A study of water exchange in wood by means of 2D NMR relaxation correlation and exchange

Two-dimensional T 1-T 2 1H NMR relaxation correlation spectra and T 2-T 2 relaxation exchange spectra for samples of spruce wood across the full moisture content range from 0% to >100% are presented. The T 1-T 2 spectra unambiguously identify water in different environments within the wood that overlap in the corresponding and more traditional one-dimensional T 1 or T 2 experiment. The T 2-T 2 spectra unambiguously reveal the presence of water exchange between the lumen and cell wall above the fibre saturation point in sapwood. An estimate is made of the exchange rate: 1/30 to 1/3 ms-1.