• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.168-176
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• 2015

This study was performed to investigate the effects of heat treatment the on mechanical properties of two species of wood under different heating conditions including at $180^{\circ}C$ for 12 h and 24 h, and at $210^{\circ}C$ for 3 h and 6 h. Two species of wood, Pinus densiflora and Larix kaempferi, were exposed to different heat treatments to assess the effects on the volume change, bending properties in static and dynamic mode and compressive strength. The results showed heat treatment caused significant changes in mechanical properties such as the static and dynamic moduli of elasticity ($MOE_d$ and $MOE_s$), and the modulus of rupture (MOR). The volume of the wood after heat treatment decreased as the heating temperature and time were increased. The bending strength performance of the wood after heat treatment decreased as the heating temperature and time were increased. The effect of heat treatment at a high temperature on the bending MOR was greater in both species than that for a long time. However, the compressive strengths of all the heat-treated samples were higher than the control sample. Furthermore, highly significant correlations between $MOE_d$ and MOR, and $MOE_s$ and MOR were found for all heating conditions.

• Journal of the Korean Wood Science and Technology
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• v.48 no.1
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• pp.41-49
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• 2020

Jabon (Anthocephalus cadamba) is a fast-growing wood species that is widely utilized for light construction and other purposes in Indonesia. The objectives of the current study were to determine the effects of monoethylene glycol (MEG) and SiO₂ nanoparticles (nano SiO₂) impregnation treatment on the dimensional stability and density of jabon wood and to identify the characteristics of impregnated jabon wood. Wood samples were immersed in water (as untreated), MEG, 0.5% MEGSiO₂, then impregnated by applying 0.5 bar of vacuum for 60 min, and then applying 2.5 bar of pressure for 120 min. The results showed that impregnation with MEG and Nano SiO₂ had a significant effect on the dimensional stability of jabon wood. Polymers can fill cell walls in wood indicated by increasing weight percentgain, antiswelling efficiency, bulking effect, and density, then decreasing in water uptake value. Jabon wood morphology by using SEM showed that MEGSiO₂ polymers can cover part of the pitsin the wood vessel wall of jabon. This finding was reinforced by EDX results showing that the silicon content was increased due to the addition of SiO₂ nano. The XRD diffraction pattern indicated that MEGSiO₂ treatment increased the degree of crystallinity in wood samples. Overall, treatment with 0.5% MEGSiO₂ led to the most improvement in the dimensional stability of 5-year-old jabon wood in this study.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.88-95
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• 2004

The purpose of this study is to identify the species of wood members used in the Keunjungjeon Hall, main building of the Kyungbok palace in Seoul. The total 144 samples consist of 52 from pillars and 92 from other wood members. Only two species were identified, which were Abies holophylla Max. (needle fir) and Pinus densiflora Sieb. et Zucc. (Japanese red pine). For the pillars, A. holophylla were more abundantly used than P. densiflora. Among 20 outer pillars ('Pyeongju'), 11 were A. holophylla, and 9 were P. densiflora. Among 12 inner pillars ('Naejinkoju'), 7 were A. holophylla, and 5 were P. densiflora. Among 4 inner corner pillars ('Gwikoju'), 3 were A. holophylla and 1 was P. densiflora. For 92 other wood members, only 2 purlins were A. holophylla and the others were all P. densiflora. The results suggest that the common opinion 'Palace buildings of Korea are made from red pine woods' should be corrected. We think that fir logs might be used for the pillars instead of pines because long and straight pines were not available during 1860s due to heavy utilization of pines as construction and fuel materials in the late Chosun period.

• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.265-276
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• 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 Conservation Science
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• v.2 no.2 s.2
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• pp.15-24
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• 1993

To understand the morphological change of ancient woods, samples classified by cell type, burial environment and species were collected and observed using microscopy. Decay of wood by cell type could classified into two types. First, degraded secondary wall was formed granular residues in $S_2$ layer and was remained $S_3$ layer and compound middle lamella. Second, the cell wall was slightly degraded and cracked in secondary wall. A gradual thinning of cell wall was occured. The compound middle lamella was separated from secondary wall. The resistance of degradation is increased at vessels, parenchyma, and tracheid and wood fiber in the order named. The type of degradation by species could be classified into four types. Overall degradation type; the degradation of cell wall is usually heavy and the extent of degradation Varies by part of the same sample. Partial degradation type ; this type shows severely different decay type by part of the sample. Nondegraded cells were mixed with degraded cells on the same sample. Erose degradation type ; thinning of the cell wall was occoured and the degradation type was different by part. Slight degradation types ; secondary wall was slightly degraded, cracked and separated from compound middle lamella. Considering different type of burial environment, dry wood was similiar to sound wood and slightly decayed. Waterlogged and peat burial wood was heavilydecayed. Between species of under the same environment, decay type and extent were diferentiated from each other.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.58-65
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• 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
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• v.34 no.6
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• pp.96-103
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• 2006

A simple method for identifying of ectomycorrhizal fungi was presented, using the polymerase chain reaction (PCR) to amplify the ITS (Internal transcribed spacer) regions of the nuclear ribosormal repeat. The sequences analyzed 6 species, Pisolithus tinctorius, Chroogomphus rutilus, Leucogyrophana pinastri, Suillus granulatus, Lactarius laeticolorus, and Suillus bovinus at hongreung forest, and analysed 10 species, Craterellus lutescens, Thelephoroid mycorrhizal, Lactarius quieticolor, Tricholoma matsutake, Lactarius chrysorrheus, Sarcodon aspratus, Russula versicolor, Suillus luteus, Tricholoma terreum, and Amanita vaginata at hongcheon forest. Finally, the amplification by PCR with ITS1-ITS4 primers offers good results over classical identification for ectomycorrhizal fungi species.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.1-6
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• 1999

Hundred pieces of peat woods(ca. 2500 years old) were excavated in 1995 at Hyunwhari, Pyungtaek in the west-central coast of the Korea Peninsula. Among them, 63 samples representing 21 trenches were selected for the species identification. Because most peat woods were rotten by fungi for long period, only 27 samples could be identified. Due to the deteriorated structure of peat woods, all samples were embedded in PEG(polyethylene glycol 2000) and then sectioned using a rotary microtome. Major species were Alnus spp.(55.6%), Fraxinus spp.(33.3%) and Quercus (Lepidobalanus)(11.1%). No conifers were found. The species composition indicates that the sample region was a swamp or lakeside, which appeared to be formed because of the sea-level rise after last-glacial period.

• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.101-109
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• 2019

This paper examines the classification of five coniferous species, including larch (Larix kaempferi), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa), using near-infrared (NIR) spectra. Fifty lumber samples were collected for each species. After air-drying the lumber, the NIR spectra (wavelength = 780-2500 nm) were acquired on the wide face of the lumber samples. Soft independent modeling of class analogy (SIMCA) was performed to classify the five species using their NIR spectra. Three types of spectra (raw, standard normal variated, and Savitzky-Golay $2^{nd}$ derivative) were used to compare the classification reliability of the SIMCA models. The SIMCA model based on Savitzky-Golay $2^{nd}$ derivatives preprocessing was determined as the best classification model in this study. The accuracy, minimum precision, and minimum recall of the best model (PCA models using Savitzky-Golay $2^{nd}$ derivative preprocessed spectra) were evaluated as 73.00%, 98.54% (Korean pine), and 67.50% (Korean pine), respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.46-46
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• 1991

Adequate regrowth control of weeds and shrubs has been one of the important problem for pasture establishment by overseeding on reclaimed forest hilly land. This experiment was carried out on sloping shrub land near Anseong, Gyeonggido to evaluate the effects of herbicide application on growth control of native weeds, shrubs and trees. We evaluated 63 different weeds and wood species in the trials, which are grown common in korean forest. Buthidazol and 4 other herbicides (sodium chlorate, glyphosate, U-46 and gramoxone) were sprayed each at two application rates during the period of the most intensive growth, on 20 July 45 days before overseeding of pasture species. Glyphosate and sodium chlorate gave excellant control of growth of all species. However. Uncus effusus, Carex heterostachya, Polygonatum humile, Rubus corchorifolius, Lonicera coeralea and Rhododendron mucronulatum were classified as a tolerant weed and wood species to herbicides. Herbicide buthidazol showed also successive control of regrowth of weeds and wood species. But buthidazol was evaluated as a none available herbicide for use in pasture establishment. because o! their long persist of toxic herbicide residue in soils after treatments. Herbicide U-46 and gramoxone had almost no effect on regrowth of shrubs and tree species