Hybrid poplar chips (6.35 mm square cross section) are converted to a 45–50 per cent mass yield of acetone soluble products when heated fairly rapidly to 330°C in the presence of water. Virtually no char or unconverted wood is produced at 330°C. Water (15%), carbon dioxide (6.4%), aqueous organics (8.5%), and carbon monoxide (0.4%) are also significant products. Element balances for carbon, hydrogen and oxygen are 86, 98 and 96%, respectively, based on total input, or 86, 80 and 75% based on the wood input.