80 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 



vigor of growth. By a number of measurements made at Cullman, north Alabama, of trees from 

 the openings in the forest, as well as from clearings, it was found that by the end of the fifth year 

 they had attained a height varying between 3 and 5 feet, rarely over, the stem being from five-eighths 

 to seven-eighths of an inch in thickness ; by the end of the sixth year, from G to 9 feet high and 

 from one-half to 2 inches in diameter; and at the tenth year, from 10 to 16 feet high and from 2 

 to 2 J inches in diameter. At the age of fifteen to twenty years, with a total height of from 20 to 30 

 feet and a diameter, breast high, of 4 to 5 inches, the crown of the tree occupies from one-half to 

 five-eighths of its height. Henceforth throughout the period of quickest growth its rate is greatly 

 influenced by conditions of light and soil. At the age of fifty years the height of the trees varies 

 between 40 and 60 feet and the diameter, breast high, between 10 and 14 inches. About this age, 

 or perhaps a short time before, the height growth begins to decline and the branches become 

 somewhat reclining below and spreading toward the top, and consequently the head of the tree 

 becomes more rounded in outline. Between the ages of sixty and seventy years the trees are from 

 50 to 70 feet high and from 12 to 15 inches in diameter, with the trunk clear of limbs for 30 to 

 rarely over 40 feet. From this period on the growth proceeds at a slower rate. On reaching its 

 one hundiedth year the tree has attained a height between 90 and 95 feet and a diameter of 

 from 16 to 19 inches at most. Having now passed its period of vigorous life, the growth is 

 henceforth insignificant. Between the ages of one hundred and twenty and one hundred and 

 thirty years trees were found 90 to 110 feet high and from 18 to 24 inches in diameter. The oldest 

 tree encountered in the measurements, with two hundred and eight rings of annual growth in 

 the stump, scarcely exceeded 109 feet in height and measured 24 inches in diameter. The largest 

 tree felled was 117 feet high and 25 inches in diameter, with one hundred and forty-three rings in 

 the stump. Occasionally trees are found of a diameter exceeding 3 feet, but such are exceptional. 



Soil and climate. — The shortleaf pine prefers a well-drained, light sandy or gravelly clay soil 

 or warm loam, even if deficient in the elements of plant food. Soils of this character which are 

 found widely prevailing over the undulating or broken uplands, if only of sufficient depth, will 

 produce this tree in greatest perfection. It avoids the strongly calcareous and the rich alluvial 

 soils, as well as purely siliceous, being dependent on the presence of a certain amount of clay by 

 which the mechanical condition of the soil is improved, rendering it more compact and more 

 retentive of moisture. That a purely sandy and highly porous soil is not favorable to this tree 

 is shown by the stunted growth of the waifs sometimes found in the openings of the forests of 

 longleaf pine on the sandy, arid uplands in the lower part of the coast pine belt. 



Distributed in its range over 10 degrees of latitude and exposed to wide differences of 

 temperature, it shows almost the same thrift of growth near its northern limits under the isotherm 

 of 50° F. and in regions where the thermometer falls to near 20° below zero as in lower latitudes 

 with a mean annual temperature of 64° F. It can, therefore, endure a considerable range of 

 temperature. 



The conditions of atmospheric moisture evidently exercise a much more decided influence 

 over its distribution, and, without doubt, upon its individual development. The tree is found in 

 greatest abundance and of best growth where, within the limits of its distribution, the annual 

 rainfall varies between 48 to 52 inches, is less frequent in the districts where the precipitation 

 exceeds 5(> inches, still scarcer where the annual rainfall averages below 44 inches, and entirely 

 wanting where this is less than 40 iuches. Hence it is found best developed in the upper part of 

 the Gulf States and west of the Mississippi Eiver in adjacent northern districts from the interior 

 of Georgia to northeastern Texas, where the most favorable conditions in regard to atmospheric 

 precipitation prevail. The tree seems to avoid the humid air of the coast along the Gulf, as well 

 as along the seashore of the Southern Atlantic States, nor does it ascend the mountains in these 

 States above an altitude of 2,500 feet 



Relation to light and associated species. — The shortleaf pine, like most pines, is a light-needing 

 species, being, however, less sensitive to a deficiency in this direction than the longleaf and Cuban 

 pines, which latter succumb in competition with the shortleaf pine. Originally the shortleaf pine 

 is found more or less associated with various oaks (Spanish oak, blackjack, scarlet oak, post oak, 

 and black oak), the mockernut and the pignut hickory, and more rarely with the chestnut, the 

 mountain oak, and the scrub pine. All of these species prefer the warm, lighter soils of the 

 Uplands. These companions of the shortleaf pine are joined in the lower Southern States by 



