• 한국습지학회지
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• 제16권2호
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• pp.245-250
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• 2014

본 연구는 제주도 곶자왈습지에서 서식하는 상록활엽수인 종가시나무의 지상부 생물량에 대한 상대생장식을 개발하기 위하여 수행되었다. 그 결과 독립변수가 DBH일 때, 줄기(Ws), 가지(Wb), 잎(Wl) 그리고 지상부(Wab)의 상대생장식은 각각 logWs=2.4042logDBH-1.3045, logWb=2.6436logDBH-1.6232, logWl=1.5428logDBH-1.3692 그리고 logWab=2.3324logDBH-0.9181이었다. 독립변수가 $D^2H$일 때, 줄기(Ws), 가지(Wb), 잎(Wl) 그리고 지상부(Wab)의 상대생장식은 각각 logWs=$0.853logD^2H-1.4252$, logWb=$0.8453logD^2H-1.5834$, logWl=$0.5328logD^2H-1.4073$ 그리고 logWab=$0.8453logD^2H-1.0327$이었다. 독립변수가 DBH일 때, 줄기, 가지 잎 그리고 지상부 상대생장식의 $R^2$값은 0.9873, 0.9711, 0.7979 그리고 0.993 이었고 독립변수가 $D^2H$일 때 0.9841, 0.9174, 0.7537 그리고 0.9876 이었다. 독립변수가 DBH인 상대생장식과 $D^2H$인 상대생장식은 모두 관측값과 예측값 사이에 통계적으로 유의한 차이가 없어 어느 상대생장식을 사용하더라도 결과에는 차이가 없었다.

• The Korean Journal of Ecology
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• 제27권1호
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• pp.27-33
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• 2004

Cryptomeria japonica plantation was monitored every year during 15 years from 1983 to 1997 for stem diameter and volume. The reciprocal equation, 1/Y = A + B/N, was applied to the relationship between cumulative volume Y and cumulative number N from the largest tree in the stand each year. The parameters A and B, which means respectively the reciprocal of an asymptotic value of total stand stem volume and the reciprocal of the maximum stem volume, are related by a power function. The power functional relationship between A and B derived a linear relationship of B-points ( $N_{B}$, $V_{B}$; $N_{B}$ = B/A, $Y_{B}$ = 1/2A) of each Y-N curve on log-log coordinates. The gradient of B-point line was so steep that the Y-N curve moved parallel upward year by year. The time trajectory of mean stem volume (W) and density ($\rho$) provided evidence in favor of the 3/2 power law of self-thinning, because the gradient of W - $\rho$ trajectory on log-log coordinates approximated to -3/2 at the final stage of stand development. On the basis of the results of Y-N curves and W - $\rho$ trajectory, the time trajectory of maximum stem volume $W_{max obs}$ and $\rho$ was derived theoretically. The gradient of $W_{max obs}$ - $\rho$ trajectory on log-log coordinates is calculated to be -0.6105 at the final stage. The gradient of $W_{max obs}$ - $\rho$ trajectory was steeper than that of W - $\rho$ trajectory at the early stage, while the former is gentler than the latter at the later stage.stage.e.age.e.

• Journal of the Korean Wood Science and Technology
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• 제23권2호
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• pp.47-54
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• 1995

This study was to measure the properties of logs and classify them by non-destructive methods. The purpose of this experiment was focused at mensurability of logs by non-destructive methods. The non-destructive instrument, Stress-Wave Timer 239A which was made by Metriguard in U.S.A., was used. The stress wave velocities of log's cross direction were measured and compared with three different methods; 1. with hammer, 2. with hammer and D.B.H. meter, 3. with manufactured instrument. Number of used logs were seven logs, which were classified by naked eye into six groups; very severe rot, severe rot, mild rot & knot, mild rot & check, mild rot, sound log, and in diameter were into three groups; large(57.4cm), medium(36~41.2cm), small(28.9cm) log. The results, which were classified by mensurability with non-destructive methods, were followed; 1. The stress wave velocities were very different between rot and sound log. So it meant the possibility of mensurability of logs by non-destructive method even if high standard error. 2. The stress wave velocities decreased with checks more than with rots, which meant the checks affected speeds more. 3. The stress wave velocities increased with knot. 4. The velocities with manufactured instrument showed lower standard error, so more accurate results than other methods. Especially the required labour decreased from 3~4 to 2 persons. 5. Finally, the mensurability showed more accurate results and made the classification of logs scientific.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.104-108
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• 2002

Nail withdrawal tests were conducted on clear wood of domestic small diameter logs. Nails were driven into the cross and longitudinal sections of each specimen, then nail withdrawal tests were performed. Nail withdrawal loads are strongly dependent on the direction of nail positions. The average load values for the nail withdrawal both in cross section and longitudinal section are higher in high specific gravity (SG) wood of sawtooth oak (Quercus acutissima Carr.) than those in low SG wood of Korean red pine (Pinus densiflora Sieb. et Zucc.) and pitch pine (Pinus rigida Mill.). The average ratio of the nail withdrawal loads for side-grain and end-grain are higher in the low SG wood than that in the high SG of wood. Both linear and non-linear regression analyses were conducted on nail withdrawal load with SG, good correlations were obtained between nail withdrawal load and SG.

• 한국산림과학회지
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• 제34권1호
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• pp.21-30
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• 1977

일본잎갈나무는 우리나라의 주요조림수종(主要造林樹種)으로 전국각지(全國各地)에 많은 조림지(造林地)와 임분(林分)이 있다. 이 수종(樹種)의 임분밀도관리(林分密度管理)의 지침(指針)을 마련하여 생산력예측(生產力豫則), 간벌계획(間伐計劃)과 수확량(收穫量) 사정(査定)을 용이하게 하는 일은 임업기술(林業技術)의 계량적(計量的), 생태적(生態的) 및 경제적(經濟的) 관점(觀點)에 대단(大端)이 의의있는 일로 생각 되었다. 이 연구(硏究)를 위해 정상적(正常的)으로 관리(管理)되고 있든 비정상적(非正常的)으로 관리(管理)되고 있든 최근(最近)에 간벌(間伐)한 흔적이 없는 임분(林分)에서 165개(個)의 표본(標本)을 조사(調査)하여 평균수고(平均樹高), 평균직경(平均直徑) 우세목수고(優勢木樹高), ha당(當) 본수(本數)와 1평균목(平均木)의 간재적(幹材積)을 산출(算出) 하였다. 이 연구(硏究)에 특(特)히 세장도이론(細長度理論)을 새로 도입(導入) 하였다. 이 이론(理論)에 대(對)한 실험적(實驗的) 검토(檢討)는 마(馬)와 Wardle, Shantz, Harms & Colline의 밀도시험결과(密度試驗結果)를 인용(引用)하여 증명한 바 있다. 임목(林木)의 상대생장(相對生長)은 일반적(一般的)인 logistic cnrve를 인용(引用)하고 공식(公式)은 모두 $Y=a{\times}b$를 대입(代入) 하였다. 각측정인자간(各測定因子間)의 관계(關係)는 아래와 같았다. 1. 세장도별(細長度別) 수고(樹高)와 밀고(密度)와의 관계(關係)-표(表) 1과 그림2 2. 세장도별(細長度別) 직경(直徑)과 밀도(密度)와의 관계(關係)-표(表) 1과 그림3 3. 세장도별(細長度別) 수고(樹高)와 단목간재적(單木幹材積)과의 관계(關係)-표(表) 3과 그림4 4. $D^2H$와 단목(單木) 간재적(幹材積)-$Log_eV=0.9569\;Log_eD^2H-9.8431$ 5. 밀도(密度)와 간재적(幹材積)-$Log_eV=9.5026-1.6800\;Log_eD$ 6. 밀도(密度)와 간재적(幹材積)-$Log_eV_{ha}=9.4911-0.6784\;Log_eD$ 7. 세장도별(細長度別) 수고계급(首告階級)에 응대(應對)한 간재적(幹材積)-표(表) 5 8. 세장도별(細長度別) 수고계급(首告階級)에 응대(應對)한 Ha당(當) 본수(本數)-표(表) 6 9. 세장도별(細長度別) 수고계급(首告階級)에 응대(應對)한 Ha당(當) 간재적(幹材積)-표(表) 7 이상(以上)의 과정(過程)을 거쳐 일본잎갈나무 임분밀도관리도표(林分密度管理圖表)를 제작(製作)하였다(그림 9). 이 관리표(管理表)의 정확도(正確度)를 검정하기 위하여 실측치(實測値)와 추정치(推定値)와의 관계(關係)를 보니 표(表) 8의 내용과 같이 오차(誤差)가 낮은편이었다. 이 도표(圖表)는 일본잎갈나무 임분(林分)의 밀도관리(密度管理)의 지침(指針)이 되리라 생각 된다.

• Journal of the Korean Wood Science and Technology
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• 제44권3호
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• pp.370-380
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• 2016

제주도 지역에서 소나무재선충병 피해를 받은 곰솔 원목의 이용확대를 위하여 열처리를 수행하였다. 열처리는 처리 원목의 중심부가 소나무재선충의 사멸온도인 $56^{\circ}C$를 30분간 유지하여야 한다. 곰솔 원목의 초기함수율과 말구지름은 각각 46% ~ 141%, 180 mm ~ 500 mm의 범위이고, 기본비중과 전건비중은 각각 0.47, 0.52이었다. $105^{\circ}C$ 조건에서 함수율과 말구지름에 따라 열처리에 소요되는 시간은 7.7 h ~ 44.2 h의 범위로 측정되었다. 다양한 함수율 및 지름을 갖는 곰솔 원목의 열처리 소요시간을 예측하기 위하여 열처리 진행 중 처리목 내부의 온도분포를 유한차분법을 적용한 2차원 열전달 해석을 통하여 제시하였다. 열전달 해석을 위한 목재의 열적 특성은 함수율에 따른 열전도계수와 비열을 적용하였으며, 자연대류와 강제대류를 합한 형태의 혼합대류에 의한 혼합대류계수를 적용하였다. 실험값과 예측 값의 오차는 3 ~ 45%의 범위로 분석되었다. 곰솔 원목에서 초기함수율이 50%이고, 말구지름이 200 mm, 300 mm, 400 mm인 경우, 예측된 열처리 소요시간은 각각 10.9 h, 18.3 h, 27.0 h이었다. 초기함수율이 75%일 때, 지름에 따라 각각 13.6 h, 22.5 h, 32.8 h이고, 초기함수율이 100%일 때, 지름에 따라 각각 16.2 h, 26.5 h, 38.2 h이었다. 이러한 열처리 소요시간의 예측방법에 소나무와 잣나무 등 다른 소나무재선충병 피해목의 물리적 특성을 적용하면, 함수율과 말구지름에 따른 열처리 소요시간을 제시할 수 있을 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제18권3호
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• pp.53-68
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• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• 한국산림과학회지
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• 제98권1호
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• pp.49-54
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• 2009

본 연구의 목적은 우리나라 참나무류 소경재의 활용용도별 수익성을 순수익(률)과 순소득(률)을 적용하여 상호 비교하였다. 참나무류 소경재의 활용용도는 표고버섯용 자목, 상황버섯용 자목, 톱밥, 숯, 펄프용 칩으로 하였다. 비용과 수입에 관한 정보 수집은 생산업체를 대상으로 면접 설문조사를 실시하였다. 분석 결과, 상황버섯용 자목으로 활용되었을 때 수익성이 가장 높게 나타났고, 다음으로 표고버섯용 자목, 톱밥, 칩, 숯으로 나타났다. 상황버섯용 자목으로 활용되었을 때 수익성이 높게 나타난 것은 높은 자본용역비와 생산 기술을 요구함에 따라 시장 경쟁이 아직은 높지 않아 상황버섯의 가격이 높기 때문이다. 자본회수 기간이 긴 표고버섯용 자목과 상황버섯용 자목으로 활용되었을 때의 수익성이 자본회수 기간이 짧은 톱밥, 숯, 칩에 비해 높게 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제13권3호
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• pp.41-48
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• 1985

In near future about 500,000 hectares of Japanese larch and pitch pine need thinning to improve crop-tree spacing and reasonable species composition in Korea. Although thinned trees show very little high quality wood, in fact, all the sawed products are suitable for construction and farming materials. Studies on the utilization of thinned small-diameter trees have been implemented in order to increase lumber yield and display the skeleton of farm buildings. The results obtained in this study were summarized as follows: 1. According to Korean Conifers Log Grading System, log grade 3 was 87.4 percent in Japanese larch bolts and 95.8 percent in pitch pine bolts from thinned trees. The ability to identify defects was essential for grading logs. 2. Cutting diagrams of sawing were developed for 1-sided sawing, 2-sided sawing and 3-sided sawing by small end diameter class of bolt and cutting sizes also were found to use effectively lumber with wane. 3. Lumber recovery of Pitch pine was a little higher than that of Japanese larch. The maximum lumber yields of pitch pine by sawing patterns were 87.2 percent for 1-sided sawing, 80.8 percent for 2-sided sawing an 64.1 percent for 3-sided sawing, up yield compared with 58.1 percent for 4-sided sawing. The lumber yield of 1, 2 and 3-sided sawing significantly was higher value than that of 4-sided sawing. 4. Lumber was inspected and graded. Lumber quality of diameter class 12cm was a little better than that of diameter class 8cm, but 90 percent of lumber in diameter c1ass 16cm fell into grade 3. The lumber grade was classified by Korean standard grades of confiers lumber. 5. Lumber from 1, 2 and 3-sided sawing was used to build the skeleton of a farm house ($53m^2$) and greenhouse ($60m^2$) in order to display more efficient use of small diameter trees from thinning 6. Total volume of timber for building a farm house was $8.1m^3$ of imported timber. Timber of $7m^3$, 70 percent of total volume would be substituted imported timber for domestic timber.

• 한국산림과학회지
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• 제97권5호
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• pp.485-491
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• 2008

This study was performed in 14 unthinned Mongolian pine (Pinus sylvestris L. var. mongolica Litvin) plantations in northeast China. Data were collected on 70 sample trees of different canopy position with diameter at breast height (DBH) ranging from 6.9 cm to 34.5 cm. Diameter and length of knots per whorl below the living crown were studied by different vertical levels divided by relative knot height (RHK) in this paper. Models taking DBH and height to the crown base (HCB) as independent variables were developed to predict knot diameter (KD) in a sample whorl. According to the vertical distribution tendency and range of sound knot length (KLsound), KLsound was modeled as multiple linear function of DBH, KD and relative knot height (RHK). The loose knot length (KLloose) was described as a function of DBH, KD and height above the ground for knots (HK) in a mixed log-linear model. Results from this study can provide abundant knot information so as to describe the knot size and vertical distribution tendency of Mongolian pine plantation.