drain was occasioned by the manufacture of 

 lumber, 29 percent by cross-tie production, and 

 almost 10 percent each by fuel-wood and veneer 

 uses. Pine composed nearly 50 percent and cy- 

 press 32 percent. The total commodity drain in 

 all trees 5 inches and larger, including saw-timber 

 material, reduced to a common factor, amounted 

 to 75 million cubic feet (table 24). 



It is recognized that the commodity drain calcu- 

 lated for 1 934 is below what may be expected during 

 more prosperous years. Indications are that the 

 drain due to lumber manufacture in 1936 exceeded 

 that of 1934 by more than 50 percent, and it is 

 likely that some increase has taken place in other 

 commodities. It is difficult, if not impossible, to 

 predict the drain during the next 10 years because 

 of the difficulty of weighing the many factors 

 involved; but it might not be unreasonable to as- 

 sume that the average annual commodity drain 

 during the next 10 years will be 25 percent greater 

 than that in 1934. 



Comparison of Increment 

 With Commodity Drain 



Data representing the many factors influencing 

 the increment of the pines, hardwoods, and cypress 

 (table 20) and the toll which the many wood-prod- 

 ucts industries exact (tables 23 and 24) are here re- 



LONGLEAF AND 

 SLASH PINES 



LOBLOLLY AND 

 OTHER PiNES 



assembled for comparison and consideration of their 

 net influence upon the growing stock of northeastern 

 Florida (table 25, fig. 10). 



Table 25. — Comparison of increment ' with commodity drain 

 IN BOARD FEET (INTERNATIONAL J4-INOH RULE) 



Item 



Pine 



Hard- 

 wood 



Cypress 



All 

 species 



Growing stock, Jan. 1, 1931 -- 



M 

 board feet 

 2 6, 518, 300 



M 

 board feet 

 2, 645, 300 



M 

 board feet 

 2, 017, 800 



M 



board feet 

 11,181,400 



Growth.. 



+470, 900 

 -310, 400 

 -22, 600 



+113, 900 

 -45, 900 



+52, 100 

 -34, 900 



+636, 900 



Mortality . ... 



-391, 200 



Unusable volume 



—22, 600 











Net increment 



+137, 900 

 -210, 000 



+68, 000 

 -78, 800 



+ 17, 200 

 -136,400 



+223, 100 





—425, 200 







Net change in grow- 

 ing stock.. 



-72, 100 



-10,800 



-119,200 



-202, 100 



Growing stock, Jan. 1, 1935. 



6, 446, 200 



2, 634, 500 



I. VI-, i.HII 



10, 979, 300 



IN PUBIC 



FEET (INSIDE BARK) 





Growing stock, Jan. 1, 1934. 



M 



cubic feet 

 3 2, 159, 770 



M 



cubic feet 

 * 951, 320 



M 

 cubic feet 

 5 567, 990 



M 

 cubic feet 

 3, 679, 080 



Growth 



+115,810 

 -91, 550 

 -1, 560 



+42, 360 

 -21, 300 



+15, 080 

 -10,610 



+173, 250 



Mortality 



Unusable volume 



-123,460 

 -1,560 



Net increment 



+22, 700 

 -41, 930 



+21, 060 

 -12,670 



+4, 470 

 -20, 400 



+48, 230 





—75, 000 







Net change in grow- 

 ing stock 



-19,230 



+8, 390 



-15, 930 



-26, 770 



Growing stock, Jan. 1, 1935. 



2, 140, 540 



959, 710 



552, 060 



3, 652, 310 



Figure 10. — Comparison of board-foot ( International Y^-inch rule) 

 net increment and commodity drain in each forest condition, 

 1934. 



i Plus sign (+) indicates increase; minus sign ( — ) indicates decrease. 



2 Includes 22.6 million board feet in the butts of newly cupped trees not 

 shown in the inventory summarized in table 11. 



3 Includes lYz million cubic feet in the butts of newly cupped trees not 

 shown in the inventory summarized in table 15. 



* Does not include over 223 million cubic feet of tops and limbs of 

 hardwoods, of which 650,000 cubic feet is in special-use species included 

 in table 15. 



6 Does not include over 111 million cubic feet in tops and limbs of 

 sawlog trees included in table 15. 



In 1934 the total commodity drain on saw-timber 

 material exceeded net increment by more than 202 

 million board feet. On January 1, 1935, there 

 was, therefore, 1.8 percent less saw-timber growing 

 stock than on January 1, 1934. The correspond- 

 ing decreases in growing stock for pines, hard- 

 woods, and cypress were 1.1, 0.4, and 5.9 percent, 

 respectively. 



The principal factors responsible for these de- 

 creases — namely, inadequate stocking of the stands, 

 low growth and high mortality rates, and the out- 

 put of wood products — may vary greatly from 

 decade to decade. It is incorrect, therefore, to 

 project the present rate of decrease in growing 

 stock into the future and to predict the wiping out 

 of the forests by the end of some indicated period. 



37 



