38 LOBLOLLY OK NORTH CAROLINA PINE. 



Crown. 



Braiichlets are commonly borne in whorls of three. They develop 

 not only at the tip of the leader, but also at intermediate points along 

 the season's growth, the growth of the leader being recrudescent. In 

 young rapidly-growing trees there are usually three whorls and conse- 

 quently three internodes on the leader in one season (Plate II). Al- 

 though the nodes may be close together in loblolly pine, the knots in the 

 tree may be distant and irregularly distributed, as not all branchlets in 

 a whorl develop into branches. 



The crown of the young thrifty growing tree is sharply conical, the 

 rather slender arched branches ascending at an angle of 45 degrees or 

 more. At middle age the crown becomes oval, and in old age broadly 

 oval and flat-topped; the wide spreading branches become stout, irregu- 

 larly distributed, and nearly horizontal, with tips slightly ascending. 

 (Plate I.) 



Root System. 



The root of the one and two-year-old seedling pine is fibrous and 

 diffuse; and, though the central slender taproot is very evident, it is 

 essentially a fibrous root system. (Figure 3, c.) With age, the taproot, 

 although it remains short, becomes proportionately more prominent, 

 and many deeply seated lateral roots are developed. The taproot, which 

 seldom descends to a depth of more than 4 or 5 feet, is often forked 

 and blunted, and on hardpan and heavy clay soils, flattened or curved 

 at the tip; it never assumes the proportion of that of the longleaf or 

 shortleaf pines nor descends to such a depth as do the taproots of those 

 trees. (Fig. 3, a. and &.) On loose, moist or sandy soils many of 

 the lateral and central roots are deep-seated, descending 3 to 5 feet, but 

 others lie near the surface of the ground. (Fig. 4, a and fe.) On compact, 

 and especially on dry, clay soils, the roots are much shallower and more 

 spreading. On very wet soils where the water table is prevailingly close 

 to the surface during the growing season there is in old trees no well 

 developed tap root, but its place is taken by a number of central spread- 

 ing roots. (Fig. 4, c.) The great development of the lateral roots 

 probably explains the rapid growth of the pine in old fields, where the 

 loose, easily penetrable top soils form an excellent bed for the spread of 

 such roots. The early culmination of the growth in old fields on the 

 red clays of the Piedmont, especially on the poorer soils, may be due in 

 part to the check in the development of the lateral root system, as the 

 roots fail to descend into the hard subsoil, as well as to the limited 

 supply of soil moisture available for the stand. In old trees on loose, 

 moist soils, the lateral roots spread for a distance of from 25 to 30 feet 

 from the tree, though the taproot is rarely more than three feet long. 

 The taproot is much shorter on compact clay soils and where there is a 

 hard pan than on loose soils. 



