118 TIMBER PINES OF THE SOUTHERN UNITED STATES. 



For well-seasoned wood, the following figures represent the average of hundreds of tests on 

 specimens specially collected lor this purpose: 



Lbs. per sq. inch. 



Mod ulus of elasticity 1 , 950, 000 



Trausverse Ktrciigth 10, 100 



Compression oudwise 6,500 



Sliearing witli tlie fiber 600 



Since the average weight of the test pieces was 40 pounds jxt ciiljic loot, 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 tlie 

 green lumber loses a large amount of water, dependent chiefly on the proportion of sai)\v()od. 

 Though (|uit(' variable, the water in fresh sapwood commonly forms 50 to GO per cent of the weight, 

 while in heartwood it little exceeds 25 per cent. 



The shrinkage conse(inent 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 wliich appears due to the difference iu the 

 weight of the wood of the different sections. As in other pine, about two-tliirds or seven-eights 

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

 to the radius. 



In kilndrying, the wood maybe taken fresh from the saw and behaves extremely well, sixflfering 

 no great injury, a fact whicli has greatly euhaneed 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 (•oi)ionsly dispersed over the 

 vicinity of the mother trees by the wind, the offspring quickly taking possession of old fields and 

 clearings in the forest. 



The seeds germinate in the eaily si)ring. The ends of tlie cotyledons remain for a short time 

 after germination inclosed in the endosperm. The nund)er 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 iu length. The rootlets are half that length, 

 and are provided with several acro[)etal secondary rootlets. The caulicle gi-ows rapidly, and is 

 soon covered with the still', tieedle sliajH'd, and strongly serrulated primary leaves. Belbre the 

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

 tiie axils of tlie former. At the close of tlu! summer season the jilantlet has attained a height of 

 from to S inches, the upper i)art of the stem covered with foli;ig<> leaves, tlie acerose jirimary 

 leaves of the lower iiart 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 subsccpieut 

 stage of the growtii. With the second year the primary leaves have all beconu^ reduced to the 

 ordinary form of the leaf bra(!t — lauc(M)late, acuminate, with 11 inbriate 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 session, 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 iu height. 



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

 one-fourth to (ive-sixteentlis of au inch in thickness. The branches, forming regular whorls, are 

 erect and i)roduce in their turn whorls of secondary order. The root system shows a correspond- 

 ing increase, the taproot being from (! to 8 inches huig, with numerous stout lateral roots. 



KATE OF GKO^VTII. 



With the fourth year the Loblolly Fine enters seemingly upon the period of (piickest growth. 

 As ascertained by many measurements, tlie trees at the end of tiieir fourth year average .'? feet in 

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

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



