126 TIMBER PINES OF THE SOUTHERN UNITED STATES. 



For well-seasoned wood, tbe following figures represent tlie average of luindreds of tests on 

 specimens specially collected for this purpose: 



Lbs. pt-r sq. inch. 



Moilulus of elasticity 1,950,000 



Transverse strength 10,100 



Compression endwise ' 6, 500 



Shearing with the fiber 690 



Since the average weight of the test pieces was 40 pounds per cubic foot, being heavier than 

 the average weight of the wood, these figures must be taken about one-sixth lower than given 

 above to represent the true average for the wood of the species. 



Like the wood of most conifers, that of Loblolly dries easily and rapidly. In doing so the 

 green lumber loses a large amount of water, dependent chiefly on the proportion of sapwood. 

 Though quite variable, the water in fresh sapwood commonly forms 50 to (iO per cent of the weight, 

 while in heartwood it little exceeds 25 per cent. 



The shrinkage consequent on drying amounts to 11 to 12 per cent of the volume; is greater in 

 the lumber of the butt than in that from the top logs, varying in this respect from 13 per cent at 

 the butt to about 10 per cent in the top, a difference which appears due to the difference iu the 

 weight of the wood of the different sections. As in other pine, about two tliirds, or 7 to 8 per 

 cent, of this shrinkage falls to the tangent (i. e., is along the rings) and about 4 to 5 per cent to 

 the radius. 



For kiln-drying the wood may be taken fresh from the saw and behaves extremely well, suftering 

 no great injury, a fact which has greatly enhanced its value by facilitating its exploitation. 



For the details of wood structure, consult the comparative study by Mr. Roth appended to 

 these monographs. 



PROGRESS OF DEVELOPMENT. 



The crops of seed are produced quite abundantly every year and copiously dispersed over the 

 vicinity of the mother trees by the wind; the offspring quickly takes possession of old fields and 

 clearings in the forest. 



The seeds germinate in the early spring. The ends of the cotyledons remain for a short time 

 after germination inclosed in the endosperm. The number of the germinal leaves (cotyledons) is 

 mostly six, rarely seven. At the time of the unfolding of the cotyledons the lower (hypocotyle- 

 donary) part of the axis of the plant is about 1 inch in length. The rootlets are half that length, 

 and are provided with several acropetal secondary rootlets. The caulicle grows rapidly, and is 

 soon covered with the stiff, needle-shaped, and strongly serrulated primary leaves. Before the 

 spring season has jiassed the bundles of secondary or foliage leaves make their appearance in 

 the axils of the former. At the close of the summer season the plantlet has attained a height of 

 from 6 to 8 inches, the upper part of the stem covered with foliage leaves, the acerose primary 

 leaves of the lower part having completely withered. In examining a large number of young 

 plants never less than three leaves in a bundle have been found during this or any subsequent 

 stage of the growth. With the second year the primary leaves have all become reduced to the 

 ordinary form of the leaf bract— lanceolate, acuminate, with fimbriate white hyaline edges and tips. 



In all the specimens examined it was found that the growth of the main axis proceeded less 

 rapidly during the second season, but produced a regular whorl of from three to four lateral axes. 

 At the close of the second year the main stem rarely exceeds 10 inches in height. 



At the end of their third year the plants are from 18 to 20 inches high, the stem being from 

 one-fourth to five-sixteenths of an inch iu thickness. The branches, forming regular whorls, are 

 erect and produce iu their turn whorls of secondary order. The root system shows a correspond- 

 ing increase, the taproot being from (i to IS inches long, with numerous stout lateral roots. 



RATE OF GROWTH. 



With the fourth year the Loblolly Pine enters seemingly upon the period of quickest growth. 

 As ascertained by many measurements, the trees at the end of their fourth year average 3 feet in 

 height and from one-half to seven-eighths of an inch in diameter, and at the end of the fifth year 

 measure nearly 5 feet and from 1 to 1^ inches in diameter. At the beginning of the seventh year 



