 

 percent) in these mature stands, chiefly of hemlock. Sec- 

 ond-growth sawlogs-size stands yielded three-fourths of 

 the net increment. Mortality in this class of timber was 

 not excessive, but there is growing concern over the possi- 

 ble effects of what is called the little-leaf disease, which is 

 causing heavy mortality in young shortleaf pine stands in 

 several counties of the piedmont. Despite intensive study 

 no definite conclusions had been reached by 1941 with 

 respect to its cause or possible methods of control. 



Species group and forest condition 



indent ! M*Mlfc 



Net 

 increment 



Softwoods: 



Sawlog size: 



Old growth 



M 



board feet 



163, 600 

 1, 334. 700 



345, 700 

 7,600 



M 

 board feet 



52, 300 

 103, 600 



32, 900 



700 



M 



board feet 



111 300 



Second growth 



1,231 100 



Under-sawlog size: 

 Second growth 



312 SOO 



Reproduction and clearcut 



6,900 



Total 



1, 851, 600 



189, 500 



1 662 100 







Hardwoods: 

 Sawlog size: 



Old growth 



219. 300 

 393. 400 



115,200 

 400 



42,300 

 33, 300 



15, 500 



100 



177,000 



Second growth.. 



360, 100 



Under-sawlog size: 



Second growth 



99, 700 



Reproduction and clearcut 



300 



Total 



728, 300 



91, 200 



637. 100 







All species. _- . 



2, 579, 900 



280. 700 



2, 299, 200 



Old-growth timber is more abundant in the hardwoods 

 and mortality lower; such stands produced almost three- 

 tenths of the net increment. A large part of this volume 

 is in good-quality bottom-land hardwoods in the Coastal 

 Plain. Nearly three-fifths of the net increment was in 

 second-growth sawlog-size stands. Many of the trees 

 contributing to this volume increase are rather inferior 

 in quality, particularly in the piedmont. Mortality is 

 not conspicuously high in any one forest condition, but in 

 all but old-growth stands losses are proportionately greater 

 in hardwoods than in pine. 



Net Increment of the Total Stand 



The 9 million standard cords of net increment of the 

 total stand shown in table 30 is slightly more wood than 

 that consumed in 1938 by all the pulp mills in the United 

 States. About 60 percent of the volume is softwood, the 

 proportion varying from 31 percent in the mountains to 68 

 percent in the Coastal Plain. The volume increase in 

 cubic volume of 630 million cubic feet was roughly 5 per- 

 cent of the national wood yield. The forests of the Coastal 

 Plain, occupying about one-half of the wooded land in the 

 State, produced 58 percent of the board-foot increment 

 and nearly 50 percent of the increment ol all sound trees. 

 The piedmont and mountain forests do not produce their 

 share of board-foot increment because a high proportion 

 of the stands are below sawlog size. In time they will 

 develop into productive saw-timber stands if they receive 

 fairly adequate management and are protected from ex- 

 ploitative cutting, fire, insects, and similar destructive 

 agencies. 



5° 



