• 임산에너지
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• 제25권2호
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• pp.49-54
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• 2006

국산 침엽수재의 구조재 활용에 필요한 등급구분을 위해 소나무, 잣나무와 낙엽송 $2{\times}6"$ 부재에 대해 초음파를 이용한 비파괴 방법을 적용하였다. 정적 탄성계수와 초음파 시험에 의한 동적 탄성계수의 상관관계를 나타내는 k-factor는 소나무의 경우 1.0602, 잣나무 1.0013, 낙엽송 1.2320로 나타났다. k-factor를 적용할 경우 비파괴방법에 의한 동적 탄성계수 측정에 의해 침엽수 구조부재 등급구분이 가능할 것으로 판단되었다. 기계응력 등급구분에서 소나무는 E9 이상의 등급이 전체의 76%인 반면 잣나무는 E7 이상의 등급이 전체의 85%, 낙엽송은 E11 이상의 등급이 68% 분포하였다. 정적 탄성계수와 휨파괴계수(MOR)의 상관관계도 비교적 높게 나타나 이를 동적 탄성계수로부터 추정한 k-factor와 연계할 경우 초음파 비파괴 등급구분 방법에 의해 국산 침엽수재의 휨강도 성능평가가 가능할 것으로 판단되었다.

• 한국산림과학회지
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• 제97권1호
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• pp.45-52
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• 2008

본 연구의 목적은 MDF산업의 지속적이고 안정적인 육성을 위해 MDF 생산장기전망에 의한 침엽수 원목공급방안을 제시하고자 하는 것이다. 이를 위해 고전적최소자승법(Ordinary Least Squares Method, OLS)을 이용하여 장기공급함수모델을 개발하였다. 그 결과 MDF의 국내 생산량이 2005년 1,653천$m^3$에서 2050년 2,041천$m^3$으로 증가하는 것으로 전망되었다. 국산 침엽수원목의 MDF 원자재 공급량은 2050년에 2,041천$m^3$의 MDF를 생산하는데 약 1,355천$m^3$이 소비되는 것으로 나타났다. 현재 MDF원자재로 사용되고 있는 리기다소나무의 경우 2050년도에 국산재 원목공급에 필요한 벌채면적은 10,828ha인 것으로 추정되었다. 낙엽송은 9,160ha의 벌채면적이 필요한 것으로 추정되었다. MDF생산의 국산원목사용량의 구성비 시나리오를 35%, 45%, 55%의 3가지로 나누어서 2050년에 침엽수 수종별 예상 연간 벌채량과 총 조림면적을 구하였다. 벌채면적을 기준할 경우 낙엽송을 식재하는 것이 유리하지만 각 수종별 용도 및 생육적 특성이 있으므로 MDF원자재를 공급하려고 하면 어느 정도 이러한 점을 고려한 조림정책이 이루어져야 할 것이다. 그리고 리기다소나무 벌채 후 활엽수 조림정책을 실시하더라도 현재의 MDF 보드산업의 안정적인 육성을 위해서는 MDF의 원자재 공급에 필요한 침엽수종의 일정 면적이 유지 및 관리되는 것이 필요하다.

• 한국산림과학회지
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• 제95권2호
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• pp.203-208
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• 2006

This study compared the roundwood demand prediction accuracy of econometric and time-series models using Korean data. The roundwood was divided into softwood and hardwood by species. The econometric model of roundwood demand was specified with four explanatory variables; own price, substitute price, gross domestic product, dummy. The time-series model was specified with lagged endogenous variable. The dummy variable reflected the abrupt decrease in roundwood demand in the late 1990's in the case of softwood roundwood, and the boom of plywood export in the late 1970's in the case of hardwood roundwood. On the other hand, the prediction accuracy was estimated on the basis of Residual Mean Square Errors(RMSE). The results showed that the softwood roundwood demand prediction can be performed more accurately by econometric model than by time-series model. However, the hardwood roundwood demand prediction accuracy was similar in the case of using econometric and time-series model.

• Journal of the Korean Wood Science and Technology
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• 제43권1호
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• pp.25-35
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• 2015

본 연구에서는 국산 침엽수재의 육안 등급구분과 허용응력설정에 관한 국내의 학술논문을 정리하였다. 국립산림과학원 고시(KFRI 1995-27, KFRI 2000-39, KFRI 2007-3, KFRI 2009-1)를 활용하여 국산 낙엽송재의 육안 등급 구분한 연구를 비교한 결과 등급구분 비율이 연구자마다 상이했다. 보다 신뢰할 수 있는 등급구분 분류를 위해서 공증된 목재이용 기관에서 숙련된 연구자에 의한 등급구분을 시행하여야 할 것으로 사료된다. 허용응력설정에 관한 연구를 고찰한 결과, 연구자 마다 허용응력산출 방법이 ASTM D 245, KS F 2152, JAS 1990으로 모두 상이했다. 이는 침엽수 구조용재(KS F 3020)에서 기준허용응력을 제시하고 있지만 허용응력을 산출하는 명확한 방법이 제시되어 있지 않기 때문인 것으로 나타났다. 따라서 공식적인 허용응력 결정방법이 제정되어야 할 것으로 사료된다.

• 한국가구학회지
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• 제26권3호
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• pp.222-228
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• 2015

To evaluate the natural decay durability of valuable domestic softwoods which are used for preservative treatment in our country, we carried out decay test by European standard method. Of all test wood species, Japanese larch (Larix leptolepis) showed slightly high natural decay durability compared to other 4 wood species, Japanese red pine (Pinus densiflora), pitch pine (Pinus rigida), Japanese cedar (Cryptomeria japonica), and scots pine (Pinus sylvestris). However, all of evaluated domestic softwood species in this study caused high weight losses over about 30% in heartwood by test fungus, Poria placenta. We can hardly expect a good natural decay durability from these softwood species. According to the classification of the natural durability of European standard (EN 350-1), they are classified into "Not durable" or "Slightly durable". Therefore, if using these softwoods as exterior materials, we must do preservative treatment to ensure durability.

• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.55-59
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• 2003

The fixation and leaching characteristics of chromated copper arsenate (CCA Type C) and chromium- copper-fluoride-zinc (CCFZ) in domestic softwood (Japanese red pine, Korean pine, and Japanese larch) sapwood were investigated using the expressate method to follow chromium fixation and the American Wood-Preservers' Association (AWPA) leaching procedure to determine leaching properties after fixation. The rates of fixation were affected by preservative types; CCA was fixed much faster than CCFZ for all species evaluated. There were definite differences in the fixation rates of different species, with Korean pine requiring shorter to fix than the other species evaluated. Chromium fixation was greatly enhanced by elevated temperatures, and fixation time can be estimated according to fixation temperatures applied. The percentage of arsenic and zinc leached from domestic softwoods was relatively high compared to chromium and copper, indicating that there is still a relatively high unfixed arsenic and zinc components after complete chromium fixation in CCA-and CCFZ-treated samples, respectively.

• 한국가구학회지
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• 제19권3호
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• pp.156-162
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• 2008

Three major domestic softwoods, Korean red pine, Korean pine and larch, were heat-treated at $220^{\circ}C$ and for various treatment times for color changing. A new heat treatment equipment was developed for this study and was revealed working well for changing the colors of the three softwoods. The color difference index of 15 was obtained after 8 hours for Korean red pine and Korean pine, and 10 hours for Larch. The correlations of brightness, redness and yellowness with treatment time were different between species.

• Journal of the Korean Wood Science and Technology
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• 제24권1호
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• pp.11-16
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• 1996

The purpose of this paper is to present a summary of assignment design values according to domestic softwood structural lumber grading rules. Allowable stresses for visually graded lumber were determined from basic data on small. clear specimens. The data corrected for variability such as natural defects and other factors. The procedure adopted by Japan was used for assigning allowable design values. Strength ratios in relation to each defect were taken from ASTM D 245-81. Korean pine(Pinus koraiensis S. et Z.), Korean red pine(Pinus densiflora S. et Z.), Japanese larch(Larix leptolepis Gordon) and Needle fir(Abies holophylla Max) were applied to this study. The calculated allowable stresses were same in Korean pine and Korean red pine. These values were highest in Japanese larch lowest in Needle fir. So, it is desirable for these species to be classified into different catagories Species Group. However, accurate comparison in design values on lumber grading rules among U.S., Japan and Korea was somewhat difficult. And full scale testing will be necessary for accurate determination of the correction factors to setting up design values.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.399-408
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• 2017

Research on the rapid and accurate prediction of physical properties of wood using near-infrared (NIR) spectroscopy has attracted recent attention. In this study, partial least squares analysis was performed between NIR spectra and air-dried specific gravity of five domestic conifer species including larch (Larix kaempferi), Korean pine (Pinus koraiensis), red pine (Pinus densiflora), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa). Fifty different lumbers per species were purchased from the five National Forestry Cooperative Federations of Korea. The air-dried specific gravity of 100 knot- and defect-free specimens of each species was determined by NIR spectroscopy in the range of 680-2500 nm. Spectral data preprocessing including standard normal variate, detrend and forward first derivative (gap size = 8, smoothing = 8) were applied to all the NIR spectra of the specimens. Partial least squares analysis including cross-validation (five groups) was performed with the air-dried specific gravity and NIR spectra. When the performance of the regression model was expressed as $R^2$ (coefficient of determination) and root mean square error of calibration (RMSEC), $R^2$ and RMSEC were 0.63 and 0.027 for larch, 0.68 and 0.033 for Korean pine, 0.62 and 0.033 for red pine, 0.76 and 0.022 for cedar, and 0.79 and 0.027 for cypress, respectively. For the calibration model, which contained all species in this study, the $R^2$ was 0.75 and the RMSEC was 0.37.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.6-12
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• 1998

Test results of domestic softwood lumber were presented to examine the notch effect of beams and compare to present AIJ(Architecture Institute of Japan) formula in notched wood member especially positioned in bottom side (tension side) of a beam. Notched lumber was tested under following condition : each specimen supported simply, and subjected to third-point loading at points of 1/3 of the span length. Notch was located opposite side to loading direction and notch depth were 1/6, 1/4, 1/3 of beam depth. Deflection and load were measured by digital dial guage each in 25kgf increment. Bending test results were as follows; Mpro/Mmax range (proportional and maxium bending moment ratio in notched beam) was 0.5 - 0.65. It was considered that maxium bending moment was about 1.5 times to proportional bending moment in notched beam and showed same tendency in the test result of ordinary wood specimens. AU standard formula for the tension side notch, Mmat = 0.6 ${\times}$ (Zo $\sigma$), the constant 0.6 was suitble for notch ratio(notch depth to beam depth) 1/6, but this ratio for 1/4, and 1/3 was not. So it is preferable to accept smaller value than 0.6 for notch ratio more than 1/3. These experiment results showed critical effect in tension side notched wood beam especially in greater than notch ratio 1.3 of wood beam. From the above results, it is recommened to revise design formula adoptable to domestic wood constructon member with tension side notched member.