LIFE HISTORY OF SHORTLEAF PINE. 



31 



Table 11. — Relation of tree density and diameter growth in 30-year-old pure stands of 

 shortleaf of varying densities, Arkansas National Forest. 1 



Prevailing diameter class 

 (inches). 2 



Tree den- 

 sity (trees 

 per acre). 



Decrease 



(trees per 



acre). 



Prevailing diameter class 

 (inches). 2 



Tree den- 

 sity (trees 

 per acre). 



Decrease 



(trees per 



acre). 



4 



800 

 720 

 640 

 560 





8 



475 

 390 

 300 

 210 



85 



5 



80 

 80 



80 



9 



85 



6 



10 



90 



7 



11 



90 









i Based on seven plots in the same stand of varying density, but having uniform soil conditions. 

 2 The diameter class having the largest number of trees in the individual stand. 



• VOLUME GROWTH. 



The merchantable contents of a tree obviously depends upon total 

 height and diameter taken at successive points along the stem. The 

 rise in percentage of the rate of increase in the volume of shortleaf 

 pine in common with most trees culminates at a comparatively early 

 age, considerably prior to the year of maximum production of wood 

 for the individual tree. Furthermore, the highest annual production 

 of wood is reached somewhat earlier than the production of saw 

 timber. In stands of relatively equal density those on the poorer 

 sites and near the margin of natural distribution reach the maximum 

 rate of volume production at a later age than similar stands on 

 more favorable sites and more centrally situated within the region of 

 distribution. For example, the individual trees in stands in Missouri, 

 West Virginia, and New Jersey apparently show the greatest annual 

 wood increment at about 70 years, but in North Carolina the culmi- 

 nation is reached at about 50 years, and in Arkansas at about 35 

 to 40 years. 1 . The contents in board feet and cubic feet of trees of 

 different ages, up to 80 years, for two qualities of site, are shown in 

 Table 12. 



Table 12. — Volume of shortleaf -pine in North Carolina, based on age for two site classes. 



[Based on diameter growth of 332 trees, and volume table. Stump height 

 1.5 feet for trees 17 inches and over.] 



, 1 foot for trees 6 to 16 inches; 





Saw timber. 



Solid contents. 2 



Age (years). 



Scribner rule. 



Doyle rule. 





Quality 

 I. 



Quality 

 II. 



Quality 

 I. 



Quality 

 II. 



Quality 

 I. 



Quality 

 II. . 



15 



Boardfeet. 

 51 

 100 

 147 

 186 

 221 

 251 

 275 

 296 

 315 

 331 

 345 

 357 

 369 

 381 



Boardfeet. 



Boardfeet. 



17 



50 



87 



125 



160 



191 



216 



237 



255 



271 



284 



295 



306 



316 



Boardfeet. 



Cubic feet. 

 13.5 

 24 

 34 

 43 

 50 

 56 

 61 

 65 

 69 

 72 

 75 

 78 

 80 

 82 



Cubic feet. 



20 



6 



23 



38 



51 



63 



75 



86 



96 



105 



113 



121 



129 



135 



3 



7 



11 

 17 

 24 

 32 

 39 

 46 

 53 

 60 

 66 

 73 

 79 





25 



6 7 



30 



10.3 

 13.8 

 16.7 



35 



40 



45 



50 



22.0 

 24.0 

 26.0 



55 



60 



65 



70 





75 



31.0 



80 







1 For volume tables of shortleaf pine based upon height and logs per tree, see a forthcoming bulletin on 

 the Importance and management of shortleaf pine. 



2 Total volume of stem, including bark, between stump and top diameter, outside bark, of 5.5 inches. 



