LIFE HISTORY OF SHORTLEAF PINE. 



29 



Table 9. — Height growth of shortleaf pine, based on age, in Arkansas and North 



Caro Una — Continued . 







PIEDMONT REGION 



NORTH CAROLINA. 









Height. 



Age (years). 



Height. 



Age (years). 



Maximum. 



Average. 



Minimum. 



Maximum. 



Average. 



Minimum. 



5 



Feet. 

 22 

 48 

 63 

 69 

 71 

 73 

 74 

 75 



Feet. 

 13 

 29 

 42 

 50 

 57 

 61 

 63 

 65 



Feet. 



45 



leet. 

 75 



76 

 76 



77 

 77 

 77 

 78 

 78 



Feet. 

 67 

 68 

 69 

 69 

 70 

 70 

 70 

 71 



Feet. 



40 



10 



10 

 15 

 20 

 25 

 29 

 33 

 36 



50 



55 



43 



15 



45 



20... 



60 



65 



48 



25 



49 



30... 



70 



75 



51 



35 



53 



40 



80 



55 









During early life the terminal leader of shortleaf pine commonly 

 forms from two to four secondary or false terminal nodes during the 

 growing season. These are accompanied by false rings of growth in 

 the wood, usually plainly marked and apt to be mistaken for true 

 rings. 



The influence of side light upon height growth is well illustrated in 

 figure 5, showing a 10-year-old stand of shortleaf with the east and 

 west side light cut off by an adjacent stand. The heights increase 

 from 2 feet near the margin to 22 feet under full fight. This illus- 

 trates very well the need of light for development, and, at the same 

 time, the power of endurance of shortleaf under limited light supply. 

 A 9-year-old stand with 3,800 trees per acre averaged 19 feet high 

 as compared with only 16 feet for a near-by stand of the same age 

 and on similar soil with 12,200 trees per acre. Two adjacent young 

 stands, similar in all points except tree density, averaged 9 feet high 

 for 4,100 trees per acre and 5 feet high for 32,000 trees per acre. 



DIAMETER. 



The rate of diameter growth of shortleaf pine is intermediate be- 

 tween that of loblolly and that of longleaf pine, the slowest of the 

 important southern pines. Besides the well-defined annual rings of 

 wood which clearly record diameter growth, from two to four ter- 

 minal nodes in the stem of the tree, accompanied by slight resting 

 periods in the tree's activity, usually occur during the period of 

 vigorous growth in earlier fife. These growth periods are recorded by 

 fine lines of denser wood within the true annual rings. Periods of 

 injury, caused by insect attack, fire, or severe drought during which 

 growth is temporarily checked, usually have the same effect. Such 

 fines, forming false rings, are frequent in shortleaf pine, and must be 

 distinguished in examining a cross section for age. Prominent bands 

 of wood stained brown in color are particularly apt to be found in 



