주요(主要) 침엽수(針葉樹) 조림목(造林木)의 재질변이(材質變異)에 관한 연구(硏究)(I) - 잣나무, 낙엽송(落葉松), 편백(扁栢)의 해부적(解剖的) 성질(性質) -

Variations in Properties and Qualities of Major Plantation-grown Softwoods in Korea(I) - Anatomical Properties of Pinus koraiensis, Larix leptolepis, and Chamaecyparis obtusa -

In fast grown softwood, there are very large changes in material properties going outward from the pith to bark such as anatomical, physical and mechanical characteristics. Some of variations in anatomical properties with annual ring were then examined from Pinus koraiensis, Larix leptolepis, and Chamaecyparis obtusa, which are major softwoods of plantation in Korea. The large variations of annual ring width during young age of tree tended to stabilize after 25year through the transitional period in 17~23year. The ring density was 1.5~2.4 in 1~10year period, and 3.5~6.3 in 30~35year period, in which juvenile and mature wood were certainly assumed to be formed, respectively. Variations of tracheid length showed functional relationships with annual rings as logarithm. Demarcation between juvenile wood and mature wood could be 16~19year, which was determined from increase rate of tracheid length of 0.2%. Cell wall thickness increased with increase of annual ring even though large variations were observed as well. Variations of cell wall thickness within species were pronounced in latewood than earlywood. The increase of cell wall thickness from juvenile wood to mature wood was predominant in Larix leptolepis as 2.0times, and least in Chamaecyparis obtusa as 1.1 times. Cell diameters showed trends of increase during young age of 1~15year, and consistent afterward. The variations of cell diameter between radial and tangential direction were greater in latewood, and most pronounced in Chamaecyparis obtusa.