• Journal of the Korean Wood Science and Technology
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• v.44 no.4
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• pp.607-615
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• 2016

The delamination along the annual ring on the cross-section of laminae and the bonding strength according to the tangential angle between laminae were evaluated for the production of 3-ply cross-laminated timber (CLT) using domestic larch. Since there is no standard for CLT in Korea, the production and test of specimens for bonding strength followed the standard procedure of "Structural glued laminated timber" (KS F 3021). The standard specifies to exclude any measurement from the cracks of timbers resulted from drying or knots during delamination test of the glued laminated timbers. However, the failure of cross-sectional tissues along the annual rings was observed near the glue-line of all specimens during the delamination test. Because this phenomenon can generate defects in the CLT that may be exposed to various temperatures and relative humidities after the actual construction, the delamination percentage was measured by including this wood failure. As a result, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed inward was the lowest, which was around 13%, regardless of the annual ring direction of the middle lamina. On the other hand, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed outward was the highest, which was around 26%. Furthermore, end-split occurred in the outer lamina during the drying process of the boiling delamination test, which affected the delamination percentage. Therefore, the soaking delamination test was found to be more appropriate for evaluating the delamination strength of CLT. The block shear strength of larch CLT was $3.9{\pm}0.9$ MPa on average, which was 46% lower than the block shear strength requirement (7.1 MPa) of the standard, but satisfied the criteria of the block shear strength (3.5 MPa) of the European Standard (prEN 16351: 2013).

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.202-212
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• 2017

This study was to establish the interrelation between chemical compositions and near infrared (NIR) spectra for the classification on distinguishability of domestic gymnosperms. Traditional wet chemistry methods and infrared spectral analyses were performed. In chemical compositions of five softwood species including larch (Larix kaempferi), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), cypress (Chamaecyparis obtusa), and cedar (Cryptomeria japonica), their extractives and lignin contents provided the major information for distinction between the wood species. However, depending on the production region and purchasing time of woods, chemical compositions were different even though in same species. Especially, red pine harvested from Naju showed the highest extractive content about 16.3%, whereas that from Donghae showed about 5.0%. These results were expected due to different environmental conditions such as sunshine amount, nutrients and moisture contents, and these phenomena were also observed in other species. As a result of the principal component analysis (PCA) using NIR between five species (total 19 samples), the samples were divided into three groups in the score plot based on principal component (PC) 1 and principal component (PC) 2; group 1) red pine and Korean pine, group 2) larch, and group 3) cypress and cedar. Based on the chemical composition results, it was concluded that extractive content was highly relevant to wood classification by NIR analysis.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.1032-1046
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• 2016

The purpose of this study was to provide basic information on ecological forest management in Janggunbong, Bonghwa-Gun. Vegetation data were collected from Janggunbong, Bonghwa-Gun, from July, 2014 to October, 2015. We carried out an analysis of vegetation types on the physiognomically dominant species of 111 quadrates. In the natural forest area, the vegetation community was classified into Quercus mongolica, Betula schmidtii, Pinus densiflora, Quercus variabilis and Tilia amurensis. In the plantation area, the vegetation community was classified into Pinus koraiensis, Larix kaempferi, Fraxinus rhynchophylla and Betula platyphylla var. japonica. Based on the analysis of the importance value of the species in the slope area, it was seen that the tree layers of the natural forest were dominated by Quercus mongolica at 44.3, and Pinus densiflora at 12.1. The importance values of the subtree layer of the natural forest were found to be 27.6 for Quercus mongolica, and 12.4 for Fraxinus sieboldiana. Also, the importance values of the tree layers in the plantation areas were found to be 22.6 for Pinus koraiensis, 15.4 for Larix kaempferi, and 13.3 for Fraxinus rhynchophylla, while those of the subtree layers of the plantation area were found to be17.9 for Quercus variabilis, 14.1 for Parthenocissus tricuspidata, and 10.4 for Quercus mongolica in that order. Vine plants showed higher importance values in the plantation area than in the natural forest area. Species diversity in the valley area was 2.334 in the natural forest area, and 1.734 in the plantation area. That of natural forest area was 1.931, and that of plantation area was 1.927 in slope area. For management of the forest vegetation in Mt. Janggunbong, a distinct forest management plan, customized for each topography and physiognomical community unit should be made Particularly, the administration is required to consider strategies to reduce the higher importance value for vine plants in the plantation areas.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.16-25
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• 2009

Cauliflower mushroom (Sparassis crispa) is recently recognized as a new edible and/or medicinal mushroom cultivated with conifers. By the way, the mushroom is notorious as a brown-rot fungus that causes a buttrot of larch. So, there should be a careful consideration to apply the mushroom cultivation in coniferous stand. This study was conducted to clarify the seriousness of heartwood decay on conifers such as larch by cauliflower mushroom with surveying the mushroom producing environment and to examine whether the cultivation of cauliflower mushroom produce any problem in conifer stands or not. The mushroom occurred in various coniferous stands such as Larix kaempferi, Pinus koraiensis, P. densiflora and Abies holophylla on fertile soils with adequate moisture. Soil texture of the mushroom producing site was comparatively fine compared to general forest soils; sandy loam, loam and silty loam. Soil pH ranged from 4.6 to 5.2, and organic matter contents were 4~11%, which showed relatively wide range. We could find S. crispa by a DNA technique from the wood that seemed to have no heartwood decay by naked eyes. The damaged wood showed 30% higher moisture contents than that of sound wood, while the compressive strength was 30% lowered down compared to that of sound wood. The fungus may invade conifers through the scars occurred on roots or stems, in this case spore dispersion of the mushroom takes a great role. Thus, we concluded that forest tending activities need to be applied with considering the invasion of S. crispa, and cultivation of cauliflower mushroom in forest should be attempted very carefully. By the way, we also infer that conifer stands can be nurtured without heartwood decay by S. crispa if the stand be managed in good aeration conditions by proper silvicultural practices such as sanitary thinning.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.648-657
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• 2021

This study was conducted to estimate the volume growth by forest type and major species using the national forest resource inventory and to predict the final age of maturity by deriving the mean annual increment (MAI) and the current annual increment (CAI). We estimated the volume growth using the Chapman-Richards model. In the volume estimation equations by forest type, coniferous forests exhibited the highest growth. According to the estimation formula for each major species, Larix kaempferi will grow the highest among coniferous tree species and Quercus mongolica among broad-leaved tree species. And these estimation formulas showed that the fitness index was generally low, such as 0.32 for L. kaempferi and 0.21 for Quercus variabilis. In the analysis of residual amount, which indicates the applicability of the volume estimation formula, the estimates of the estimation formula tended to be underestimated in about 30 years or more, but most of the residuals were evenly distributed around zero. Therefore, these estimation formulas have no difficulty estimating the volume of actual forest species in Korea. The maximum age attained by calculating MAI was 34 years for P. densiflora, 35 years for L. kaempferi, and 31 years for P. rigida among coniferous tree species. In broad-leaved tree species, we discovered that the maximum age was 32 years for Q. variabilis, 30 years for Q. acutissima, and 29 years for Q. mongolica. We calculated MAI and CAI to detect the point at which these two curves intersected. This point was defined by the maximum volume harvesting age. These results revealed no significant difference between the current standard cutting age in public and private forests recommended by the Korea Forest Service, supporting the reliability of forestry policy data.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.71-82
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• 2023

Forest biomass is used as a representative indicator of forest size, maturity, and productivity. Therefore, quantitative evaluation is important for management and harvest as well as the evaluation of ecosystem functions and services including CO₂ absorption. The allometric equation is a widely used method for estimating the value of each component through the relative growth rate of plants. Recently, studies indicated that the relative growth of trees is changing because of the increased CO₂ concentration in the atmosphere and the resulting climate change, raising the need to review the previously developed relative growth models and coefficients. In this study, the height-diameter at breast height (DBH) relationships of four major tree species in Korea [(Pinus densiflora (PD), Larix kaempferi (LK), Quercus variabilis (QV), and Quercus mongolica (QM)] were analyzed using the 5th-7th National Forest Inventory (NFI) data. Furthermore, these results were compared with the present yield table from the National Institute for Forest Science. This analysis revealed that the expected height for the same DBH increased as the NFI progressed. For example, in model analysis, the expected heights for PD, LK, QV, and QM for DBH of 25 cm were 12.48, 19.17, 14.47, and 13.19 m, respectively, in the 5th NFI data. In the 7th NFI data, these values were estimated as 13.61 (+9.1%), 21.58 (+12.7%), 15.76 (+8.9%), and 13.93 m (+5.6%), respectively. These results indicate that the major tree species in South Korean forests currently are more vigorous in height growth than in diameter growth when compared to the height-DBH development trends by tree species identified through past survey data.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.72-79
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• 2014

Adventitious buds were produced from the cultures of mature zygotic embryos of Larix kaempferi with the highest frequency in Quoirin & Lepoivre (LP) medium containing 1.0 mg/L zeatin (76.1%). The effective treatments for inducing adventitious shoots growth above 2 mm were shown in Litvay (LM) medium with 0.5 mg/L zeatin (75.2%) or LP medium with 2.0 mg/L zeatin (70.2%), respectively. In experiment with half strength salts medium for induction of the adventitious buds, the effective treatments were obtained from 1/2LP medium with 1.0 (83.3%) or 2.0 mg/L (81.7%) zeatin, respectively. However, the best adventitious shoot growth more than 2 mm appeared in 1/2LM medium with 1.0 mg/L zeatin (66.7%). In experiment with half strength salts medium for induction of the adventitious buds, the effective treatments were obtained from 1/2LP medium with 1.0 (83.3%) or 2.0 mg/L (81.7%) zeatin, respectively. However, the best adventitious shoot growth more than 2 mm appeared in 1/2LM medium with 1.0 mg/L zeatin (66.7%). In experiment of subsequent treatment with various cytokinins for induction of the adventitious buds, the best one (52.9%) was obtained from 1.0 mg/L zeatin for 2weeks, and then subcultured to the medium with 1.0 mg/L thidiazuron (TDZ). The effect of ethylene synergist or inhibitor on adventitious buds induction was examined. The highest rate (34.6%) of adventitious buds marked from the treatments of 1.0 mg/L zeatin+2.0 mg/L MGBG (methylglyoxal bis-[guanylhydrazone]). And the highest no. of adventitious buds(1.5/explant) was shown in the medium with 1.0 mg/L zeatin+2.0 mg/L $CoCl_2$.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.4
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• pp.41-54
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• 2011

Tree roots can enhance soil shear strength and slope stability. However, there has been a limited study about root reinforcement of major tree species in Korea because of some experimental difficulties. Thus, this study was conducted to analyze the performance of Japanese larch (Larix kaempferi) and Korean pine (Pinus koraiensis) which are two common plantation species in Korea. Profile wall method was used to measure the spatial distribution of root system and its diameter within 15 soil walls of Japanese larch stand and 13 soil walls of Korean pine stand in Taehwa University Forest, Seoul National University, Korea. Root tensile properties of each species were assessed in the laboratory, and root reinforcements were estimated by Wu model. The study observed that the number and cross-sectional area (CSA) of root in both species could tend to decrease with soil depth. Especially, CSA were well-fitted to exponential functions of soil depth. Mean root area ratios (RAR) were 0.03% and 0.10% for Japanese larch and Korean pine, respectively. Estimated root reinforcement from Wu model were, on the average, 4.04 kPa for Japanese larch and 12.26 kPa for Korean pine. Overall, it was concluded that root reinforcement increased the factor of safety (Fs) of slope for small-scale landslide as the result of two-dimensional (2-D) infinite slope stability analysis considering vegetation effects.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.236-242
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• 2013

It is known not only that antifungal compounds such as sparassol, methyl orsellinate (ScI) and methyl-dihydroxy-methoxy-methylbenzoate (ScII) were produced during submerged culture from Sparassis crispa, but also that ScI and ScII were appeared higher antifungal activity than sparassol. The aim of this study, antifungal compounds of Sparassis latifolia were purified from mycelial culture media and identified by using NMR and ESI-MS. Based on HPLC analysis, methyl orsellinate and sparassol were detected at 15 min and 31 min of retention time, respectively. The compounds derived from S. latifolia were classified into four production patterns according to their strains. The strains originated from host plant Larix kaempferi and Pinus koraiensis showed different patterns of compound production, whereas the strains originated from host plant P. densiflora and Abies holophylla showed almost same patterns. There was no correlation between mycelial biomass and compound production. KFRI 645 strain from L. kaempferi exhibited higher methyl orsellinate production (0.170 mg/ml). Sparassol was produced by KFRI 747 from P. densiflora (0.004 mg/ml). Thus, our result revealed the new fact that methyl orsellinate and sparassol have different patterns according to the strains originated from different host plants.

• Journal of Climate Change Research
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• v.4 no.2
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• pp.177-188
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• 2013

In this research, forest cover distribution change, forest volume and carbon stock in Yongin-city, Gyeonggi procince were estimated focused on the forest of Yongin-City using forest type map and HyTAG model in relation to climate change. Present forest volume of Yongin-city was estimated using the data from $5^{th}$ Forest Type Map and Korean National Forest Inventory (NFI). And for the future 100 years potential forest distribution by 10-year interval were estimated using HyTAG model. Forest volume was also calculated using algebraic differences form of the growth model. According to the $5^{th}$ Forest Type Map, present needleleaf forest occupied 37.8% and broadleaf forest 62.2% of forest area. And the forest cover distribution after 30 years would be changed to 0.13% of needleleaf forest and 99.97% of broadleaf forest. Finally, 60 years later, whole forest of Yongin-city would be covered by broad-leaf forest. Also the current forest carbon stocks was measured 1,773,862 tC(56.79 tC/ha) and future carbon stocks after 50 years was predicted to 4,432,351 tC(141.90 tC/ha) by HyTAG model. The carbon stocks after 100 years later was 6,884,063 tC (220.40 tC/ha). According to the HyTAG model prediction, Pinus koraiensis, Larix kaempferi, Pinus rigida, and Pinus densiflora are not suitable to the future climate of 10-year, 30-year, 30-year, and 50-year later respectively. All Quercus spp. was predicted to be suitable to the future climate.