LIFE HISTORY OF SHORTLEAF PINE. 



21 



EXTENT AND NATURAL LIMITATIONS. 



In open-grown, vigorous stands, shortleaf successfully coppices up 

 to about the eighth year, and in slow-growing, crowded, or shaded 

 stands, to the tenth or twelfth years. The upper limit of size at 

 which coppicing may take place ranges from diameters near the 

 ground of 3 to 4 inches for vigorous individuals down to 2 to 3 inches 

 for trees of slow growth. Thus the chief limitation seems to be age, 

 modified by the general vigor and size of the individual stem. 



Within these limits shortleaf is known to coppice repeatedly. 

 Regions of frequent fires afford opportunities to observe the effects of 

 repeated burning to the ground upon younger-aged stands. Figure 7 

 shows diagrammatically a fully stocked stand in Arkansas, composed 



m 



/6 

 /4 

 /E 

 /O 

 8 

 6 

 4 



Fig. 7. — Vertical section through three successive generations of shortleaf pine fire coppice. Pike County, 

 Ark. (Drawn from, actual stand.) 



of three successive generations of coppice resulting from fires in 

 1902, 1904, and 1910. Each age class was regular and normally 

 stocked. The heights averaged 17 feet for the 10-year-old, 11.5 for 

 the 8-year-old, and 2.5 feet for the 2-year-old stand. Similar suc- 

 cessive generations of coppice are commonly met throughout all the 

 shortleaf region. Around the margin of a young stand, surface 

 fires burn freely, fed by the better growth of grass and light dry 

 materials deposited by the wind ; while farther within the stand there 

 is less ground litter, and the shaded surface is often too moist to burn 

 in the cool season when fires prevail. 



The number of successive generations of sprouts that can be pro- 

 duced from an original parent seedling is not known. Young coppice 

 of the second generation of sprouts is readily identified under close 

 observation. It occurs abundantly except in old-field stands. Three 



