SHORTLEAF PINE: IMPORTANCE AND MANAGEMENT. 7 



pounds, but varies in accordance with the moisture content, which 

 ranges from 12 to 18 per cent. Green shortleaf in the log averages 

 45.5 pounds per cubic foot, with a moisture content of 31 per cent for 

 heart and 88 per cent for sapwood. The loss of weight in drying 

 amounts to about 25 per cent for the heartwood and about 60 per cent 

 for the sapwood. In passing from a green to an oven-dry condition 

 the wood shrinks about 12 per cent in volume, about one-third of 

 which occurs in passing from the green to the air-dry (15 per cent) 

 condition. The density of absolutely dry wood is variable, its specific 

 gravity being from 0.48 to about 0.56. 1 This difference in density 

 seems largely due to the varying conditions of growth over its wide 

 geographic range. 



In resin content shortleaf ranks lower than longleaf pine and 

 about the same as loblolly, although all are variable, and the amount 

 of difference has not been definitely determined. When the sapwood 

 of shortleaf is freshly cut limpid resin oozes out freely. Occasionally 

 the heartwood and normally the bases of all large limbs become 

 highly impregnated with resin and furnish " lightwood " and " pine 

 knots," extensively used for firewood. In fuel value shortleaf aver- 

 ages about 12 per cent below longleaf, of which 1 cord is approxi- 

 mately equivalent to a ton of coal. This is largely due to the differ- 

 ence in the average density of the two woods. For woods of the 

 same weight per cord of the two species it is believed there is little 

 difference, if any, in heat producing power. 2 



The wood varies somewhat in hardness, and in some regions is 

 moderately soft. In its southern range it averages about as hard as 

 longleaf pine when there is the same proportion of summer wood 

 in the annual rings. The wood grown in the more northern regions 

 or at higher altitudes in the southern region seems to be softer. 



The width of the rings is greatest in early life. Ten to twelve 

 rings to the inch is an average rate of growth during the middle 

 period, say from 60 to 140 years. Within the individual annual 

 ring, the transition from the spring to the summer wood is normally 

 quite abrupt, giving the annual ring the appearance of two sharply 

 defined lines or bands. In young and rapid-growing trees and in 

 those growing where the summers are short, the transition is com- 

 monly more gradual. 



Since the fibers are straight and do not interlock, the wood is 

 straight grained, easy to split and but slightly subject to warp and 

 check in drying. 'Hie wood is easily worked, may be given a good 

 finish, and ti\\«-.-: paint ;md wood preservative well. The contrast 



1 Latter figure n<>i definitely determined. 



- i'on-si Products Laboratory, Madison, WIh. 



