82 FORESTRY INVESTIGATIONS U. K. DEPARTMENT OF AGRICULTURE. 



growth eighteen one-hundredths of an inch. Henceforth the growth in height remains almost 

 stationary. A do/en trees trom one hundred to one hundred and fifty years old were found to 

 vary from 09 to V2o feet in height, with a length of trunk free from limbs of from GO to 6S feet and 

 from 19 to 27 inches in diameter at breast height. 



From tabulated records of growth it becomes evident that under similar conditions of soil 

 and exposure the rate of increase for the various stages of growth show but slight differences in 

 localities widely distant from each other. 



Soil and climate. — The loblolly pine prefers a moist ? cool, sandy, or light loamy soil, which if 

 not always moist, should have greater retentiveness for moisture than is required by most of the 

 other upland pines. It reaches its greatest perfection in the perpetually moist or fresh forest 

 lands with a soil of a sandy loam, rich in vegetable mold which border the swamps of the coast 

 region. The tree is not found on the porous highly silicious soils of the more elevated uplands, 

 where the longleaf pine almost exclusively prevails. It also avoids heavy clay and calcareous 

 soils of the uplands and the alluvial lands. 



The loblolly pine is a tree of austral regions confined to the humid belt of the austro -riparian 

 or Louisianian zone and the lower border of the Carolinian life zone, which on the Atlantic coast 

 follows quite closely the isothermal line of 50° F.j westward, in the direction of the Gulf coast, 

 the isothermal line of 00°. The mean temperature of the winter along the northern limit is about 

 45°, with the lowest temperature only occasionally falling below 10° F. This tree approaches the 

 Appalachian zone only under the influence of a peninsular clime between the Delaware and 

 Chesapeake bays. 



The loblolly appears to be indifferent to the wide differences in the amount of atmospheric 

 precipitation existing within the vast range of its distribution. Extending from Florida (isotherm, 

 70°) to the thirty-ninth degree of north latitude on the Atlantic coast (isotherm, 56°), it is found 

 of equal thrift on the Gulf shore, with its damp air and annual rainfall exceeding 6-1 inches, and in 

 the flat woods of Texas, where the mean annual precipitation is only one-half that amount, with a 

 mean of inches during the winter months. In fact, the loblolly pine is found most frequently 

 and is more widely distributed in the districts of lesser precipitation. It is certainly more 

 dependent on the supplies of soil moisture than upon atmospheric humidity. 



Relation to light and associated species. — This species is less exacting in its demands for direct 

 sunlight than the kindred species within its range. To this relation may be ascribed the success 

 which it achieves in the struggle for the possession of the soil with the shortleaf pine. Observing 

 this contest as it is going on between the competing species in the forest, the conditions of the soil 

 being equally favorable, the loblolly pine, under the cover of shade, outstrips the shortleaf pine 

 under the same conditions; and, on the other hand, where the sunlight has had unhindered access, 

 it gives way to its competitor, being then subjected to the disadvantage resulting from a speedier 

 desiccation of the soil. Through such influences it is that, under conditions seemingly equally 

 favorable to either one of these pines, now the one and now the other is found to predominate. 



In the deep forests covering the rich swampy lands of the coast regions, the loblolly pine 

 forms comparatively a small part of the rich and varied growth consisting chiefly of deciduous 

 trees, black gum, sweet or red gum, water oak, and mockernut, to which in the lower South the 

 magnolia, sweet bay, red bay, and Cuban pine are to be added. Although requiring less sunlight 

 than most pines, in the gloomy impenetrable shade of these dense forests the progeny of the 

 loblolly pine has no future, especially as these lands once cleared are devoted to tillage, being of 

 great agricultural value. 



On the lands of a poorer, more exposed soil in the maritime plain of the southern Atlantic 

 States, in Virginia and North Carolina, and in southwestern Texas, this pine forms more or less 

 compact forests. In these forests the tree is always succeeded by its own progeny, either in the 

 course of nature or after the artificial removal of the original forest growth. On the coast of 

 Georgia, in Florida, and in the coast plain of the eastern Gulf States, the loblolly pine is scattered 

 among the Cuban and the longleaf pine; there its second growth meets a formidable competitor 

 in the first named of these species. In the flat woods, deprived of drainage, the Cuban pine is 

 always found to vastly outnumber the loblolly among the young forest growth. In the upper part 

 of the great maritime pine belt the loblolly pine is frequently found among the mixed growth of 

 magnolia, Spanish, red, post, and blackjack oaks, mockernut and pignut hickory, shortleaf pine, 



