Investigation of moisture transport in branch wood of Norway Spruce using NMR

Abstract

Two samples from a specimen of a Norway spruce (Picea abies (L.) Karst.) branch was prepared. One opposite wood (OW) sample and one compression wood (CW) sample. Several tests using nuclear magnetic resonance were performed on these specimens to study the motion of moisture through the branch wood. The T2-experiment shows that the fibre saturation point is at 20% moisture content (MC) for OW and 25% MC for CW. The profile experiment shows that both samples have higher concentration of free water at side towards the bark, with the OW sample having a dry spot in the middle. The diffusion-T2 experiment found the mean diffusion coefficient for the free water in the OW sample to be 10,19 * 10-10 m2/s and the CW sample to be 9,9 * 10-10 m2/s showing higher mobility than the water in Norway spruce, implying that the mobility of the bound water is significantly lower. As this test only tests one sample from one branch specimen further testing can increase the confidence in these results and testing OW and CW samples drilled out in other directions can give more data on the movement of moisture in branch wood of Norway spruce.