• 한국환경과학회지
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• 제23권6호
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• pp.1075-1083
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• 2014

The objective of this study was to evaluate the effect of cutting types on microclimate and growth characteristics of afforested tree in Quercus acutissima stand after different types of cutting. The difference in temperature reaching $5.2^{\circ}C$ was shown in between clear cutting and selective cutting treatments. On July and August days with temperatures more than $35^{\circ}C$ often appeared in clear cutting stand. The values of VPD in July and August were higher than those in other months. Maximum VPD of 3.99 kPa was shown in clear cutting stand on May 23 as a prolonged rainless days appeared. However, VPD in selective cutting stand always stayed under 3.0 kPa throughout growing season. A higher intensity was shown in clear cutting and strip clear cutting stands, reaching to more than $1,600{\mu}mol\;m^{-2}s^{-1}$ at midday on early August, while that in selective cutting stand stayed about 1,500. In relative growth rate selective cutting stand showed a significantly higher relative growth rate in plant height than those in other cutting stands (p<0.05). The number of leaf in current-year branches significantly increased in selective cutting stand, whereas no increase was shown in clear cutting and strip clear cutting stands (p<0.05). In addition, relative elongation rate of current year branch also showed higher values in selective cutting stand compared with that in strip clear cutting stand (p<0.05). However, leaf mass per unit area (LMA) was higher in order of strip clear cutting, clear cutting, and selective cutting stands. From these results it is concluded that environmental conditions in clear cutting and strip clear cutting stands during growing season are more stressful to afforested tree species, resulting in lower relative growth in plant height, elongation of current-year branches, and leaf number per branch compared with those in selective cutting stand. Consequently, more data must be accumulated in the field to find out best cutting type in plantation considering the adaptational characteristic of each tree species varies with species and life span of tree is long.

• 한국응용곤충학회지
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• 제53권4호
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• pp.347-354
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• 2014

본 연구는 개벌 후 나비군집의 변화를 파악하기 위해서 실시하였다. 조사는 2011년 개벌지, 임도, 산림에서 5월부터 11월까지 선조사법을 실시했다. 조사결과, 총 32종 398개체의 나비가 관찰되었다. 먹이생태지위 범위와 서식처 유형에서의 나비 개체수는 개벌지가 산림보다 유의하게 높았다. 나비의 종수와 종다양도는 개벌지가 산림에 비하여 유의하게 높았다. 개벌지에서 환경부 취약종 기생나비와 은점표범나비의 많은 개체가 확인되었다. 본 연구결과, 개벌로 인하여 형성된 초지는 산림생태계에서 나비의 다양성을 높이는 중요한 역할을 한다.

• 한국산림과학회지
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• 제98권5호
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• pp.609-617
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• 2009

This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea, Pyrola incarnata, Linnea borealis and Maianthemum bifolium, completely disappeared and was replaced by sedge species, such as Carex duriuscula, C. lanceolata, C. pediformis, Poa attenuata and P. pratensis. During the research period, temperature increased by an average of $1.6^{\circ}C$ in burned stand and $1.7^{\circ}C$ in clear-cut stand compared to reference stand, but RH sharply decreased up to 15.7% in clear-cut stand. This result indicates that Larix sibirica stand became warmer and drier after forest fire and clear-cutting, and contributed to the abundance of sedge and grass species in the understory. Moreover, intense occupation of tall sedge grass after forest fire and clear-cutting had a vital role as obstacle on natural regeneration of Larix sibirica. The similarity of species composition between reference and burned stands was higher (73.6%) than between reference and clear-cut stands (63.8%). Soil moisture significantly decreased after forest fire and clear-cutting, and the extent of decrease was more severe in the clear-cut stand. The chemical properties at soil organic layer were significantly affected by forest fire and clear-cutting but not the mineral horizons. Inorganic nitrogen of the forest floor significantly decreased in the clear-cut stand ($1.1{\pm}0.4mg{\cdot}kg^{-1}$) than that of the burned ($4.5{\pm}2.3mg{\cdot}kg^{-1}$) and reference stands ($5.0{\pm}2.3mg{\cdot}kg^{-1}$). Available P of the forest floor significantly increased after fire, whereas it decreased after clear-cutting. These results indicate that existence of boreal understory vegetation, and changes in soil moisture and available P are distinct attributes applicable as ecological indicators for identifying forest degradation in Mongolia.

• 생태와환경
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• 제49권4호
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• pp.271-278
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• 2016

Forest clear-cutting operations influence biodiversity through habitat changes and food resource availability for inhabitant species. This study examined the effects of clear-cutting on forest arthropod communities. Arthropods were collected from two different forest treatment areas (clear-cut and control) in summer and autumn. In each treatment area, arthropods were sampled from both crown and ground surfaces using sweeping and pitfall trap methods, respectively. Then, the taxonomic order of the collected arthropod specimens was easily identified. Results indicate that arthropod abundance and number of taxa present were higher at ground surface than at crown levels in both clear-cut and control areas. At crown level, more homopteran species were present in clear-cut areas than in control areas in summer. At ground surface, populations of Isopoda and Opiliones were higher in control areas than in clear-cut areas, whereas numbers of Araneae, Orthoptera, and Hymenoptera were greater in clear-cut areas. Cluster analysis and principal component analysis showed distinct differences between clear-cut and control communities at crown level in summer and at ground surface in autumn. Thus, our results indicate that clear-cutting significantly influences arthropod communities, and higher taxa are valuable for conducting rapid biological assessments of ecosystem disturbances.

• 한국산림과학회지
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• 제112권3호
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• pp.331-339
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• 2023

본 연구는 목재수확 유형에 따른 종자 유입 특성을 구명하여 천연갱신에 의한 소나무 후계림 조성 기술의 기초자료를 제공하고자 수행되었다. 이를 위해 모수작업(단목모수, 군상모수) 및 개벌작업(대상개벌 10 mㆍ20 mㆍ40 m, 군상개 벌 20 mㆍ30 mㆍ40 m)을 실시하여 시험지를 조성하고, 2014년부터 6년간 천연갱신지의 종자 유입 특성을 분석하였다. 소나무 종자는 대부분 10~11월 갱신상에 유입되었으며, 종자 결실이 좋은 해에는 80% 이상이 10월에 유입되었다. 목재수확 유형별 연평균 종자 유입량은 군상 모수작업지(296천립/ha/yr), 20 m 군상 개벌작업지(291천립/ha/yr), 10 m 대상 개벌 작업지(281천립/ha/yr) 순으로 많았다. 유입 종자 분포 균일성은 20 m 대상 개벌작업지(52.2), 20 m 군상 개벌작업지(52.9), 10 m 대상 개벌작업지(56.1) 순으로 분석되어 벌채 면적이 상대적으로 좁은 10 m 대상 개벌작업지와 20 m 군상 개벌작업지가 종자 유입량 및 분포 균일성이 높은 것으로 나타났다.

• 한국공작기계학회논문집
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• 제12권3호
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• pp.89-95
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• 2003

This research analyzes the cutting mechanism of A1100-H18 of commercially pure aluminum by image processing in SEM(Scanning Electron Microscope) for the measurement of strain rate distribution near a cutting edge in orthogonal micro-cutting. The distribution is measured using various methods in order. The methods are in-situ observations of cutting process in SEM, inputting image data, a computer image processing, calculating displacements by SSDA(Sequential Similarity Detection Algorithm) and calculating strain rates by FEM. The min results obtained are as follows: (1)It enables to measure a microscopic displacement near a cutting edge. (2) An application of this system to cutting process of various materials will help to make cutting mechanism clear.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.604-607
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• 2003

This study investigates the micro-cutting of cemented carbides using PCD(polycrystalline diamond) and PCBN(polycrystalline cubic boron nitride) cutting tools are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the fracture of WC particles at the plastic deformation zone in orthogonal micro-cutting. And also to achieve systematic understanding, the effect of machining parameter on chip formation and machined surface was investigated, including cutting speed. depth of cut and various tool rake angle.

• 한국정밀공학회지
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• 제20권9호
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• pp.55-62
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• 2003

This paper investigates the micro-cutting of cemented carbides using PCD (polycrystalline diamond) and PCBN (polycrystalline cubic boron nitride) cutting tools are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the fracture of WC particles at the plastic deformation zone in orthogonal micro-cutting. And also to achieve systematic understanding, the effect of machining parameter on chip formation and machined surface was studied, including cutting speed, depth of cut and various tool rake angle. Summary of the results are shown below. (1) Three type of chip formation process have been proposed by the results of the direct observation in orthogonal micro-cutting of cemented carbide materials. (2) From the whole observation of chip formation, primary WC particles are crushed and/or fine grained in the shearing deformation zone. A part of them are observed to collide directly with a cutting edge of tool by following the micro-cutting. (3) Surface finish, surface morphology and surface integrity is good to obtain by cutting with PCD cutting tool compared with PCBN. (4) The machined surface has the best quality near the low cutting speed of 10${\mu}m$/sec with a cutting depth of 10 ${\mu}m$ using 0$^\circ$ rake angle and 3$^\circ$ flank angle in this condition, but it was found that excessively low speed, for example the extent of 1 ${\mu}m$/sec, is not good enough to select for various reason.

• 한국환경생태학회지
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• 제29권5호
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• pp.785-790
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• 2015

대면적 개벌의 대안으로서, 대상 개벌은 생산림지의 생태 조건 보전과 임분 재생을 모두 고려하는 작업법이다. 그러나 우리나라에서는 대상 벌채 기법의 적용 및 효율성에 대한 연구를 찾아보기 어렵다. 본 연구는 강원도 삼척에서 2012년부터 2014년까지 소나무림 대상 벌채 (10m, 20m 및 40m) 처리 전 후의 하층식생 반응 및 소나무 재생과 임분 환경 변화와의 상관성을 방형구법을 적용하여 조사 및 분석하였다. 하층식생 피도 및 종다양성은 대상 벌채 넓이에 상관없이 교목 종 및 광선호 종의 확장에 의해 증가하는 경향이었고, 신갈나무, 맑은대쑥 및 산딸기 등의 벌채 후 잔존 교목 및 광선호 종들의 활발한 증가가 관찰되었다. 대상 벌채 구역의 소나무 정착은 수관층 환경 (광량 및 수관열림도) 및 토양나출도와는 정의 상관, 그리고 하층식생 및 임상 목질잔해물의 피도와는 음의 상관을 나타내었다.

• 한국산림과학회지
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• 제95권4호
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• pp.501-506
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• 2006

개벌 후의 교목류 천연갱신 과정을 연구하기 위하여 개벌상의 태풍피해를 입은 북해도 시코츠코지역 침엽수 조림지에서 1년 후에 발생된 치수를 조사하였다. 그 결과 25종의 교목류 치수가 자라고 있었으며 치수밀도는 9.8주/$m^2$였다. 그 중 1년생 치수가 87%(8.6주/$m^2$)였으며, 비동물산포종(7.2주/$m^2$)이 동물산포종(1.4주/$m^2$)보다 5배 정도 많았다. 인접한 천연림으로부터 100m이내에서는 치수 밀도가 6주/$m^2$이상이었으며 150~250m에서는 2~9주/$m^2$였다. 비동물산포종은 천연림으로부터 멀어질수록 치수발생량이 감소하였으며 동물산포수종에 비하여 밀도 변이폭이 크게 나타났다. 개벌 후 교목류의 천연갱신에서는 자작나무류와 같은 선구수종이 우점할 확률이 높다. 따라서 수종구성을 다양하게 유지하기 위해서는 경쟁을 완화시키는 보육작업이 필요하다.