Study on Air-drying Characteristics of Taun Lumber and Air-dring Calendar(I)

타운 재목(材木)의 천연건조(天然乾燥) 특성(特性) 및 캘린더에 관한 연구(硏究)(I)

Air-drying tests were carried out on green taun (Pometia pinnata f glabra) for 25-mm and 50-mm thickness to elucidate drying characteristics on air-drying rate, time and defects in spring and air-drying calendar. The results of this study were as follows: 1. The air-dried lumber for 25-mm thickness from an initial average moisture content (MC) of $58.3{\pm}3.5$ percent reached 30 percent MC in 17 days, 25 percent MC in 24 days, 20 percent MC in 38 days and 15 percent MC in 84 days. 2. The air-dried lumber for 50-mm thickness from an initial average MC of $59.6{\pm}5.0$ percent reached 30 percent MC in 39 days, 25 percent MC in 55 days and 20 percent MC in 84 days. 3. Air-drying calendar that could be useful in estimating drying times for each month developed by the use of climatological data for Suwon. Total number of effective air-drying days during a year were 243.5 days and the major determinant of the effect air-drying days was temperature. 4. The air-drying rates for 25-mm and 50-mm coated lumber were slight1y slower than those of uncoated lumber. The number and total length of both end checks and surface checks for end coated lumber were less severe than those of uncoated lumber.