Abstract
Fast growing Eucalyptus grandis W. Hill ex Maiden (EG), E. amplifolia Naudin (EA), Corymbia torelliana (F.Muell.) K.D.Hill & L.A.S.Johnson (CT), and Populus deltoides W.Bartram ex Marshall (PD) may be deployed in Short Rotation Woody Crop (SRWC) systems in the lower Southeastern USA, especially in Florida. To evaluate these species for possible use as medium density fiberboard (MDF) and other composites, 2.5 m logs of three EG clones, three PD clones, six EA progenies, four CT trees, and one P. tremuloides Michx. (PT) tree from northern Wisconsin as a control were characterized for basic wood properties before being chipped, pulped, and pressed into MDF. The chips were thermomechanically pulped (TMP) for a two-phase study of the factors expected to influence suitability for MDF production: wood characteristics, refining system, resin system, and MDF formation. Phase I used TMP and 4% phenol-formaldehyde (PF) resin to produce 17 MDF species/genotype batches (S/GB). Thickness Swell (TS), Water Absorption (WA), Internal Bonding (IB), Modulus of Elasticity (MOE), and Modulus of Rupture (MOR) were evaluated to: (1) assess within species and within tree variation, (2) relate basic wood properties to MDF potential, and (3) examine repeatability of MDF-making. There was considerable variation among and within species, but only minor within tree variation. Six of the seventeen S/GBs had superior physical and mechanical MDF properties. In Phase II, two of the six better performing Phase I S/GBs were evaluated, along with three average Phase I S/GBs. Phase II compared the effects on IB from using tube and drum blenders for resin application, the influence of using unscreened versus screened fibers, and the differences of using PF resin at 4% or 6% versus urea-formaldehyde (UF) resin at 8% or 12%. Overall, genetic variation among species, and particularly within these species, affected their potential for commercial MDF. Log specific gravity (SG), fines, MDF SG, and fiber length influenced MDF properties, as did refining and MDF-processing variables. Further study of specific processing requirements can optimize the potential of young EG, EA, PD, and CT genotypes for MDF and other composites.
Highlights
Short Rotation Woody Crop (SRWC) systems involving the fast-growing hardwoods EG, E. amplifolia Naudin (EA), CT, and PD may be implemented in appropriate portions of Florida and the lower Southeast
The analyses examined the effects of species, genotype, and/or log on medium density fiberboard (MDF) panel properties, with a significance level of 5%
A number of differences were noted for certain wood properties among and within the Florida-grown EG, EA, PD, and CT species/genotype batches (S/GB) (Table 3)
Summary
SRWC systems involving the fast-growing hardwoods EG, EA, CT, and PD may be implemented in appropriate portions of Florida and the lower Southeast. EG is grown and sold commercially in southern Florida for landscape mulch. EA may be grown from central Florida into the lower southeastern USA, while PD can be grown across much of the US. CT is used as a windbreak for vegetable crops and citrus in central and southern Florida. While these SRWCs have been shown to be suitable for some traditional products and for energy wood [4], little is known about their suitability for a wider range of value-added products
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
