• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.108-116
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• 2010

This paper explains the effects of wood drying on treatability (as determined by water uptake) of Japanese red pine (Pinus densiflora S. et Z.) at the sevenmoisture content (MC) levels above and below the fiber saturation point (FSP). According to the experimental results, it was found that water uptake (as the percentage of void volume filledwith distilled water, VVF%) was influenced by level of moisture content and percentage of void volume filled was improved effectively by kiln drying process. A significant relationship between moisture content and treatability was established. Permeability and liquid uptake were decreased above the FSP due to the effect of the less void space available in wood. Even though increased liquid uptake was observed at lower moisture content, no significant differences was observed moisture content below 20%. Therefore, this species need to be initially dried below FSP before treated with liquids. But drying moisture content below 10% might not be economical for the commercial purpose comparing drying the wood between 10 and 20% moisture content. The result of this study inferred that the treatability of pine wood can be improved by reducing the moisture content up to a certain level of 10~20% for allowing better performance.

• 한국환경복원기술학회지
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• 제14권4호
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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.

• 한국환경복원기술학회지
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• 제11권4호
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• pp.46-56
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• 2008

This study examined the natural restoration of vegetation through monitoring of the development of a vegetation community from 2006 through 2007 after a forest fire. Approximately 5,000 $m^2$ in a forest near Topyeon-ri, Kangnae-myeon, Chungcheongbuk-do with Japanese red pine (Pinus densiflora) forest and its floor vegetation had been completely burned by a fire in April 2005. This area and another nearby Japanese red pine forest were selected as the experiment site and the control site, respectively. Vegetation survey was conducted at the experiment site and the control site. A seed bank experiment was carried out in the greenhouse to examine underground vegetation. Effective microorganism(EM) was applied to the seed bank experiment to estimate its effects on the direction of ecological succession. According to the results, a total of 36 plant species including shrub and herbaceous species were discovered in the experiment site. Quercus serrata, Lespedeza cyrtobotrya, and Castanea crenata, Rubus crataegifolius, Oplismenus undulatifolius, and Carex lanceolata were among the most abundant species. Biomass in the experiment site reached 2.4 times biomass than those in the control site, indicating the productivities of shrub and herbaceous layers are better in the experiment site. According to the result of the soil seed bank experiment of the experiment site, a total of 182 plants of 14 species were recorded. In addition, a total of 13 plants of 2 species were found from soil seed bank of the experiment site applied by EM. If EM is applied to the burned site, it will control the budding of herbaceous plants, creating the gap between herbaceous plants. This loss of competition is expected to help the restoration of trees in the burned area.

• 농업과학연구
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• 제48권4호
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• pp.753-760
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• 2021

This study was carried out to discover suitable packaging methods during the cold or frozen storage of sawtooth oak and Japanese larch seedlings, which are major afforestation tree species in Korea. The weight loss rate of sawtooth oak was lower under frozen storage at -2℃ (maximum, 33.7%) than under cold storage at 2℃ (maximum, 61.0%). A film liner treatment inside the packaging box effectively suppressed the increase in the weight loss rate. For the sawtooth oak containerized seedlings, when stored at -2℃, the rate of weight loss was 17.9 to 25.4% in the untreated group and less than 1% in the film liner treatment group. Similar results were observed with Japanese larch. After two months of freezing at -2℃, both species maintained a low index of 1.0 - 1.1 with regard to the degree of shoot desiccation of containerized seedlings, and there was no significant difference between the treatments. On the other hand, the chlorine dioxide treatment could more effectively reduce the occurrence of mold and shoot desiccation than a PE single treatment in bare-root seedlings. According to these results, it was concluded that frozen storage is generally suitable as a means of long-term storage compared to cold storage of sawtooth oak and Japanese larch. A chlorine dioxide treatment at 20 ppm was effective for maintaining seedling quality levels during storage, demonstrating the good effect of suppressing the occurrence of shoot desiccation and the occurrence of mold.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.417-430
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• 2020

4종의 판상형 목재제품의 방염제 도포량과 침지시간에 따른 방염성능을 분석하기 위하여 소방청의 방염성능기준에 따라 목재제품의 탄화길이와 탄화면적을 측정하였다. 잣나무 합판, 낙엽송 합판, 편백 판재, 타공처리된 자작나무 합판에 자체 개발된 방염제를 각각 300, 500 g/㎡씩 도포하고 방염처리되지 않은 시험편과 비교하였다. 일반적으로 방염제의 도포량이 증가함에 따라 탄화길이와 탄화면적이 감소하여 방염성능이 증가하는 경향을 나타냈으나, 낙엽송 합판을 제외하고 탄화길이와 탄화면적의 감소량이 크지 않았다. 타공처리된 자작나무 합판의 침지시간에 따른 방염성능은 60분의 침지시간까지 양의 상관관계를 나타냈으나, 그 이후 점차 완만해지는 경향을 보였다. 방염제의 도포량과 침지시간에 따른 목재제품의 방염성능은 추후 방염성능 기준에 맞는 불연·준불연 목재의 생산을 위한 기초자료로 이용될 것으로 기대된다.

• 한국산림과학회지
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• 제99권3호
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• pp.344-352
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• 2010

소나무 채종원내 클론 간 교배양식을 구명하기 위해서 4개의 nSSR 표지와 6개의 cpSSR 표지를 이용하여 소나무 채종원 내에서의 타가교배율, 기여 화분친 수, 화분오염율을 산출하였다. cpSSR haplotype에 근거한 타가교배율은 94~100%로, 평균 98.9%의 타가교배율이 산출되었다. nSSR genotype에 근거한 타가교배율은 90.3~100%로, 평균 95.9%의 타가교배율이 산출되었다. 별개의 DNA 표지분석에서 자가교배로 확인 되었던 종자들을 두 표지를 동시에 비교하여 확인한 결과 타가교배 종자로 최종 확인되었다(누적 타가교배율 100%). 화분오염율은 최소 43.6%(강원10)에서 최대 56.4%(강원12)로 평균 48.9%로 계산되었다. 종자의 cpSSR haplotype을 근거로 확인한 기여 화분친은 경북38에서 21개로 최대치가 확인되었으며, 강원10에서 13개로 최소치가 확인되어 평균 16.2개의 기여 화분친이 확인되었다. 결론적으로, 안면도 소나무 채종원 ’77단지내 클론간 높은 타가교배율이 확인됨으로써 채종원산 종자의 유전적 안정성을 기대할 수 있으며, 안면도 소나무 채종원 '77단지 내 교배양식 분석을 통해서 확인된 결과가 향후 전진세대 채종원 조성 및 관리에 유용한 정보를 제공할 것으로 기대된다.

• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.85-93
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• 2010

Japanese cedar has low density and poor mechanical performance. Manufacturing glue-laminated timber (glulam) is the best way to compensate for its poor mechanical performance. The Korean Standard (KS) confines outermost lamina of glulam to higher grade than E8, but the yield of higher than grade E8 from logs is only 6.5%. Therefore, the aim of this study is to investigate the possibility of non-Korean-Standard glulam in structural applications. Allowable stresses determined by both hand-calculation and Monte-Carlo simulation show a higher allowable stress than that of the KS-standard glulam of 6S-22B. In the Korean Standard (KS), knot characteristics are not taken into account. Japanese cedar has relatively small knots. We believe that the small knots in Japanese cedar contribute to a higher allowable stress than the KS-standard glulam would predict. The species classification of KS is required to be further subdivided into sub-species groups based on knot characteristics.

• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.163-171
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• 2011

Because Japanese cedar shows lower mechanical performance, glued-laminated timber (glulam) can be a better way to utilize Japanese cedar for structural purpose. However, low yield of higher grade lamination from log makes it difficult to design structural glulam. This study was aimed to increase the yield of higher grade lamination and provide higher efficiency of manufacturing structural lamination by ultrasonic log sorting technology. Logs were sorted by an existing log grading rule regulated by Korea Forest Research Institute (KFRI). It was found that the KFRI log grading rule contributed to finding better logs in viewpoint of the volumetric yield and it can reduce the number of rejected lumber by visual grading. However, it could not identify better logs to produce higher-grade products. To find an appropriate log-sorting-method for structural products, log diameter and ultrasonic time of flight (TOF) for the log were considered as factors to affect mechanical performance of resulting products. However, it was found that influence of log diameter on mechanical performance of resulting products was very small. The TOF showed a possibility to sort logs by mechanical performance of resulting products even though a coefficient of correlation was not strong (R = 0.6). In a case study, the log selection based on the ultrasonic TOF of the log increased the yield of the outermost tension lamination (E8 or better grade, KS F 3021) from 2.6% to 12.5% and reduced LTE5 (lower than E5 grade) lamination from 43.6% to 10.3%, compared with the existing KFRI log grading rule.

• Journal of the Korean Wood Science and Technology
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• 제35권4호
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• pp.1-8
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• 2007

목재의 방향별 내부수분이동계수와 표면방사계수를 측정하기 위하여 2.5 (방사방향) ${\times}$ 2.5 (접선방향) ${\times}$ 2.5cm (섬유방향)의 낙엽송 정육면체 시편을 제작하였다. 수분이동방향과 직교하는 단면을 제외한 나머지 4면을 파라핀테이프와 고무테이프를 이용하여 코팅한 후, 70, 50, $30^{\circ}C$의 3가지 온도조건과 30, 60%의 2가지 상대습도 조건에서 건조시키면서, 목재 내부와 표면에서의 수분이동을 평가하였다. 자유수 유동과 결합수 및 수증기의 확산에 의한 내부수분이동계수는 고온조건에서 크게 나타났으며, 섬유방향이 횡단방향에 비하여 6배, 횡단방향에서는 방사방향이 접선방향에 비하여 1.2배 정도 큰 값을 보였다. 표면방사계수는 온도가 상승하고, 표면함수율이 감소함에 따라 증가하였다. 본 연구 결과를 이용하여 비평형상태에서 낙엽송재 내 함수율 분포변화와 증발수분량을 예측할 수 있으리라 기대된다.

• Journal of Forest and Environmental Science
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• 제30권4호
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• pp.383-392
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• 2014

In this study, we investigated the Fukiage sand dunes of southern Kyushu, Japan. We surveyed the status of recovery of coastal Japanese black pine forests damaged by pine wilt disease and their disaster prevention capability. We placed two transects: Transect 1, in an area that was severely damaged (80-90% damage rate) by pine wilt disease, and Transect 2, in an area that was mostly undamaged (<10% damage rate). Then, we installed survey lines, carried out vegetation surveys, and measured the depth and pH of humus soil. The survey lines were placed perpendicular to the coastline from the top of the fore-dune to the inland area, and divided into five 50 m sections. Before the point 100 m inland from the top of the fore-dune, the number of invasive hardwoods and of Japanese black pines were small because of the poor growth environment in both transects. Past the 100 m point, the species and number of Japanese black pines and broad-leaved trees increased further inland because the growth environment improved. In addition, the recovery metrics of tree height, diameter at breast height, age, and number in Transect 1 were much lower than those in Transect 2, and the basal area of broad-leaved trees and the depth of humus soil in Transect 1 were lower than in Transect 2, and the soil pH of humus soil in Transect 1 was higher than that of Transect 2. The shape ratio of the Japanese black pine forests indicated that they were insufficient for disaster prevention. Therefore, in order to fully promote the disaster prevention capability of coastal Japanese black pine forests, we should not only focus on prevention of pine wilt disease but also undertake continuous control efforts taking into consideration the sound growth environment such as appropriate density and soil management and removal of invasive broad-leaved trees.