﻿FOEEST MANAGEMENT OF LOBLOLLY PINE. 5 



height growth, which continues until the tree is about 40 years old, 

 loblolly pine has a long, broad, conical or ovoid crown. With increas- 

 ing age this gradually dies off at the bottom, and finally becomes 

 somewhat flat and irregular. 



In comparatively dense stands loblolly pine prunes itself rapidly, 

 because of its intolerance of shade, and develops long, straight and 

 clear boles which produce lumber of the best grades. In open stands, 

 on the other hand, large, wide-spreading lateral branches are devel- 

 oped, and knotty, low-grade lumber is the result. Comparatively 

 open stands characterize the dry soils, on which natural thinning is 

 more rapid and the trees produced are shorter and less clean-boled 

 than on moist situations. 



Growth and Yield per Acre. 



The rate of growth of loblolly pine varies considerably with the 

 quality of the soil. The different soils or sites on which it commonly 

 occurs may be conveniently grouped under three quality classes — 

 I, II, and III. 



Quality Class I comprises the richest soils, where the rate of 

 growth is most rapid. It includes the very fertile soils, usually rich 

 in organic matter, with a uniformly abundant supply of moisture, 

 but free from standing water, such as bottom land along the edges 

 of streams, ponds, and deep swamps, moist depressions and basins 

 and the very best old-field soils. 



Quality Class II includes the great bulk of soils on which the 

 species occurs. These are fairly moist and are found in broad stretches 

 of flat land between the bottoms and the uplands and in most of the 

 old fields. 



Quality Class III includes all poor and dry upland soils, both 

 heavy and light, dry and sandy flat-land soils and sand hillls, and 

 the poorest of wornout old-field land. 



Old growth loblolly trees occur almost exclusively as single individ- 

 uals or in small groups in mixture with other species. In second 

 growth following clean cutting and on abandoned fields, however 

 the species has a remarkable tendency to reproduce itself in pure, 

 even-aged, fully stocked stands. Table 2 indicates the rate of growth 

 of such stands and the trees composing them on the three qualities 

 of soil described, including the possbile yield in either cubic feet 

 or board feet at different ages. The cubic-foot yields are given for 

 trees 3 inches in diameter and over, either peeled or with the bark 

 on. The board-foot yields, which, of course, are not in addition to the 

 cubic-foot yields, but merely express the yield for the same stand in 

 another unit, apply when either all trees over 5 inches or all over 7 

 inches in diameter are counted. This table is based on measurements 

 taken of pure, even-aged, unmanaged, fully stocked stands, found 



