Abstract:

A series of solvent-exchanged treatments (by means of ethanol, acetone and pentane in different concentrations), and air-dried treatment, were made on the greenwood specimens from 5 trees of Chinese Fir (Cunninghamia lanceolata) and 5 trees of Masson Pines (Pinus massoniana) plantation. The permeability of these solvent-exchanged and the air dried specimens of both heartwood and sapwood were measured by means of rising water displacement method. The results showed the average permeability of the solvent-exchanged specimens of the heartwood and sapwood both in common Chinese Fir and Masson Pine were higher than those of the air dried respectively. The permeability of heartwood of the solvent exchange dried common Chinese Fir was 2.16×10^-12m³·m^-1, while that of air-dried was 0.11×10^-12m³·m^-1, 19.7 times smaller than the former. The permeability of sapwood of the solvent exchange dried common Chinese Fir was 4.72×10^-12m³·m^-1, while that of air-dried was 0.99×10^-12m³·m^-1,4.7 times smaller than the former. The permeability of heartwood of the solvent exchange dried Masson Pine was 0.39×10^-12m³·m^-1, while that of air dried was 0.17×10^-12m³·m^-1, 2.3 times smaller than the former. The permeability of sapwood of the solvent exchange dried Masson Pine was 5.31×10^-12m³·m^-1, while that of air-dried was 0.84×10^-12m³·m^-1, 6.3 times smaller than the former. The permeability of sapwood of both air dried and the solvent exchange dried specimens were bigger than the heartwood. Within tree comparison showed the average permeability of almost all of the sapwood of solvent exchanged specimens was higher than that of the air dried, while most of the solvent exchanged heartwood was higher than that of the air dried despite some has no change or even lower.

Key words: Permeability, Heartwood, Sapwood, Solvent-exchange drying, Air drying