처리 온도에 따른 90 × 90 mm 낙엽송 각재의 재색 차이 조사

Investigating the Color Differences of 90 × 90 mm Larch Squares Heat-treated at Various Temperatures

To make value-added products from small-diameter larch logs it is necessary to reduce the color variation between boards. The effect of heat treatment on the color variation was investigated. Four hundred air-dried larch squares were visually classified into six groups. The largest color difference index between them was 8.8. When they were kiln-dried lower than 120°C, their average color difference indexes decreased to less than 6.0 compared with the air-dried. However statistical analyses revealed that kiln-drying largely increased the variation of the indexes of the color elements. Heat-treatment above 150°C increased the color difference in-dexes with the increase of temperature. The variation of color difference indexes within a group at 190°C were less than the groups at 150°C and 170°C. It implies that heat treatment at 190°C could make the color of larch squares uniform.