GROWTH AND UTILIZATION 



27 



George F. Burks 

 C. Edward Behre^'^ 



Essential to an appraisal of the timber situa- 

 tion is information on annual timber growth, 

 mortality, amount cut and used, and the volume 

 cut but left unused in woods and mills. In the 

 long run, our timber needs can only be met by 

 growing as much timber of desired species, size, 

 and quality as will be required. A comparison 

 of annual timber growth and cut gives one measure 

 of the adequacy of current timber growth. Analy- 

 sis of cut in recent years provides a starting point 

 for estimating the size of needed future timber 

 crops. Knowledge of present losses from fire, 

 insects, disease, and other causes gives some 

 indication of the extent to which better protec- 

 tion and management may augment the available 

 timber supply in future years. And study of 

 unused woods and plant residues challenges 

 technological progress to make the timber we cut 

 go further. 



This section presents the available data on 

 current annual growth. It summarizes informa- 

 tion on mortality, the nature, causes, effects, 

 and control of which are discussed in the section 

 on Forest Protection. It analyzes timber pro- 

 ducts output in 1952, and translates this output 

 into the amount of growing stock cut or killed 

 in logging. It then compares timber cut and 

 growth in 1952. Logging and plant residues are 

 analyzed to show their quantity, character, and 

 source, and to ascertain the extent to which they 

 are being utilized. Finally, trends in timber 

 utilization are appraised to throw light on possi- 

 bilities for better and more complete use of grow- 

 ing stock, greater use of cull and dead trees, 

 reduction of plant residues, and better and more 

 complete use of them. 



Pertinent to the analysis throughout is the role 

 of sawtimber in the Nation's timber economy. 

 Currently, about 84 percent of the timber cut is 

 from sawtimber, and there are strong indications 

 that sawtimber will continue to pla}" about the 

 same relative role in our timber-product needs 

 of the future. Therefore, sawtimber is more 



prominently featured in the discussion of the 

 growth and utilization characteristics of the 

 timber situation than is growing stock. 



The United States is passing from the era in 

 which its needs for timber products could be met 

 by cutting the abundant supply of virgin timber. 

 We now know that timber for future needs must 

 be grown as an annual crop from the soil. Since 

 timber crops require 3^ears to mature, we must 

 take steps now to assure ample future supplies. 



ANNUAL TIMBER GROWTH AND 

 MORTALITY 



Annual Timber Growth 



As with any other crop, the timber that can 

 be harvested year after year is limited by the 

 amount that is grown each year. But with 

 trees, the harvest in any year does not consist of 

 the timber grown that year. It consists of the 

 accumulated growth of many years in the trees 

 that are cut. So, if we are to have a dependable 

 harvest, we must develop and sustain a stock of 

 standing timber in a succession of age classes 

 which will permit the cut to be taken each year 

 in trees of the needed sizes and which, in the 

 aggregate, will have sufficient net annual growth 

 to offset the needed cut. 



In the following discussion, annual growth 

 means the net change in volume of timber for a 

 specified year from causes other than cutting. It 

 includes growth of the timber on hand at the 

 beginning of the year, plus the total volume of 

 young timber reaching poletimber or sawtimber 

 size during the year (commonly referred to as 

 ingrowth), minus the mortality occurring during 

 the year. 



As used in this report, annual growth differs 

 from growth as defined in the 1945 Reappraisal 

 project in that it is net growth ^^ exclusive of 

 losses from fire, disease, msects, and other causes. 

 On the Reappraisal project, all losses from fire. 



2' The text and included tables deal chiefly with regional, 

 sectional, and national data. More detailed statistics, 

 including data for individual States, are presented in the 

 appendix, p. 499. 



"» Mr. Behre retired Oct. 1, 1955. 



2' For those interested in determining gross growth, it 

 can be derived by combining net growth and mortality 

 estimates presented in the following tables or from tables 

 presented in the appendix. 



145 



