Solid Wood Products 



SPECIES GROUPINGS 



2617 



Specialists in pallet design are not unanimous in grouping species according 

 to their serviceability in wooden pallets. Generally the classifications are based 

 on specific gravity of the woods, but designers are more immediately concerned 

 with modulus of rupture, modulus of elasticity, impact strength, and nail- 

 holding capability. In 1980 the hardwood species groupings recognized by the 

 National Wooden Pallet and Container Association were based on wood specific 

 gravity, as follows — ^by common name: 



Class A Class B Class C 



(lease dense) (medium) (most dense) 



Pallet purchasers usually specify species according to these classes, and specify 

 dimensions and size independently. 



The U.S. Department of Defense (1959) established four species groups as 

 follows, listed by common name: 



STIFFNESS AND RIGIDITY OF 48- BY 40-INCH NAILED PALLETS 

 OF 22 PINE-SITE HARDWOODS« 



Stem (1978) evaluated five laboratory-constructed pallets (fig. 22-31) of each 

 of 22 pine-site hardwood species for stiffness and rigidity. The pallets were non- 

 reversible, double-face, flush, four- way, 48- by 40-inch, with three notched 

 stringers. The lumber was sawn from logs 7 to 17 feet in length measuring 6 to 

 18 inches in top diameter. Logs for seven of the species were obtained from 

 central Louisiana (small logs from southern pine sites), and the balance from 

 Virginia (somewhat larger logs). The lumber was planed while green to the 



^Condensed from Stem (1978). 



