In Pine 29 Forest Products Journal

machinability. Abstract Flakes 3 Inches along the grain. 3/8-inch wide, and 0.02 inch thick were machined from the taproots (with 6inch-high stump) and second logs at eight 31-year-old slash pines. Specific gravity (O.D. weight, green volume) of Items averaged 0.52; rootwood averaged 0.43 and decreased sharply with depth below ground. Forty-four-lb./cu. ft. structural-type particleboards were prepared with random orientation of flakes and 5 percent phenol-formaldehyde solids. StemWood boards were !tlffer (737.~ psi MOE) than rootWood boards (643.000 psi MOE). but bending strength was lower (4,800 psi MOR) for stemboards than for fOOtboards (5.500 psi MOR). MOE/MOR ratio was 155 for stemboards and 118 for rootboards. The two types of boards did not differ In nail-withdrawal reSstance (96 and 97 lb.). Internal bond of fOOtboards (114 psi) was almost double that of stemboards (60 psi); the difference was associated in part with the greater densification of rootwood (x 1.66) as compared with stenwood (x 1.36). Root flakes were more confomlable but had higher proportions of grain deviation and damaged surfaces. Rootboards had greater dimensional movement In both planes, greater soaked THE STUMP AND TAPROOT of pulpwood-size pines contain substantial quantities of fiber that are n<K recovered in present harvesting practice. Previous work (Howard 1913) b8s shown the amount of fiber in these portions to be 25 to 30 ~t of merd1antable stem dry weight in 22-year-old slash pines. Specific gravity is lower in rootwood than in stemwood, but the chemical