8 BULLETIN" 244, U. S. DEPARTMENT OF AGRICULTURE. 
the upper portions of its range, where associated with short leaf, this 
difference in outline and internal branching of the crowns becomes 
striking and serves as a distinguishing characteristic. 
In keeping with the small, close crown are the short, slender leaves 
of shortleaf pine. The leaf characteristics, together with the cone, 
afford the best means of identifying the species. (Fig. 2.) Special 
notice of this is essential, because confusion prevails generally in dis- 
tinguishing the various pines. Shortleaf belongs distinctly to the 
two-leaf group of pines. On the more vigorous portions of the crown, 
however, three leaves in the bundle are not uncommon. The leaves 
are mostly 3 to 5 inches long, in some localities appearing en masse 
of a slightly bronzed or pale-green color, in contrast to the glaucous 
or blue-green color in other localities or regions. Short shoots and 
colonies of sessile leaf bundles are often scattered along the trunk 
and over the upper sides of the larger branches: These are found on 
the pitch pine of the North and the pond pine of the South ; but since 
they occur in none of the important southern timber pines except 
shortleaf, they serve practically as a characteristic distinguishing 
shortleaf from both loblolly and longleaf pines. The size of the cones 
(" burrs") aids in recognizing shortleaf when otherwise it might be 
confounded with loblolly pine, its most common associate in the 
lower soils. The small cones of shortleaf (from 1J to 2\ inches in 
length) when open on the tree appear to be about the size of pigeon 
eggs; those of loblolly (from 3 to 5 inches in length) about the size 
of duck eggs. The individual scales composing the cone in shortleaf 
are armed with slender, needle-pointed prickles, broken off more 
easily than the stouter persistent prickles of loblolly cones. The seed 
of shortleaf (described on p. 19) is likewise much smaller than that of 
loblolly pine. 
A difference in the bark of shortleaf and loblolly is readily per- 
ceptible up to the beginning of old age. The bark of loblolly is on 
the average thicker, more deeply furrowed and ridged, and somewhat 
darker in color than that of shortleaf. After maturity these differ- 
ences in bark become less marked, or disappear. 
RELATION OF CLEAR LENGTH TO CROWN. 
Measurements taken in shortleaf stands of average density show 
much regularity in the relation of the length of the living crown to 
the total height of the tree. In stands about 10 feet in height the 
depth of the canopy averages 5 feet, or one-half the height of the 
stand. Above this height the canopy gradually becomes propor- 
tionately shorter, until at 80 feet clear lengths of 45 to 55 feet are 
reached. This is from about 60 to 70 per cent of the total height, 
varying with different qualities of site. The crown is relatively 
longer, in proportion to the total height of the tree, on the poorer 
situations, and, conversely, the clear length of the stem is snorter. 
