Effects of curvature in hybrid poplar on acoustic velocity at the tree level
1 Département des Sciences du Bois et de la Forêt, Université Laval, Québec, Canada
2 Waiariki Institute of Technology, Rotorua, New Zealand
New Zealand Journal of Forestry Science 2013, 43:7 doi:10.1186/1179-5395-43-7Published: 8 August 2013
Background and Methods
Measurements of stress wave velocity were performed with the Fibre-gen Director ST300 on 146 hybrid poplar (Populus sp.) plantation trees from GreenWood Resources Inc. located near the city of Boardman, Oregon USA. A laser scanner (Faro Focus 3D) was used to measure the curvature of the trees. Combinations of two software tools (Treemetrics Autostem and Sweep Extractor) were used to calculate the curvature for two log lengths (3 and 6 m) from a height of 10 cm above the ground. The propagation velocities of the stress waves were measured twice; first at breast height on the convex side of the stem and then at 90 degrees clockwise around the stem from the first measurement.
Results and Conclusions
Analysis of the data showed that there was no significant difference (p = 0.24) between propagation velocities when the probes were located on either the convex side or at 90 degrees to the convex side. However, the propagation velocity was significantly greater on trees with higher curvature, suggesting that the velocities measured with the ST300 can take into account the presence of reaction wood (tension wood) in the tree.