• Korean Journal of Plant Resources
• /
• v.14 no.1
• /
• pp.53-59
• /
• 2001

This study was carried out to investigate mass propagation technique by using seed and vegetative propagation of Kalopanax pictus Nakai. For developing seed propagation, seed stratification and 1$0^{\circ}C$ after-ripening treatment induced embryo growth within 1 weeks, resulted in increasing germination rate of seeds up to more than 65% when planted. The softwood cutting using one year old shoot increased rooting rate to 69% whereas more than 1 year old shoot looked like inappropriate for cutting propagation. In the cutting timing, the rooting rate on June, 13 cutting of the first growth shoot was the highest, followed by June 20 and July 4. The most efficient cutting timing seemed to be the middle of June. When cutted shoots were soaked for 30 minute with IBA and NAA 1000mg.$L^{-1}$, rooting rate was increased above 70%. As the concentrations of plant hormone were increased above 2000mg.$L^{-1}$, the rooting rate was slowly decreased.

• Journal of Korean Society of Forest Science
• /
• v.89 no.1
• /
• pp.1-8
• /
• 2000

This paper investigates the empirical validity of market integration for the five softwood lumber markets in Canada : Atlantic, Quebec, Ontario, Prairie, and British Columbia (BC). The Augmented Dickey-Fuller (ADF) tests of monthly price series for the period 1987 : 10-1998 : 11 reveal strong evidence for the presence of a unit root in each series. Accordingly, the Johansen cointegration technique is used to test for the law of one price in the five regional markets. Results show that the law holds in the pair, three, four, and five markets, supporting the hypothesis of market integration.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.3
• /
• pp.14-24
• /
• 2000

In present research, the plywoods made of radiata pine or Japanese larch, the potential softwood species in mass supply, were discussed to examine their feasibility as the structural and concrete form panels through the basic properties test. First, plywood qualities and its nail performance were tested. The performance test for concrete form or structural panel by concentrated and uniformly distributed load were conducted to investigate the possibility as structural material for light frame and concrete constructions. Test results of basic quality such as specific gravity, cupping, bowing, and twisting appeared to satisfy the criteria for structural use. Also, nail performance test results, for roof and wall sheathing panels, nail lateral resistance, nail withdrawal resistance, and nail push head resistance proved to meet the required standard for structural use. The test results on performance as structural panel by concentrated and uniformly distributed load and as concrete form panel showed that these two species could be used for structural sheathing, subfloor, and concrete form panels.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.1
• /
• pp.25-35
• /
• 2015

The goal of this study was to review the visual grading and allowable stress determination methodologies for the domestic softwood. Previous studies used different grading (KFRI 1995-27, KFRI 2000-39, KFRI 2007-3, KFRI 2009-1) and allowable stress determination methodologies (ASTM D 245, KS F 2152, JAS 1990). The results of the visual grading were different by each researcher. Compared to the $1^{st}$ grade proportion from the previous studies using the previous specification on visual grading (KFRI 1995-2007), a higher $1^{st}$ grade proportion was found from the studies using the current specification (KFRI 2009). Compared to the allowable stress values from the small clear sample, the higher allowable stress values from the structural size were found. The results indicated that the strength reduction factor used in small clear sample was too conservative for the different grades. To obtain consistent results for the grade, it is required to have experts in visual grading and authorized organizations. An official standard methodology for the allowable stress value determination needs to be defined for the reliable stress value.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.32 no.2
• /
• pp.120-129
• /
• 2004

This study was carried out to develop new varieties with early maturing and large fruit size in the Korean native dogwood (Cornus kousa) for woody landscape plants from native sites or cultivated area. The results are obtained as follows; We selected strains with early maturing and large fruit. size from the habitats from 2000 to 2003. ‘SKK 2-1’ had 4.0cm of fruit size while 2.0 cm of native variety. In addition, ‘SKK 2-2’, ‘SKK 2-3’, ‘SKK 2-4’, and ‘SKK 2-5’ with large fruit and early maturing were preliminary selected from the habitats. In the preliminary selections, ‘SKK 2-1’ was finally selected as new early maturing variety with large fruits in 2003. New early maturing variety with large fruit size, C. kousa var. ‘SKK 2-1’ was selected from 200 plants of 5-year-old seedlings in C. kousa in 5-12 Nung wean ri Goo sung myun Yong In, Kyung gi do, Korea in 2000. Their fruits were colorized in September 18, 20∼25 days earlier than October 7 of native varieties. Its fruit diameter is larger than 4cm. Its fruit weight was 5 times as heavy as native cultivars grown in Korea. This useful characters were still inherited after grafting. However, characteristics of growth, leaf, flower, and flowering period were not different from those of native varieties. Therefore, it was very promising landscape woody plant, having large fruits in early fall season. The rooting rate of Korean dogwood was high by the IBA treatment. The optimum date for softwood cutting was on June 25 ∼ July 25 when the rooting rate was more than 80%. In addition. Korean dogwood was easily propagated by grafting. Therefore, new early maturing variety with large fruits, C. kousa var. ‘SKK 2-1’ is easily propagated by softwood cutting or grafting and then is a promising cultivar as a woody landscape plant.

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

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.3
• /
• pp.265-276
• /
• 2019

In our previous study, the LeNet3 model successfully classified images from the transverse surfaces of five Korean softwood species (cedar, cypress, Korean pine, Korean red pine, and larch). However, a practical limitation exists in our system stemming from the nature of the training images obtained from the transverse plane of the wood species. In real-world applications, it is necessary to utilize images from the longitudinal surfaces of lumber. Thus, we improved our model by training it with images from the longitudinal and transverse surfaces of lumber. Because the longitudinal surface has complex but less distinguishable features than the transverse surface, the classification performance of the LeNet3 model decreases when we include images from the longitudinal surfaces of the five Korean softwood species. To remedy this situation, we adopt ensemble methods that can enhance the classification performance. Herein, we investigated the use of ensemble models from the LeNet and MiniVGGNet models to automatically classify the transverse and longitudinal surfaces of the five Korean softwoods. Experimentally, the best classification performance was achieved via an ensemble model comprising the LeNet2, LeNet3, and MiniVGGNet4 models trained using input images of $128{\times}128{\times}3pixels$ via the averaging method. The ensemble model showed an F1 score greater than 0.98. The classification performance for the longitudinal surfaces of Korean pine and Korean red pine was significantly improved by the ensemble model compared to individual convolutional neural network models such as LeNet3.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.4
• /
• pp.58-65
• /
• 2002

This research was carried out to develop field treatment techniques of thinned small diameter softwood logs and less utilized hardwood logs using sap displacement method. In this paper, we report the feasibility of using transpiration method and butt-end method for the treatment of three softwood species and three hardwood species with preservatives, fire-retardant chemicals, and dimensional stabilizer. Butt-end method was effective as a field treatment technique compared to transpiration method when considered the treatability, easiness of treatment, productivity of treated wood, and environmental aspects related to chemical treatment, regardless of the combination of wood species and chemicals.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.4
• /
• pp.337-345
• /
• 2013

Log grading rules are essential tools to ensure the quality of logs in distribution structure. The rules should reflect the long experience and accepted usage practice in the market. A gap between the rules and market should be improved based on analysis of log qualities that produced and market demand. In this study more than ten millions logs which were produced by 5 Regional Forest Services in 2010~2011 period, were analyzed in their qualities including diameters and lengths by species. A proposal was driven to improve the current log grading rules in terms of log diameter classes and length. The followings are the summary of this study. Most of domestic softwood logs are belong to small diameter class of 100~160 mm, which imply the diameter classes of current log grading rules are immoderate. Distributions of log diameter shows distinctive patterns by species, which indicate a necessity of differentiated diameter classes by species in an improved rules. Lengths of logs in productions do not corresponding to the demands and preferences in sawmills. Therefore it is highly recommended to include log length term in an improved log grading system. Based on these findings, 6 log grading systems for 3 species groups of softwood are newly proposed to improve current log grading rules. Limits of log diameter and log length are also proposed for each log grading system.

• Journal of the Korean Wood Science and Technology
• /
• v.35 no.6
• /
• pp.31-42
• /
• 2007

To investigate the pyrolytic and anatomical characteristics of Korean softwood, Pinus densi-flora, Pinus rigida and Larix leptolepis, and hardwood, Acer palntatum, Fraxinus rhynchophylla and Quercus variabilis, chemical components analysis, TG-DTA (Thermogravimetric Analysis & Differential Thermal Analysis), MBA (Methylene Blue Adsorption) test and SEM observation were carried out. For TG-DTA, samples were carbonized up to $800^{\circ}C$ at the heating rate of $10^{\circ}C$/min under $N_2$ flows 1 l/min using thermogravimetric analyzer. Chemical component analysis of all samples resulted in typical contents of major wood component. In TG-DTA results, softwood showed higher char yield than hardwood, and lignin displayed the highest char yield among the major wood components. All samples showed typical TGA, DTG and DTA curves for wood pyrolysis except a few differences between softwood and hardwood. Content of lignin influenced its pyrolysis characteristics, while molecular structure of lignin affected not only the weight loss but also the yield of char. In MBA test results, MBA of softwoods was higher than that of hardwoods. Char of Pinus densiflora showed the highest MBA, but its degree was lower than activated carbon or fine charcoal about 23 and 4 times, respectively. SEM observation showed carbonization process preserves wood structure and retain the micro-structure of wood fibers.