• Journal of Ecology and Environment
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• 제30권3호
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• pp.251-255
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• 2007

Self-thinning was measured in Salix communities on Bam Island in Seoul at various age stages. $D^2H$ was used to estimate tree biomass, where D is stem diameter at breast height or 10 cm height for plants with height <1.5 m, and H is height. A log-log plot of density versus $D^2H$ and correlation analysis indicated a significant relationship between density and biomass with equation 'log $D^2H$ = -1.27 log N + 7.06'. This indicates that self-thinning affects biomass in the Salix community with -1.27 as the thinning coefficient. If we assume a thinning exponent -3/2, then the allometric coefficient of the equation, log w = a log $D^2H$ + b, is 1.18. This is much higher than that for any other species studied in Korea. There were statistically significant relationships between age and density and between age and basal area and these relationships suggest guidelines for transplantation of willows and for the assessment of Salix community restoration projects in riverine wetlands based on standard density, basal area, and age. The results of this study may also increase understanding of succession processes in Salix community restoration in riverine wetlands.

• 한국약용작물학회지
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• 제23권3호
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• pp.198-206
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• 2015

This study was conducted to investigate the effects of sowing density, number of seeds sown per hole, and thinning treatment on growth characteristics and disease occurrence in Panax ginseng under direct sowing cultivation in a blue plastic greenhouse. Seedling were grown from 2 or 3 seeds sown, and the healthiest was only retained, while the rest were thinned out at the foliation stage. $NO_3$-N, $P_2O_5$, and organic matter content differed significantly between growth conditions in the plastic greenhouse and in conventional shade in the soil. Disease also tended to be higher in the conventional shade than in the plastic greenhouse. Plant height and stem length showed an increasing trend with increasing sowing density and number of seeds sown per hole. However, these measures noticeably decreased when thinning treatment was conducted. Growth of the subterranean part of ginseng was not markedly influenced by sowing density, the number of seeds sown per hole, or thinning treatment. Root weight, which is an important factor in yield, was significantly affected by the number of seeds sown and thinning treatment. Interestingly, root weight tended to be higher in the thinning treatment plot than the untreated control plot. Damping-off and root rot increased noticeably as the number of seeds sown increased. Disease also tended to be substantially higher in the thinning treatment plot than the untreated control. However, physiological disorder of the plants did not vary with sowing density, the number of seeds sown, or thinning treatment.

• Journal of Ecology and Environment
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• 제32권3호
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• pp.159-165
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• 2009

The purpose of this study was to investigate the effects of thinning on fine root biomass and vertical distribution. and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, Kangwon Province. Fine root (< 2 mm in diameter) biomass ($367\;g/m^2$) in the site 'OC_75', thinning once in 1975, was 68% of those in the site 'CON', no thinning after planting, and in the site 'TC_00', thinning twice in 1975 and 2000. There were no significant differences of dead roots among treatments. Diameter $0{\sim}1\;mm$ roots were vertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 ($5.2\;Mg\;ha^{-1}\;yr^{-1}$) and TC_00 ($4.7\;Mg\;ha^{-1}\;yr^{-1}$), but the composition of litterfall was different: The proportion of leaves and branches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensis density by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots production by neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowground as well as aboveground responses, including both over- and understory vegetation, should be considered to measure the responses of trees in thinned forest ecosystems.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.463-470
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• 2017

The objectives of this study are to obtain the basic knowledge of anatomical characteristics and wood properties of thinning trees of young teak (Tectona grandis L.F.) for fulfill the timber demand in Indonesia. Nine thinning trees of 5-year-old teak clone trees were used for analyzing the cell morphology and air-dry density. Vessel diameters in pore and outer pore zones were 165 and $90{\mu}m$, respectively. Mean value of fiber diameter, cell wall thickness, and fiber length in outer pore zone were $14.6{\mu}m$, $2.07{\mu}m$, and 1.04 mm, respectively. In addition, mean value of air-dry density was $0.55g/cm^3$. The measurement and values of vessel diameter, fiber diameter, cell wall thickness, fiber length and air-dry density in the experimental had lower than those in the older teak. Therefore, it could be suggested that the wood from thinning young teaks was not appropriate as construction material, but it could be used for furniture which do not need high of strength properties. Furthermore, since the measurements values of anatomical characteristics were still increasing from pith to bark, it could be suggested that 5-year-old teak clones are still in a juvenile phase. Positively significant correlations were found between air-dry density and cell wall thickness, indicating that cell wall thickness is strongly correlated with wood density of teak.

• 한국환경농학회지
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• 제42권2호
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• pp.104-111
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• 2023

As apple trees mature, it is important to maintain good light distribution within the canopy to produce marketable fruits. Tree thinning is the selective removal of a proportion of trees growing in the orchard to provide more growing space and a good light environment for the remaining trees. This study was conducted over 3 years (14-16 years after planting) to investigate the influence of tree thinning on vegetative growth, yield, fruit quality, and blooming in the 14 years old slender spindle 'Fuji'/M.9 apple trees planted with the tree space of 3.2×1.2 m. The trees were placed in a control group (no thinning; 260 trees per 10 a) or a tree thinning group (thinned 50% of the control; 130 trees per 10 a). The tree thinning successfully improved light penetration, yield per tree, fruit red color, and yield efficiency for 3 years, and the tree thinning controlled the occurrence of biennial bearing. However, tree thinning significantly decreased accumulated yield per 10 a compared with the control. The vegetative growth, yield per tree, soluble solid contents, and blooming were not clear by the occurrence of biennial bearing in the control. These results indicated that tree thinning was a good method for improving light penetration and preventing biennial bearing in the old 'Fuji'/M.9 high-density apple orchards.

• 인간식물환경학회지
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• 제22권5호
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• pp.481-488
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• 2019

The purpose of this study is to suggest how to manage healing forests. Field investigation and surveys were conducted to produce results and 313 questionnaires collected from workers in the forestry sector and ordinary people were analyzed. The results were as follows: it is required to preserve flowering plants, scenic trees, and ecological trees in the understory vegetation, and to remove trees that block the forest landscape, leaving about 50 to 60 percent of the understory vegetation. The preferred density order of broadleaf trees was analyzed as follows: Betula platyphylla > Liriodendron tulipifera > Quercus acutissima. The preferred density order of coniferous trees was analyzed as follows: Abies holophylla > Cryptomerias japonica and Chameacyparis obtusa > Larix kaempferi > Pinus densiflora > Pinus koraiensis. The preferred density in healing forests was 81-89% compared to the number of residual trees for quantitative thinning. Specifically, the preferred density were 87% for P. koraiensis, 86% for L. kaempferi, 81% for P. densiflora, 83% for C. japonica, 84% for C. obtusa and 89% for Q. acutissima. In the case of healing forests, it is recommended to periodically conduct a small-scale thinning with different densities according to the species and diameter of trees based on the results of this study.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.321-324
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• 2008

Forest fire danger rate of thinning area was lower than that of non thinning area, because height rate of leewardside in burned stem of tree, damage rate of crown and mortality of tree in thinning area were 30.8%, 37% and 48.4% lower than that in non-thinning area, respectively. Intensity of forest fire varied depending upon topographical condition up slope, down slope, aspect, location as well as species, breast height diameter and forest tree density. Especially, a mountaintop area was burned down when forest fire was spread to up slope ridge of mountain.

• 한국산림과학회지
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• 제113권1호
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• pp.131-142
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• 2024

본 연구는 편백림의 생산목표 달성을 위한 생육단계별 적정 임분밀도관리 기준을 추정하고, 이로부터 솎아베기 적정 시업체계를 개발하는데 그 목적을 두고 있다. 모집된 편백림 216개 표본점을 대상으로 임내 세장목 점유율과 임분밀도 간의 관계특성을 분석하여 임분밀도 관리기준 지표로서 제시된 상대수확량지수는 Ry 0.75로 나타났다. 이로부터 기존 편백 시업체계의 생산목표별 타당성 검정을 실시한 결과, 임령 증가에 따른 솎아베기 강도의 불균형과 지위에 따른 생장속도가 반영되지 못하는 문제점이 있었다. 본 연구를 통해 작성된 생산목표별 솎아베기 시업체계에서, 대경재는 ha당 353본, 498.1 m³・ha-¹ 수확 가능하였으며, 중경재는 703본・ha-¹, 376.2 m³・ha-¹, 소경재는 1,758본・ha-¹, 249.5 m³・ha-¹으로 나타났다. 이상의 결과로부터 작성된 시업체계는 다양한 경영 목표에 따라 일률적으로 적용할 수는 없으나, 우리나라 편백림의 생장특성을 반영한 임분밀도관리도로부터 획득된 결과로서 실증적 참조 기준을 제시하는데 본 연구의 의의가 있다.

• 임산에너지
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• 제20권2호
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• pp.46-57
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• 2001

이 연구는 강송, 리기다소나무, 낙엽송 인공조림지를 대상으로 간벌 시업후 잔존임분밀도에 따른 임목생장 비교를 퉁해 침엽수 인공림을 적절히 관리하기 위한 보육 정보를 제공하고자 수행되었다. 연구결과를 요약하면 다음과 같다. 1. 잔존임분밀도별 임목의 직경생장은 강송림과 리기다소나무림, 낙엽송림 (가), (나)소반의 경우, 임분밀도가 감소할수록 직경생장이 증가하는 것으로 파악되었으며, 잔존임분밀도에 따른 임목의 생장은 통계적으로 유의적인 차이가 있는 것으로 분석되었다. 2. 잔존임분밀도별 임목의 수고생장 양상에서는 처리구별로 수고생장이 다소 차이가 있는 것으로 나타났으나 간벌의 직접적인 영향보다는 입지조건과 같은 환경요소의 차이에 의한 것으로 나타났다. 3. 각 임분밀도 조절 처리구별로 평균에 해당되는 직경급의 목편을 추출하여 최근 6개년간의 직경생장량을 실측한 결과는 전구간에서 직경급이 클수록, 잔존임분밀도가 낮을수록 직경생장량이 큰 것으로 파악되었다.

• 환경생물
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• 제41권4호
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• pp.447-454
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• 2023

본 연구는 편백림에서 임분밀도 조절이 산불 연료량에 미치는 효과를 분석하고자 수행하였다. 본 연구의 대상지는 전북 고창군 문수산에 위치해 있으며, 대조구, 30% 간벌처리구(light thinning, LT), 50% 간벌처리구(heavy thinning, HT)로 이루어져 있다. 1976년에 3년생 묘목을 3,000본 ha^-1 기준으로 식재하였으며, 2000년에 간벌을 실시하였다. 산불연료 생산량은 지면으로부터 1.2 m 높이의 원형 littertrap을 시험구별 3개씩 설치하여 2019년 4월부터 2020년 12월까지 2개월 간격으로 낙엽낙지량을 측정하였다. 산불연료 분해량을 알아보기 위해서 낙엽과 낙지를 5 g씩 넣은 낙엽망을 제작하여 유기물층에 묻은 후 18개월 후에 수거하여 분해상수를 구하였다. 산불연료 축적량은 정방향틀(0.09 m²)을 이용하여 2018년 9월에 시험구별 3반복으로 채취한 유기물의 건중량을 측정하였다. 산불연료 생산량은 LT와 HT 처리구 모두 대조구보다 통계적으로 유의한 수준으로 감소하였다(P<0.001). HT의 잎 분해상수는 대조구보다 유의하게 낮게 나타났다(P<0.05). LT의 산불연료 축적량은 대조구와 유의한 차이를 보이지 않았지만, HT의 산불연료 축적량은 대조구보다 유의하게 낮았다(P<0.01). 본 연구의 결과를 종합적으로 살펴보면 산불연료량은 간벌에 의해 감소하였다. 따라서 간벌을 통한 산림관리를 통해 연소물질이 감소되면 산불의 강도가 억제되어 산불을 빨리 진압해 대형산불의 저감효과를 기대할 수 있다.