tended throughout the State and forestry practices 

 are more widely adopted. 



In 1936, two-thirds of the net increment (tables 24 

 and 35, Appendix) was in second-growth sawlog-size 

 stands, 16 percent in old-growth (equally divided 

 between uncut and partly cut) and the remaining 18 

 percent in sawlog-size trees scattered in under-saw- 

 log-size stands. Nearly half the total growth was 

 made by the forests in the northern Coastal Plain. 



Net board-foot increment by pines and hardwoods 

 varied widely among condition classes. For exam- 

 ple, 71 percent of the net growth of pine was in 

 second-growth saw-timber, and only 6 percent in 

 old-growth stands; while for hardwoods 52 percent 

 was in second-growth and 39 percent in old-growth 

 stands. 



Growth in Cubic Feet 



Measured in cubic feet, the gross annual growth 

 of all sound trees 5 inches d. b. h. and larger in the 

 5-year period 1936-40 (table 23) averaged 465 mil- 

 lion cubic feet, 63 percent in pine, and 37 percent in 

 hardwoods. Since over a fifth was lost by mortality, 

 the net growth amounted to 360 million cubic feet. 

 In the pine stands of the southern Coastal Plain the 

 loss reached 31 percent. As in the saw-timber 

 stands, the net cubic-foot growth made by pines and 

 hardwoods varied considerably between old-growth 

 and second-growth stands; hardwoods accounted for 

 nearly three-fourths of the cubic-foot increment in 

 old-growth stands but for less than a third in the 

 second-growth stands. 



The net growth of cull trees, and the tops of hard- 

 woods and cypress above sawlog limits, was not in- 

 cluded in the above figures. Rough estimates indi- 

 cate that it amounted in 1936 to 53 million cubic 

 feet, or about 15 percent of the total net growth of 

 sound trees. 



Theoretically, a volume equivalent to net growth 

 may be cut annually without continuing the deple- 

 tion of the growing stock, assuming that all sound 

 trees will be cut at some time. Actually the volume 

 available is somewhat less than the net growth, be- 

 cause some stands, as well as trees of the less desir- 

 able species, will probably never be cut. Moreover, 

 some of the trees should be retained to build up the 

 growing stock that is below a desirable level in most 

 stands. 



Net Growth Per Acre 



The average net growth per acre in 1936 by condi- 

 tion class and regional unit is summarized in table 



25. For the State, saw-timber stands in all condi- 

 tion classes averaged 131 board feet per acre, 71 per- 

 cent of which was pine and 29 percent hardwoods. 

 The average was 149 board feet on the northern 

 Coastal Plain, 107 feet on the southern Coastal 

 Plain, and 129 feet on the piedmont. For sawlog- 

 size trees, second growth averaged 200 board feet 

 per acre for all species, partly cut old-growth 118 feet 

 and uncut old-growth 163 feet. 



These figures indicate the growth that may be ex- 

 pected under the existing type of forest management 

 and as long as significant changes do not occur in 

 density. Management practices which lead to 

 better stocking and also reduce mortality will, of 

 course, result in greater increments per acre. 



Commodity Drain 



Commodity drain comprises the volume of wood 

 cut from growing stock, i. e., from sound trees 5 

 inches d. b. h. and larger. It does not include mate- 

 rial cut from dead and cull trees and from the tops 

 of hardwoods and cypress, or the wood imported 

 from adjoining States for processing in South Caro- 

 lina. 



After the Forest Survey's inventory of 1936, an- 

 nual records were maintained in order to keep the 

 data up to date. From these records table 26, show- 

 ing the actual drain on South Carolina's forests in 

 1936, 1938, and 1940, and Appendix table ?>(), indi- 

 cating the average annual commodity drain for the 

 5-year period 1936-40, have been prepared. The 

 drain on the sawlog material is expressed in board 

 feet and on all sound trees 5 inches d. b. h. and larger, 

 excluding bark, in cubic feet. 



Drain on Sawlog Material 



The average drain on trees of sawlog size during 

 the 5-year period 1936-40 was 1.3 billion board feet 

 a year. The drain was distributed as follows: 



Percent 



Lumber 58 



Fuel wood 19 



Pulpwood 8 



Veneer 7 



Hewn cross ties, poles, piles and miscellaneous 8 



Total 100 



Fifty-two percent of the drain was on forests in the 

 northern Coastal Plain, 26 percent in the southern 

 Coastal Plain, and 22 percent in the piedmont. 

 Pines supplied two-thirds of the sawlog drain (892 

 million board feet a year), principally for lumber, 

 fuel wood, and pulpwood; hardwoods and cypress 



49 



