Freeze/Thaw of black spruce wood as studied by unilateral magnetic resonance and magnetic resonance imaging
- 1. University of New Brunswick, Faculty of Forestry and Environmental Management, Fredericton, Canada
- 2. University of New Brunswick, Physics, Fredericton, Canada
- 3. FPInnovations, Vancouver, Canada
This study examines the phase transitions of water in black spruce (Picea mariana Mill.) sapwood by unilateral magnetic resonance and magnetic resonance imaging. The goal is to observe and understand the behavior of water below 0°C in wood. The species studied presented one abrupt phase change that occurred around -3°C, which was attributed to the phase transition of free water. A more diffuse change occurred below -60°C which was attributed to a phase transition of bound water. A recently developed portable unilateral magnetic resonance instrument is demonstrated as a powerful tool in the study of water in wood. This portable magnet employed a bulk spin-spin relaxation time measurement that quantifies observable bound and free water in wood. Imaging is employed to verify the unilateral magnetic resonance results and to better understand realistic freeze/thaw behavior of log samples in the field. A ring boundary behavior during the thawing process was observed and likewise there are differences in the thawing behaviors of heartwood and sapwood samples.