Raw material characterization and properties of structural flakeboard from coppice grown hybrid poplar

Tree growth variables and properties of the wood and bark were evaluated for 3-year-old coppice grown hybrid poplar. Three clones (NE-5323, NE-5326, and NE-5377) from a Populus x euramericana cross, each growing at 5,000, 10,000, and 15,000 stems/ha were studied. This material was then used for the manufacture of 40 lb/ft(\u273) homogeneous flakeboards in an attempt to evaluate the effects of the raw material quality on properties of flakeboard;Height, diameters at one foot and 4.5 feet, the proportions of stem and branch material, and the number of sprouts per stump were significantly different among all clones and planting densities. Clone NE-5323 had the best overall height and diameter growth. Height and diameter growth for all clones was greater than that reported for first rotation 3-year-old hybrid poplar. The proportions of stem material and the number of sprouts per stump decreased with increasing planting density;Wood and bark specific gravity, wood fiber length, vessel segment length, bark fiber length, the proportions of cell types (i.e., fibers, vessels, rays, parenchyma), the proportion of bark, and bark thickness were also determined from the single, dominant coppice sprout of each tree. Planting density did not have a significant effect on any of these characteristics. The wood and bark quality of clone NE-5323 was superior to the other two clones. Partial correlation coefficients among all characteristics were calculated;Moduli of elasticity and rupture in bending, internal bond, thickness swell, linear expansion, water absorption, and strength properties after accelerated aging were determined for homogeneous flakeboards made from material from each clone and planting density;No significant differences in any strength or dimensional stability properties could be attributed to clone or planting density effects. Compared to the properties of flakeboards made from material from the main stem only, strength and dimensional stability properties were significantly less for flakeboards that contained main stem and branch material