| It is studies the conventional drying of C.japonica and C.lanceolata which are two important plantation softwood. The wood long is 80cm, and the diameter is about 20cm. The shrinkages, the drying characteristics, the drying process, the regular of moisture content and temperature in the drying process, and the mechanical properties have been analysed. The results: 1) The basic density change of C.japonica and C.lanceolata is similar. In the radial, the basic density of the heartwood is greater than that of the sapwood; In the longitudinal, the basic density of the sapwood increases from top to bottom, while the basic density of the heartwood reduces at the beginning then increases from top to bottom. 2) The shrinkage of C.japonica and C.lanceolata in tangential direction is greater than that in the radial. The shrinkage ratio of tangential to radial of C.lanceolata is higher than that of C.japonica, so in the drying process the wood of C.lanceolata is apt to warp and split easily. 3) During the high moisture process, the shrinkage coefficient is lower; the shrinkage coefficient is greater in the middle of the low moisture process. At the same time, the tangential shrinkage coefficient is greater than the radial shrinkage coefficient in the process of the same moisture process. 4) The drying schedule for C.japonica and C.lanceolata is formulated on the basic of 100℃condition. The initial checks of C.lanceolata is more serious than that of C.japonica. The drying characteristics divide five grades, the third which C.lanceolata and C.japonica are. 5) Because of the properties of the plantation of small diameter posts, the drying schedule is more soft than that of sawn timber. And it's important to strengthen the conditionging during the later stage. 6) The indexes examine drying quality including the longitudinal moisture content deviation, the radial moisture content deviation, the final moisture content, end check and wood drying stress. 7) In the drying process, the drying rate reduces clearly when the moisture content is 35% and 15%. 8) The temperature distribution in the wood is high on surface while is low in core. It is similar to swan timber dried. 9) The moisture content distribution in the round section can be represented in a parabola, which the surface is low while the core is high. After conditioning, the moisture content between the surface and the core is unanimous. 10) According to the examining indexes stress grade of structural lumber in the building, the mechanical properties of the two species meet the lowest demand, conforming to the mechanical demand of roof beans and posts. |
