FOREST 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 
