LIFE HISTORY OF SHORTLEAF PINE. 19 



shortleaf pine into the oak and hickory type is particularly notice- 

 able. Fresh openings become fully stocked usually during the 

 first four years; and, normally, in the mixed pine-and-hardwood 

 type, groups of pure young pine of a few prevailing age classes are 

 numerous. 



SEED. 



The seed of shortleaf is very small, varying usually from 50,000 to 

 70,000 to the pound. The cones which produce them are among 

 the smallest for all pines — from 1^ to 2\ inches in length. They 

 persist on the trees for periods of about four years on vigorous shoots 

 to seven or eight years on suppressed portions of the crown. Ripen- 

 ing in early autumn, the seeds fall by the middle of November and 

 He dormant during the winter. Germination usually takes place 

 during March or April. In ordinary seed years the seed averages 

 50 to 60 per cent germination, varying quite widely below this stand- 

 ard in unfavorable seasons and with unhealthy or old-aged trees. 

 One tree 280 years old had a full crop of cones bearing apparently 

 good seed. The germinative power of shortleaf pine is retained to 

 a large degree for several years. Seed of the 1911 seed crop, kept at 

 ordinary living temperatures, gave 56.8 per cent germination in the 

 spring of 1914. The seedlings, however, were apparently somewhat 

 lower in vigor than those grown from fresh seed. 



The seed of the shortleaf has some advantages over seeds of other 

 species. A marked ability to germinate successfully in grass and 

 leaf litter, as compared with other southern pines, has been ob- 

 served. 1 This is in line with the inherent capacity of the species to 

 thrive on the lighter upland soils deficient in soil moisture. The 

 very small size of the seed gives it an advantage over larger seed 

 in quickly reaching mineral soil. By means of a relatively large 

 wing the seed is readily borne by the wind. A breeze will carry 

 seed a distance of from 2 to 5 times the height of the tree; and strong 

 winds will carry it from one-eighth to one-fourth of a mile. 



Seed is produced both abundantly and regularly. Full crops 

 occur at an average interval of about three years, with intermediate 

 or partial crops almost every season. In a typical region of the 

 Arkansas National Forest, during a period of 13 years commencing 

 in 1901, shortleaf pine bore four full seed crops, seven partial crops, 

 and failed entirely during two seasons. 2 The years of abundant 

 seed were 1902, 1907, 1910, and 1913; 1903 and 1909 were blank 

 years, and the others intermediate. Thrifty trees with good light 

 supply begin to produce seed at about 20 years. Exceptional trees 

 have been noted with cones at 16 years. In open or mixed forest 



1 Proceedings of the Society of American Foresters, Vol. V, No. 1, "Loblolly and Shortleaf Pines," by 

 W. W. Ashe. 



2 Record of seed crops determined by study of crowns in a large logging area, Womble, Ark. 



