Strength Properties of Wood Related to Trunk Injection of Tree Growth Regulators    (View PDF)

Therese A. Wasniewski, William R. Chaney, Harvey A. Holt and John F. Senft

Abstract: The strength properties of wood discolored by trunk injection of tree growth regulators (TGRs) were investigated. Sections of trunk 60 cm in length were removed from the boles of yellow poplar {Liriodendron tulipifera) trees 12 months after injection with Clipper or Cutless and from blue gum (Eucalyptus globulus) 44 months after trunk injection with Atrinal. Miniboards (2.5 x 2.5 x 40.6 cm) were cut with a band saw from one trunk section below and two trunk sections above injection sites in yellow poplar. Miniboards were taken only from one trunk section above injection sites in blue gum. Miniboards containing discolored and nondiscolored wood were cut from adjacent areas of the trunk sections of treated trees. Boards also were cut from untreated yellow poplar trees. The miniboards were planed to uniform dimensions and were tested in a Universal Testing Machine configured for beam bending stress on a 35.6 cm span. The stiffness (modulus of elasticity) and the breaking strength (modulus of rupture) of each of 216 samples of yellow poplar and 14 samples of blue gum were determined. Discoloration of yellow poplar and blue gum wood associated with injection of TGRs did not reduce wood strength or elasticity.

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https://doi.org/10.48044/jauf.1993.035