Forest Products Laboratory

Title: Effect of press-drying on static bending properties of plantation-grown No. 2 loblolly pine lumber

Author: Stoker, Denise L.; Pearson, R.G.; Kretschmann, David E.; Tang, Yifu; Simpson, Bill

Date: 2007

Source: Forest products journal. Vol. 57, no. 11 (Nov. 2007): Pages 70-73

Description: The purpose of this study was to determine the effects of two press-drying treatments on the static bending properties of plantation-grown, No. 2 grade, 2 by 4 loblolly pine lumber. Specimens were divided into groups containing primarily juvenile wood or primarily mature wood. The groups were subjected to three drying method-temperature/pressure combinations: (1) kiln-drying at 116 °C (240 °F), (2) press-drying at 172 or 345 kPa (25 or 50 psi), and (3) press-drying at 177 or 210 °C (350 or 410 °F). Modulus of rupture (MOR), modulus of elasticity (MOE), work to maximum load (WML), and specific gravity (SG) were determined. The results showed no change in SG in relationship to press-dry treatment and no practical differences in both MOE and MOR between press-dried and kiln-dried specimens. The only significant change was a decrease in work to maximum load with press-drying at 345 kPa and 210 °C (50 psi and 410 °F), which was detectable only in the higher quality pieces. The results suggest that loblolly pine properties are far more affected by the presence of juvenile wood and the inherent defects associated with the No. 2 grade than by press-dry treatment. Further work is needed to determine the influence of press-drying on the SG of full-size lumber. We expect that any effects will be most noticeable in higher quality pieces.

Keywords: Juvenile wood, specific gravity, pine, drying, moisture content, lumber, moisture, bending stress, mechanical properties, elasticity, modulus of elasticity, loblolly pine, shrinkage, kiln drying, press drying, strength, bending strength, stiffness

View and Print this Publication (104 KB)

Publication Notes: 

• We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
• This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

 Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

Citation

Stoker, Denise L.; Pearson, R.G.; Kretschmann, David E.; Tang, Yifu; Simpson, Bill  2007.  Effect of press-drying on static bending properties of plantation-grown No. 2 loblolly pine lumber.   Forest products journal. Vol. 57, no. 11 (Nov. 2007): Pages 70-73.