Studies on the relationships between wood properties and the quality of veneer and plywood of plantation poplars

Abstract

Summary In this study three poplar clones, grown on three different beaches of the Yangtse River, and at three different planting densities (3 m × 4 m, 4m × 5m, 5m × 6m) were used to study relationships between wood properties and the quality of veneer and plywood. The results show: (i) The variance of veneer thickness was highly significantly related to fibre width and the proportion of vessels and fibres; and significantly related to the fibre length, the thickness of the cell wall, the ratio of cell wall to cell cavity, the ratio of cell cavity to cell diameter, the length of vessels and the proportion of rays. (ii) The ratio of lathe check in veneer was highly significantly related to only the diameter of the cell cavity. (iii) The glue-bond strength of plywood was highly significantly related to the fibre length, the fibre width, the diameter of cell cavity, the thickness of cell wall, the ratio of cell wall to cell cavity, the vessel length, the tangential diameter of vessels, the microfibril angle, and the proportion of vessels and rays; and significantly related to the proportion of fibres. (iv) The variance of veneer thickness and the ratio of lathe check in veneer were not related to chemical properties, but the glue-bond strength was significantly related to the pH value of sapwood, and highly significantly related to the pH value of heartwood and the average pH value of sapwood and heartwood. (v) The variance of veneer thickness and the glue-bond strength of plywood were not related to physical-mechanical properties, but the ratio of lathe check in veneer was highly significantly related to the modulus of elasticity, and significantly related to the air-dry wood density.