• Journal of Energy Engineering
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• v.24 no.2
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• pp.120-128
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• 2015

This study reports the combustion characteristics, such as burner temperature and the concentration of exhausted gas ($O_2$, $CO_x$, $NO_x$) due to the different types and pitches of the fuel supply feeder of the wood pellet boiler. The 1st grade wood pellets composed of mainly larch have been used for the experiment. In case of using the spring feeder, mean temperature of burner was approximately $821.76^{\circ}C$, and the mean concentration of oxygen, carbon monoxide, carbon dioxide and nitrogen oxide were approximately 8.88%, 93.35ppm, 12.15% and 139.83 ppm, respectively. The test result with the spring feeder was shown to approach the condition of complete combustion compared to that of a screw feeder and were in good agreement with authentication judgement standard. Furthermore, the combustion efficiency was improved according to the growth of screw pitch. The control of air flow rate from the blower and ventilator is needed to achieve the complete combustion.

• Journal of Plant Biotechnology
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• v.40 no.3
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• pp.141-146
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• 2013

This study was conducted to examine suspended embryogenic cells growth with days of culture, effects of various kinds/concentrations of osmoticum for induction of somatic embryos (SEs), following somatic embryos germination or plantlet regeneration. The proliferation pattern of embryogenic cells in suspension culture is characterized by settled cells volume (SCV) increased with the duration of culture with marked the maxium of SCV (10.1 ml) in 18 days of culture, however the SCV of cells gradually decreased after that. In comparison of kinds/concentrations of osmoticum on somatic embryo induction, the highest induction number (352.3/g FW) of the SE was showed in 0.2 M sucrose, in addition, we also observed some effects with treatments of 0.2 M maltose (203.7) and 0.3 M maltose (193.7), respectively. However, no somatic embryos produced in treatments of 7.5% PEG plus 0.15 M sucrose or maltose. In comparison of germination efficiency of SEs which occurred from the treatments of various kinds/ concentrations of osmoticum, the highest induction frequency of cotyledon (25.2%) was obtained from SEs that produced 0.3 M maltose, however, the best occurrence rates of hypocotyl (39%), radicle (30.3%) and plantlet regeneration (3.5%) were observed from the 0.2 M sucrose treatment, respectively.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.42-48
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• 1995

With the aim to investigation of decay resistance and optimum concentration in chrome-copper-arsenic(CCA) preservative treatment on the imported softwoods from Siberia and North america, preservative absorption after CCA impregnation, weight losses and degradation patterns by decay fungi were examined. The density and latewood rate of Siberia softwoods(Spruce and Larch) were higher than those of North america softwoods(Douglas-fir and Western hemlock), resulting in the decrease of the CCA preservative absorption in the Siberia softwoods. In the case of untreated softwoods, decay resistance against Coriolus versicolor was lower than against Tyromyces palustris. For CCA treated softwoods, preservative effectiveness increased with increase in concentration of CCA solution. When treated with 0.7% CCA solution, efficiency value was more than 80 and 90 for C. versicolor and T. palustris, respectively. From this results, in the CCA preservative treatment for imported softwoods, it can be concluded that optimum concentration of CCA solution is approximately 0.7%. The absorption of CCA preservative distributed in the range of 3.8 and $5.5kg/m^3$. After exposure to testing fungi, in the untreated softwoods, bore holes formed in the cell walls and bordered pits, moreover, bordered pit canals enlarged by the fungi. However, 0.5% CCA treated softwoods was almost no deterioration in the cell walls and bordered pits due to decay.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.77-84
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• 2016

Seedling stage is particularly important for tree survival and is easily influenced by warming. Therefore, air temperature being increased due to climate change may affect physiological traits and growth of seedlings. This study was conducted to investigate the physiological and growth responses of Larix kaempferi seedlings to open-field experimental warming. 1-year-old and 2-year-old L. kaempferi seedlings were warmed with infrared lamps since April 2015 and April 2014, respectively. The seedlings in the warmed plots were warmed to maintain the air temperature to be $3^{\circ}C$ higher than that of the control plots. Physiological responses (stomatal conductance, transpiration rate, net photosynthetic rate and total chlorophyll content) and growth responses (root collar diameter (RCD), height and biomass) to experimental warming were measured. Physiological and growth responses varied with the seedling ages. For 2-year-old L. kaempferi seedlings, stomatal conductance, transpiration rate and net photosynthetic rate decreased following the warming treatment, whereas there were no changes for 1-year-old L. kaempferi seedlings. Meanwhile, total chlorophyll content was higher in warmed plots regardless of the seedling ages. Net photosynthetic rate linked with stomatal conductance also decreased due to the drought stress and decrease of photosynthetic efficiency. In response to warming, RCD, height and biomass did not show significant differences between the treatments. It seems that the growth responses were not affected as much as physiological responses were, since the physiological responses were not consistent, nor the warming treatment period was enough to have significant results. In addition, multifactorial experiments considering the impact of decreased soil moisture resulting from elevated temperatures is needed to explicate the impacts of a wide range of possible climate change scenarios.

• Journal of Mushroom
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• v.17 no.3
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• pp.126-131
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• 2019

This study sought to identify the optimum substrate composition for the stable bottle cultivation of Sparassis latifolia. The main substrate was fermented larch sawdust. Six nutrient sources were mixed at a maximum volume ratio of 20%. The fresh weight of fruit body was the highest at 128.5 g for GMSL69033 and 126.6 g for 'Neoul' in the treatments of beet pulp and corn flour in a volume ratio of 15:5. In addition, the total cultivation period was 94 days, which was shorter than that required for other treatments. The selected substrate characteristics were pH 4.7, C:N (carbon to nitrogen) ratio of 106:4, moisture content of 70%, and air filling porosity of 38%. We plan to develop new income items through research on mycelial incubation and fruit body growth conditions.

• Journal of the Korean Wood Science and Technology
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• v.7 no.2
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• pp.3-30
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• 1979

Larch ($\underline{Larix}$ $\underline{leptolepis}$ GORDON), one of the major afforestation species in Korea in view of its growing stock and rate of growth, is not favored as a raw material for pulp due to its low yield of pulp and difficulties with bleaching arising from the high content of extractives in wood, and the high heartwood ratio and the active phenolics, respectively. The purpose of this study is to investigate the characteristics of firstly pulping with various additives of cellulose protector for the yield of pulp, and secondly bleaching with oxygen for chlotination-alkali extraction of five stage-sequence to reduce chlorine compounds in bleaching effluents. The kraft cooking liquor for five age groups of larchwood was 18 percent active alkali with 25 percent sulfidity and 5 : 1 liquor-to-wood ratio, and each soda liquor for sap-and heart-wood of the 15-year-old larchwood was 18 percent alkali having one of the following cellulose protectors as the additive; magnesium sulfate ($MgSO_4$, 2.5%), zinc sulfate ($ZnSO_4$, 2.5%), aluminium sulfate ($Al_2(SO_4)_3$, 2.5%), potasium iodide (KI, 2.5%), hydroquinone (HQ, 2.5%), anthraquinone (AQ, 0.1%) and ethylene diamine (EDA, 2.5%). Then each anthraquinone-soda liquor for the determination of suitable cooking condition was the active alkali level of 15, 17 and 19 percent with 1.0, 0.5 and 0.1 percent anthraquinone, respectively. The cooking procedure for the pulps was scheduled to heat to 170$^{\circ}C$ in 90 minutes and to cook 90 minutes at the maximum temperature. The anthraquinone-soda pulps from both heartwood and sapwood of 15-year-old larchwood prepared with 0.5 percent anthraquinone and 18 percent active alkali were bleached in a four-stage sequency of OCED. (O: oxygen bleaching, D: chlorine dioxide bleaching and E: alkali extraction). In the first stage oxygen in atmospheric pressure was applied to a 30 percent consistency of pulp with 0.1 percent magnesium oxide (MgO) and 3, 6, and 9 percent sodium hydroxide on oven dry base, and the bleached results were compared pulps bleached under the conventional CEDED (C: chlorination). The results in the study were summarized as follows: 1. The screened yield of larch kraft pulp did not differ from particular ages to age group, but heartwood ratio, basic density, fiber length and water-extractives contents of wood and the tear factor of the pulp increased with increasing the tree age. The total yield of the pulp decreased. 2. The yield of soda pulp with various chemicals for cellulose protection of the 15-year-old larchwood increased slightly more than that of pure soda pulp and was slightly lower than that of kraft pulp. The influence of cellulose protectors was similar to the yield of pulps from both sapwood and heartwood. The effective protectors among seven additives were KI, $MgSO_4$ and AQ, for which the yields of screened pulp was as high as that of kraft pulp. Considering the additive level of protector, the AQ was the most effective in improving the yield and the quality of pulp. 3. When the amount of AQ increased in soda cooking, the yield and the quality of the pulp increased but rejects in total yield increased with decreasing the amount of active alkali from 19 to 15 percent. The best proportion of the AQ seemed to be 0.5 percent at 17 percent active alkali in anthraquinone-soda pulping. 4. On the bleaching of the AQ-soda pulp at 30 percent consistency with oxygen of atomospheric pressure in the first stage of the ODED sequence, the more caustic soda added, the brighter bleached pulp was obtained, but more lignin-selective bleaching reagent in proportion to the oxygen was necessary to maintain the increased yield with the addition of anthraquinone. 5. In conclusion, the suitable pulping condition for larchwood to improve the yield and quality of the chemical pulp to the level for kraft pulp from conventional process seemed to be. A) the selection of young larchwood to prevent decreasing in yield and quality due to the accumulation extractives in old wood, B) the application of 0.5 percent anthraquinone to the conventional soda cooking of 18 percent active alkali, and followed, C) the bleaching of oxygen in atmospheric pressure on high consistency (30%) with 0.1 percent magnesium oxide in the first stage of the ODED sequence to reduce the content of chlorine compounds in effluent.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.541-554
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• 1999

The objectives of this study were to examine the amount of nutrient input by throughfall and stemflow, and the nutrient dynamics by throughfall, stemflow and soil solution among Piuns koraiensis, Larix leptolepis and hardwood forests including oaks at Kwangju-Gun, Kyonggi-Do. A total amount of rainfall during the study period was 1410.1mm. Of the total rainfall, 85% was from throughfall at the L. leptolepis stand, 84.5% at the thinned P. koraiensis stand, 83.2% at the unthinned P. koraiensu stand and 81.2% at the hardwood stand, showing greater throughfall at the conifer stand than at the hardwood stand. Stemflow showed 2.7% of rainfall at the hardwood stand, 1.3% at the unthinned P. koraiensis stand, 1.2% at the thinned P. koraiensis stand and 0.8% at the L. leptolepis stand, showing greater stemflow at the hardwood stand than at the conifer stand. Ion concentration of stemflow was greater than those of rainfall and throughfall. The conifer stand showed higher ion concentration than the hardwood stand both for cation and anion. The ion concentrations of throughfall and stemflow were higher in the descending order : $NH{_4}^+$-N > $K^+$ > $K^+$ > $Na^+$ > $Mg^{2+}$ for cations and $SO{_4}^{2-}$ > $NO{_3}^-$-N > $Cl^-$-N for anions. After the precipitation passed through the canopy, $K^+$ increased most at the hardwood stand, whereas $NH{_4}^+$-N did most at the P. koraiensis and L. leptolepis stands. The ion concentration of soil solution was higher in the descending order : $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ for cations and $NO{_3}^-$-N > $Cl^-$ > $SO{_4}^{2-}$ for anions. $NH{_4}^+$-N and $K^+$ seemed to be supplied primarily from atmospheric deposition while $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ from weathering.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.58-68
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• 2015

This study compares the wind stability of Larix kaempferi (Lamb.) Carr., Pinus koraiensis Sie. & Zucc. and Abies holophylla Maxim. to understand and inform wind risk management of these plantation trees at Daegwallyeong, Korea. Temporary square plots of $20m{\times}20m$ ($400m^2$) were laid out, and DBH (Diameter at Breast Height) and height for trees greater than 10 cm in DBH were measured by species. A total of 15 plots with 5 plots each in L. kaempferi, P. koraiensis and A. holophylla stands were sampled at random. Among the species, A. holophylla and P. koraiensis have comparatively lower h/d (Height/DBH) ratios than L. kaempferi. These results indicate that the former two species are more wind firm than the latter species. About 9% of the L. kaempferi trees have higher h/d ratios than the critical threshold limit 80. These trees are vulnerable to wind damage and should be removed in the next thinning regime. The analysis of variance detected a significant difference (p < 0.05) in the h/d ratios and Gini coefficient indicating species differences and DBH size variation, respectively. Gini coefficient was 16.4% in A. holophylla, 15.9% in P. koraiensis and 14% in L. kaempferi stands indicating limited DBH size variation. Lower h/d ratios are attributed to thinning in these stands and tree morphological differences. To increase wind firmness, low thinning should concentrate to remove trees with the h/d ratio above 80 coinciding at the time of stand distinction phase. Forest managers and practitioners should measure and maintain h/d ratios of trees below the critical threshold limit of 80 through stand density management. Variable density thinning approach should be tested to increase tree DBH sizes of the even-aged stands.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.19-25
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• 2004

This study was carried out to investigate a radial distribution of moisture contents (MCs) within a log cross section (LC) during oven-drying of 3 mm-thick circumferential slices cut from several domestic softwoods LCs.For Korean red pine, drying rate of sapwood slices during oven-drying represented much higher values than that of heartwood slices, and so sapwood with higher green MC early reached below fiber saturation point (FSP) rather than heartwood did. However, this distribution of moistures did not last for long duration. For Japanese larch, green MC of sapwood was approximately three times higher than that of heartwood. This similar distribution in MC was lasted until about 20% average MC. The MC was around uniform throughout the sapwood of Ginkgo when green and during oven-drying, although it was somewhat fluctuated. For Japanese cedar, the heartwood with so low moistures around FSP would begin to shrink from the beginning stage of drying, but the sapwood above hygroscopic MC prevents the heartwood from shrinking, and consequently, the heartwood or the transition wood goes into tension stress. The results for Japanese cypress showed that the green MCs of the sapwoods were much lower than those for heartwoods, and then this trend was continued until about 20% in average MC. For Chinese thuja, the green MCs of sapwoods were about 2 times as high as those of heartwood, but this along the radial gradient in MC rapidly became gentle during oven-drying.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.578-586
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• 2013

This study was performed in Pinus rigida and Larix kaempferi plantations which occupy approximately 60% of artificial forest area in Korea. The objective of this study was to know the differences in soil physical and chemical properties between both plantations. Soil physical and chemical properties from published literature and analyzed soil data in national forest in 2010 and 2011 were analyzed by plantation regions and stand age of 5 years unit. Jeollanamdo in Pinus rigida plantations and Gyeongsangbuk-do in Larix kaempferi plantations showed higher soil chemical properties than those of other regions. Soil texture in both plantations was almost loam and sandy loam. Mean soil pH in Pinus rigida and Larix kaempferi plantations were 4.86 and 4.87, respectively and there was no relationship between soil pH and stand age. The mean concentrations of total nitrogen (%) and available phosphorus (mg $kg^{-1}$) were 0.21 and 11.00 for Pinus rigida plantation and 0.28 and 13.32 for Larix kaempferi plantation. In Larix kaempferi plantation, total nitrogen, available phosphorus and organic matter concentrations and C.E.C. were higher than those in Pinus rigida plantation and showed positive relationship with stand age. This positive relationship was also revealed between the exchangeable cations and soil pH. The results of this study provide an informative data in selecting tree species for planting and contribute to the establishing forest management plan for the maintenance of sustainable forests resources.