• Journal of the Korea Furniture Society
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• v.23 no.4
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• pp.460-466
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• 2012

This study was conducted to investigate the surface hardness of thermally-compressed larch wood by compression set and temperature. The surface hardness of thermally-compressed larch wood increased with increasing compression set and temperature. For compression set 60%, the specific gravity was increased as 0.93. However, the surface hardness was lower value as 31.1 N/$mm^2$ compared with a similar specific gravity of the tropical timber. For density profile, less than compression set 40%, compression was observed mainly surface area. On the other hand, more than 50%, density profile variation was reduced by compression of central part. Results of this study indicate that thermally-compressed larch wood can be replace some imported hardwoods such as oak or cherry. However, thermally-compressed larch wood was difficult to replace the tropical timber being imported in terms of surface hardness.

• Mycobiology
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• v.32 no.4
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• pp.190-193
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• 2004

Six strains of Sparassis crispa such as S. crispa DUM-01, DUM-02, DUM-03, DUM-04, DUM-05, and DUM-06 were tested for their mycelial growth on 6 different kinds of sawdust media and primordial formation on 10 different compositions of larch sawdust media. The highest mycelial growth was recorded on the larch sawdust. Of the 6 strains of S. crispa, S. crispa DUM-04 recorded the favorable formation of primordia. The primordial formation of S. crispa DUM-04 was more favorable on L-3 medium than 9 kinds of larch sawdust media. When S. crispa DUM-04 was cultured on the media of larch sawdust+pine sawdust, the formation of its fruiting bodies was more outstanding on the media of larch sawdust+pine sawdust than those of larch sawdust.

• Journal of the Korean Wood Science and Technology
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• v.24 no.1
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• pp.34-47
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• 1996

Veneers of two nominal thicknesses, 1.5 and 2.5mm, were rotary peeled from Japanese larch (Larix leptolepis). Dahurian larch (Larix gmelinei) and Radiata pine (Pinus radiata) bolts unheated and heated in the water vat temperature of $66^{\circ}C$ by rising a final temperature at 10cm core of $60^{\circ}C$ to remain core diameter of 11.4cm. 1.5 and 2.5mm thick veneer cut from the heated Japanese larch were significantly thinner than those of the unheated bolt and 2.5mm thick veneer cut from the heated Dahurian larch were significantly thicker than that of the unheated bolt. 1.5mm thick Dahurian larch veneer and 1.5 and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts, respectively. Check distance on the loose side of 1.5mm thick veneer cut from the heated Radiata pine was significantly wider than that of the unheated bolt. However check distances on the loose side of 1.5 and 2.5mm thick Japanese larch and Dahurian larch veneers and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts. Also the depth of check on the loose side of three species showed insignificantly difference between the unheated and heated bolts. Arithmatic mean deviation($R_a$) and maximum height($R_{max}$) of the profile on the loose side of dried veneer by preheating the bolt compared with unheated bolts were different among apecies and between veneer thickness. The preheating treatment slightly affected qualities of these thin veneers such as 1.5 and 2.5mm. The yield of 2.5mm thick veneer from the heated radiata pine was significantly higher than that of the unheated bolt. However the yield of 2.5mm thick veneer for other two species and 1.5mm thick veneer for three species showed insignificant difference between the unheated and heated bolts. The yield of 2.5mm thick veneer for three species were higher than those of 1.5mm thick veneer. The average yields of green veneer of Japanese larch. Dahurian larch and Radiata pine were 57.1, 55.1 and 54.0 percent, respectively. Variables such as initial MC. drying time and veneer thickness had strong effect for Japanese larch veneer, less effect for Radiata pine veneer and nuch less effect on final MC for Dahurian larch veneer in jet drying. Correlation between the current MC and the drying time of Dahurian larch with low variation of initial MC was higher than those of Japanese larch and Radiata pine veneer with high variation of initial MC in high temperature drying. Thickness shrinkages of 2.5mm thick veneer for Japanese larch and Radiata pine were higher than those of 1.5mm thick veneers, but shrinkages of Dahurian larch veneer were similar between two nominal veneer thicknesses.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.381-389
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• 2015

In this study, the effects of moisture content and particles size of ground particles of torrefied larch chips on the pelletizing process were investigated depending on torrefaction conditions ($220^{\circ}C$-50 min, $250^{\circ}C$-50 min, $250^{\circ}C$-120 min). The moisture content in the torrefied chip decreased to 0.69~1.75%, while ash content and calorific value increased compared to untreated chip. In addition, weight loss significantly increased during torrefaction due to hemicellulose degradation. The carbon content in torrefied larch chip increased compare to untreated larch chip, while the hydrogen and oxygen contents decreased. The lignin and glucan contents in torrefied larch chip increased with increasing severity of the torrefaction condition, while hemicellulose decreased. In the particle size distribution of ground particles of torrefied larch chip, larch torrefied at severe conditions was found to produce smaller particles (~1 mm) than that of the larch torrefied at mild conditions. Macropore (over $500{\AA}$) in the torrefied particle was produced during torrefaction. During the pelletizing using ground particles of torrefied larch chip, the pressure needed in pelletizing decreased and pellet length increased with increasing moisture content, regardless of the particle size.

• Asian Journal of Atmospheric Environment
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• v.6 no.2
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• pp.104-110
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• 2012

We studied the effects of elevated ozone ([$O_3$]) and $CO_2$ concentrations ([$CO_2$]) on the growth and photosynthesis of the hybrid larch $F_1(F_1)$ and on its parents (the Dahurian larch and Japanese larch). $F_1$ is a promising species for timber production in northeast Asia. Seedlings of the three species were grown in 16 open top chambers and were exposed to two levels of $O_3$ (<10 ppb and 60 ppb for 7 h per day) in combination with two levels of $CO_2$ (ambient and 600 ppm for daytime) over an entire growing season. Ozone reduced the growth as measured by height and diameter, and reduced the needle dry mass and net photosynthetic rate of $F_1$, but had almost no effect on the Dahurian larch or Japanese larch. There was a significant increase in whole-plant dry mass induced by elevated [$CO_2$] in $F_1$ but not in the other two species. Photosynthetic acclimation to elevated [$CO_2$] was observed in all species. The net photosynthetic rate measured at the growing [$CO_2$] (i.e. 380 ppm for ambient treatment and 600 ppm for elevated $CO_2$ treatment) was nevertheless greater in the seedlings of all species grown at elevated [$CO_2$]. The high [$CO_2$] partly compensated for the reduction of stem diameter growth of $F_1$ at high [$O_3$]; no similar trend was found in the other growth and photosynthetic parameters, or in the other species.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.60-66
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• 1995

The treatability of Japanese larch heartwood was assessed by pressure treatment of non-incised dimension material with CCA or CCFZ. The effectiveness of incising(conventional, high density, and needle incising) for improving CCA treatability on refractory Japanese larch heartwood was also investigated. Preservative retention and penetration were somewhat greater with CCFZ treatment, although those was generally poor in both preservatives. The retention gradients for both CCA and CCFZ-treated stock were essentially the same shape. Treatment of non-incised material with CCA acheived the recommended treatability for using treated wood at the regions of hazard class H2 in the Japanese Agricultural Standards. However, Japanese larch heartwood would require incising as a pretreatment for enhancing treatability, if CCA-treated larch is intended to be used at the regions of hazard class H3 and H4. As expected, incising resulted in a considerable improvement of preservative treatability, particularly penetration, and the effect of incising on the improvement of treatability was excellent at the sequence of needle incising, high density incising, and conventional incising. Among incising techniques investigated in this study, high density and needle incising enhanced CCA treatability beyond the point where it did meet a minimum requirements specified by the Japanese Agricultural Standards for using CCA-treated Japanese larch at the regions of hazard class H3 and even H4.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.258-268
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• 2011

This study was conducted to investigate the effects of sawdust size and moisture content, pelletizing temperature and time on the durability of the pellets fabricated with larch and tulip tree sawdust. The durability of larch-pellet was significantly higher than that of tulip tree-pellet. For the larch-pellets, the durability of the pellets fabricated with > 18 mesh sawdust was higher than that of 8~18 mesh sawdust. With the increases of pelletizing temperature and time, the durabilities of larch- and tulip tree-pellets steadily improved. The durabilities of larch- and tulip tree-pellets also increased as the moisture content of sawdust increased. In the comparison of durabilities between commercial pellets and larch- or tulip tree-pellets, the pellets fabricated with larch and tulip tree sawdusts in our study were less denser than commercial pellets, but the durability of most larch-pellets was satisfied with the 1st-grade pellet standard designated by Korea Forest Research Institute. In addition, the durability of tulip tree-pellets were higher than that of the 3rd-grade pellet standard. From the scanning electron microscopic observation of larchand tulip tree-pellets, the gap between the sawdusts of each pellet was reduced with the increases of pelletizing temperature and time. In particular, it was visually confirmed that the surface of the pellets made with the pelletizing temperature of $180^{\circ}C$ for 3 min did not differ from that of commercial pellets.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.97-102
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• 2009

This study was carried out to evaluate litterfall dynamics in three adjacent coniferous tree plantations (larch: Larix leptolepis; red pine: Pinus densiflora; rigitaeda pine: P. rigitaeda) planted in the same year (1963), and growing under similar environmental conditions in the Sambong Exhibition Forests, Hamyang-gun, Gyeongsangnam-do. Litter was collected monthly between July 2006 and June 2008. Needle, broad leaf and total litter inputs followed a similar monthly pattern in the three coniferous plantations. The amounts of needles, flowers, and miscellaneous litter were significantly lower in the larch than in the two pine plantations, while branch litter was significantly higher in the larch than in the two pine plantations. Average total litterfall for two years was significantly higher for the pine (5,475 kg $ha^{-1}\;yr^{-1}$ for red pine and 5,290 kg $ha^{-1}\;yr^{-1}$ for rigitaeda pine) plantations than for the larch (3,953 kg $ha^{-1}\;yr^{-1}$ plantation. Needle litter comprised about 73.1% of total litterfall for the rigitaeda pine, 70.8% for the red pine and 62.9% for the larch plantations. Our results demonstrate that litterfall inputs can be affected by tree species.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.720-725
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• 2010

On the basis of vegetation data in the 9.12 ha (380 m ${\times}$ 240 m) permanent sample plot of the spruce-fir valley forest in Liangshui National Reserve of Xiaoxing'an Mountains, the study was conducted to evaluate spatial distribution pattern and spatial association by using point pattern analysis for living and dead trees of Larix gmelini by DBH size class. The number of L. gmelini were counted as 59 living stems/ha (6.42 $m^2$/ha of basal area) and 34 dead stems/ha (2.86 $m^2$/ha of basal area). The distributional curve of diameter class exhibited bimodal shape. The analysis of spatial distribution patterns of all living larch stems noted the clumped distribution on the whole. The size of larch aggregates of dead stems was decreased as diameter class was increased. The distribution of dead stems became gradually randomized with decreased clumped size as the scale increased. Living stems and dead stems of the larch had positive spatial association at most of scales, illustrating that the occurrence of mortality of the larch tree was closely related to the distribution pattern of living larch trees.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.99-106
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• 2016

Our aim was to identify the potential of reed stalk as a raw materials for biomass pellet production. Compared to woody biomass, reed stalk contained significant levels of ash. The holocellulose content of reed stalk was similar to that of larch, but the lignin content of reed stalk was lower than that of larch. In the elemental analysis, chlorine content of reed stalk was much higher than that of larch, and satisfied only the mixed biomass pellet B of European non-woody pellet standards(EN 14961-6). In quantitative analysis of the ash, heavy metals contents of reed stalk satisfied European non-woody pellet standards. Higher heating value of oven-dried reed stalk pellet was slightly lower than that of larch wood pellet. The durability of reed stalk pellet was lower than that of larch wood pellet. The results of this study indicate that reed stalk might be used as a raw material of mixed biomass pellet B.