• Journal of the Korean Wood Science and Technology
• /
• v.26 no.4
• /
• pp.71-77
• /
• 1998

To elucidate chemical structure of the wood extractive, wood meal of Larix leptolepis Gorden was extracted with 95% ethanol for 72 hours. The extract was fractionated with organic solvents such as n-hexane, chloroform, diethylether, and ethyl acetate. From the hexane somble fraction of the extractives, a new diterpene compound was isolated and identified as 6-acetoxymanool or 13-hydroxy-8(17), 14-labddienyl-6-acetate by IR, $^1H(^{13}C)$-NMR and Mass spectrometry.

• Journal of Korean Society of Forest Science
• /
• v.79 no.4
• /
• pp.419-423
• /
• 1990

This study was carried out to investigate the cause of pith-damaged wood formation, the state of growth, and difference of chemical composition of Japanese Larix(L. leptolepis Gorden). 1. Larix grew normaly to 10 years, and the volume increment was 32.4%. But it was gradually decreased to 19.4% from 11 to 13 years that the heartwood damage was occurred. Therefore, the volume increment was decreased 13%. The decayed wood was formed from fire wound portion of bark by forest fire. The volume loss from pith-dagmaged wood occurred by forest fire was more than 20%. 2. On the ash content, heartwood(0.05%) and pith-damaged wood(0.08%) was lower than sapwood(0.29%). The difference of extractive contents are considered the reason. It is considered that this ash content difference is depend upon the extractive contents among sap, heart and decayed wood parts. Holocellulose contents were from 54.3% to 59.3% and there were no difference among heartwood, pith-damaged wood, and sapwood, On the pentosan contents, heartwood(6.3%) and pith-damaged wood(6.6%) were higher than sapwood. Lignin contents of pith-damaged wood was tower than heartwood (34.4%). This seems to weaken all kinds of wood strength.

• Journal of Korean Society of Forest Science
• /
• v.83 no.4
• /
• pp.512-520
• /
• 1994

To enhance the utilization of Larch(Larix leptolepis Gorden) wood, the sawdusts were tested as cultivating media for Lentinus edodes(Mori 290) by varying the composition of the media. The economic efficiency for producing mushrooms from larch sawdusts was evaluated. The results are as follows. 1. Larch sawdust was as much efficient as oak sawdust in the growth of the mycelia and production of good quality of oak mushrooms. 2. The mushrooms were able to be harvested starting six months after beginning the cultivation. No differences were found among the qualities of the mushrooms produced by various treatments. 3. The contents of lignin(28.6-28.7%) in the fresh sawdust of larchwood are higher than those in the residues of the used media(18.2%). But lignin content of 1% NaOH extracts(30.4-34.4%) in fresh sawdust of larch was lower than those in the residues(68.0%). 4. The production of mushroom was relatively high to be 29.7-31.5%(760-780g.)/2.5kg pack) of mushroom weight. The net profit estimated was 1,475Won per pack.

• The Korean Journal of Ecology
• /
• v.8 no.1
• /
• pp.15-19
• /
• 1985

A number of field surveys have been performed in larch (Larix leptolepsis) forest floor in which any seeding of this species never find ther. In laboratory work, aqueous extracts from leaves, roots and stems of larch were provided and used to bioassay. Among them, germination and seedling growth of selected species were the most inhibitory in leaves extracts. Though germiation percentage of a species showed high compared with control, its dry weight after a given period grown were clearly low. The results due to be considered by allelopathic effect. And syringic acid and p-hydroxybenzoic acid were identified by HPLC from larch leaves. It is assumed that these phenolic acids affect on other species as allelochemicals of larch.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.1
• /
• pp.25-33
• /
• 2002

Improvement of density profile and sound absorption capability of particleboard was attempted. Three types of hot pressing methods examined ; flat-platen pressing method (A-type pressing), hot pressing in forming box (B-type pressing), and hot pressing set up jagged caul in forming box (C-type pressing). The raw materials were larch(Larix leptolepis (S, et. Z.) Gorden) shavings, phenol formaldehyde resin, and the particleboard perforated with stair type. The physical and mechanical properties such as specific gravity, bending strength (MOR), internal bonding strength (IB) and sound absorption coefficients were examined. The results are summarized as follows : 1) The MOR and internal bonding strength of the board pressed in forming box were higher than those of flat-platen pressed board. 2) The minimum density to average density ratio in thickness direction which pressed in forming box showed about 923%, in the case of 35 mm commercial particleboard and 50 mm flat-platen pressed board, its values showed about 66.4% and 865% respectively. 3) Sound absorption coefficients of the particleboard perforated with stair type were higher than those of flat-plated pressed board and commercial particleboard.