• The Korean Journal of Ecology
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• 제15권4호
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• pp.395-410
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• 1992

Disturbance regime and tree regeneration were studied in kwangnung natural forest, an old-growth deciduous hardwood forest located in central korea. This forest is dominated by carpinus laxiflora, c.erosa, and quercus species. The area occupied by canopy gaps was 4.6% of the total forested area, and the mean size of canopy gaps was 92 $m^2$ with the maximum being 524 $m^2$. More than half of the gaps were less than four years old, and 3/4 of the gaps were created by death of only or two canopy trees, indicating the dominance of small-sized gaps in kwangnung forest. about half of the gap-makers were c. laxiflora, and another one third were quercus species. In contrast, the most frequent relacers were c. laxiflora while quercus species filled only 5% of the gaps, suggesting a future shift in tree species composition under the current disturbance regime. tree regeration was more conspicuous even in small gaps than non-gaps regardless of shade-tolerance of tree species, indicating the importance of gaps in tree regeneration.

• Journal of Ecology and Environment
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• 제30권4호
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• pp.325-330
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• 2007

Recognizing the ecological importance of forest gap formation for forest community structure, we examined the differences in species diversity between forest gaps and closed canopy areas for trees and shrubs in three developmental stages (seedling, sapling I, and sapling II) in a typical mixed broadleaved-Korean pine forest. We randomly placed 100 sample plots ($2{\times}2m$ for seedling and sapling I, and $5{\times}5m$ for sapling II) in forest gap and closed canopy areas of a 9 ha permanent sample plot for vegetation surveys of plants of each developmental stage in each habitat type. Even though the formation of forest gaps encouraged the occurrence of gap-dependent species and increased overall species diversity, there were no significant differences in species richness among the three developmental stages for both tree and shrub species (p>0.05). Comparing the two types of sites, statistical tests revealed no difference in species richness for trees, but highly significant differences (p<0.01) between forest types for shrubs for seedlings and sapling I, but not sapling II. Analysis of variance test indicated that there were no significant differences in species diversity among the three developmental stages of tree species (p>0.05) for both Simpson and Shannon indices. The variance for shrub seedlings was significantly different between forest gaps and closed canopy areas, but not for sapling I and sapling II. The analysis showed that the species diversity in forest gaps was significantly different from that of closed canopy areas for seedling and sapling I (p<0.01), but not for sapling II (p>0.05).

• The Korean Journal of Ecology
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• 제18권1호
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• pp.189-201
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• 1995

In order to clarify regeneration processes and mechanisms of the disturbed Pinus densiflora forest, responses of Pinus densiflora to gap formed by disturbance were analysed by growth of saplings and mature and growth equations were obtained from branch growth of mature trees and height growth of saplings, and age distribution of saplings and young trees recruited within gap was analysed in relation to gap age. Height growth of saplings within gaps was accelerated after gap formation. Such abrupt increases of growth of saplings after the gap formation might be resulted in the difference of growth of saplings between gap and non-gap areas. In fact, height and diameter of saplings in the central part of gap were larger than those of saplings in marginal parts of gap and non-gap area. However, density of saplings was not different in both parts. In addition, growth of annual rings of mature trees bordering on gap also increased after gap formation. Branch growth of mature trees bodering on gap was 6.3 - 6.5 cm /year and the mean radius of gaps created by death of only one canopy tree was about 3 m. Therefore, for those gaps to be closed by branch growth it will take 46 years. Growth of saplings within gap showed exponential equation. Fifty years will be required for the saplings to enter the forest canopy by the exponential growth equation. Therefore, gap created by only one tree might be closed by branch growth of surrounding canopy trees in advance of being done by height growth of saplings. But gaps created by death of trees more than 2 will be closed by the growth of saplings. Among the regenerating saplings and young trees within gaps, individuals established in advance of gap formation were more than those established after the gap formation. From these results, it was assumed that the disturbed Pinus densiflora forests in these sites were regenerated by height growth of saplings recruited in advance of gap formation.

• Journal of Plant Biology
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• 제33권2호
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• pp.147-150
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• 1990

Different species with similar niches can coexist in the same community if disturbances prevent compeptitive exclusion of competitively inferior species. Disturbances which open up gaps are common in all kind of community. Even in virgin forests without any artificial disturbance, there exist a significant proportion of trees of early successional shade-in-tolerant species in addition to the dominant late successional shade-tolerant species. In forest ecosystems, most canopy tree species including shade-tolerant ones require one or more gaps in their life-time to reach the canopy. Because of these frequent disturbances, forests can be considered of dynamic mosaics of patches of different ages and with different species composition which are in certain stages of recovery from disturbances. Disturbances temporarily increase the availability of resources such as light, water and soil nutrient for other in dividuals through the death of one or more canopy trees.

• Journal of Ecology and Environment
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• 제44권2호
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• pp.90-97
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• 2020

Background: Natural forests are generally considered to be less prone to biological invasions than other modified ecosystems, particularly when canopy cover is high. Few decades of management of degraded forests by local communities in Nepal has increased canopy cover and altered disturbance regimes. These changes might have reduced the abundance of invasive alien plant species (IAPS) in forests. To understand the status of IAPS in such forests, we studied two community managed Shorea robusta forests (Sundari and Dhusheri) of Nawalpur district in central Nepal. In these two forests, vegetation sampling was done using circular plots 10 m radius at forest edge, gaps, and within canopy. Variation of IAPS richness and cover across these microhabitats were compared, and their variation with tree canopy cover and basal area analyzed. Result: Altogether 14 IAPS were recorded in the study forests; among them Chromolaena odorata, Ageratum houstonianum, and Lantana camara had the highest frequency. Mikania micrantha was at the early stage of colonization in Sundari Community Forest (CF) but absent in Dhuseri CF. Both IAPS cover and richness was higher at forest edge and gap than in canopy plots and both these attributes declined with increasing canopy cover and tree basal area. Conclusion: The results indicate that increase in canopy cover and closure of forest gaps through participatory management of degraded forests can prevent plant invasions and suppress the growth of previously established IAPS in Shorea robusta forests of Nepal. This is the unacknowledged benefit of participatory forest management in Nepal.

• Journal of Ecology and Environment
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• 제32권2호
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• pp.87-96
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• 2009

Pinus thunbergii plantations in Pohang-si, Gyeongsangbuk-do, Korea, are of low ecological quality, with arrested succession and a high proportion of ruderal species. To improve the quality of the habitat, we created canopy gaps ($\sim42\;m^2$) and monitored changes in abiotic (light availability, canopy openness) and biotic (survival and growth of seedlings and understory communities) variables in 2007 and 2008 in plots that had received one of five types of treatment: cutting of canopy trees and removal of the understory (CU), cutting of canopy trees only (C), girdling of canopy trees and removal of the understory (GU), girdling of canopy trees (G) or control. Each treatment was applied to three replicate plots. Abiotic variables did not significantly differ among treatments. Survival rates of target species were slightly lower in the CU, G and control conditions. Based on logistic regression analysis, the only significant growth factor affecting survival was height growth. Positive effects of seedling height and leaf area growth on survival were also detected, but did not reach statistical significance. In treatment G, gradual improvement of overstory conditions and mitigation of competition by limitation of disturbance to the understory community were likely to have promoted seedling growth. There were no significant effects of gap treatments on changes in species abundance (cover and richness) and composition of understory between the study years. This result implies that the small gaps created in our study may be below the threshold size to affect understory growth. However, the results of this study are based on a short-term investigation of only two years. Long-term research is strongly recommended to clarify the effects of gap treatment on plant communities in afforested areas.

• Journal of Ecology and Environment
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• 제34권2호
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• pp.157-165
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• 2011

This study was conducted to determine the characteristics of gaps and natural regeneration of trees on Mt. Makiling, the Philippines. Canopy gaps in or around two 1-ha permanent plots and on 3-km line transects were investigated. Most of the gaps studied were formed or affected by Typhoon Milenyo, which hit the study site in September 2006. The most frequent mode of gap maker death was snap-off, whereas uprooting was relatively less important. The most frequent gap maker was balobo (Diplodiscus paniculatus) followed by magabuyo (Celtis luzonica) and katmon (Dillenia philippinensis). In contrast, the most frequent gap filler was magabuyo (C. luzonica). At the sapling layer, the most important species was magabuyo (C. luzonica), but there was a high proportion of lianas and palms. Most of the gaps had leaf area index (LAI) values between 3 and 5. A clear trend of a decrease in gap size and an increase in LAI was observed for 2 years from 2007 to 2009. New seedlings emerged very abundantly during the same time period. The rapid changes in the gaps were partially due to the excellent capability of tropical trees to resprout after the crown or stem was damaged by the typhoon. This study on gap dynamics may contribute to a better understanding of the natural regeneration process of trees in tropical rainforests.

• 한국산림과학회지
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• 제89권4호
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• pp.502-512
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• 2000

컴퓨터 시뮬레이션을 통하여 미국 북부 이차 활엽수림지역의 2개 임분을 대상으로 노숙림 발달과정을 평가하였다. 한 임분(phelps)은 77년생 임목들이 대부분 차지하고 있는 동령임분이고, 다른 임분(Wildcat Creek)은 노숙림의 구조적 특정을 다소 갖고 있는 연령이 많은 임목들이 있는 이령임분이다. 각 임분은 노숙림 자연발달 과정을 평가하기 위하여 임분구조, 직경분포, 고사목의 크기분포, 임분의 숨틈(Gap)크기, 3차원 임분공간도 및 수관투영도와 같은 구조적 특정을 이용하여 실시하였다. 본 시뮬레이션에 의하면, Phelps 임분은 현재를 기준으로 74년 후에, Wildcat Creek 임분은 13년 후에 노숙림 초기단계에 각각 도달하였다. 45년 시뮬레이션 동안 두 임분의 흉고직경분포는 직경크기가 커짐에 따라 모두 넓고, 평평한 형태를 나타냈으며, 고사목 크기분포에서는 두 임분 모두 직경크기가 커짐에 따라 고사목 수가 감소하는 경향을 나타냈다. Phelps의 숲틈 크기는 시뮬레이션 초기 연도보다 45년 후에 작게 나타난 반면, Wildcat Creek의 숲틈은 시뮬레이션 동안 일정한 패턴을 보였고, 큰 나무들의 고사로 인하여 큰 숲틈이 형성되었다.

• 한국산림과학회지
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• 제89권5호
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• pp.543-551
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• 2000

소나무의 갱신 특성을 구명하기 위하여 강원도 평창군 중왕산 지역 소나무 천연림에서 교란에 의해 형성된 숲틈을 대상으로 line-transect 조사법에 의해 소나무의 수관 architecture 특성을 조사, 분석하였다. 갱신 초기단계에 소나무는 숲틈에서 생장환경에 적응능력을 나타내었고 소개된 임분에서 자라는 소나무에 비해 architecture 특성은 다르게 나타났다. 소나무 천연림내 숲틈에서 소나무의 주 가지의 분지각의 변이폭은 작았고 주 가지의 길이 생장량은 가지 연령이 4~5년생 일 때까지 비교적 크게 나다났고 그 이후에는 점차 작아졌다. 숲틈에서 소나무의 줄기로부터는 주 가지가 평균 5개씩 발생하였고 주가지에서는 잔가지가 평균 4개씩 발생하였다. 줄기에서 발생한 주 가지는 방위별로 균일한 분포양상을 나타내었지만 주가지에서 발생하는 잔가지의 수는 숲틈의 크기가 $100{\sim}120m^2$이하일 때 주로 $S44^{\circ}E{\sim}S90^{\circ}W$ 사이의 방위에 많이 분포하였다.

• 한국환경생태학회지
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• 제17권2호
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• pp.144-152
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• 2003

본 연구는 독일 졸링(selling)지역의 산성화된 너도밤나무 임분에 군상벌채(group cutting. 지름 약 30m)를 통한 임관틈새를 조성하여 고회석분말 시비를 수행하고, 이러한 미세 입지환경적 요소의 변화와 너도밤나무 갱신치수의 발달과 성장 그리고 지피식생 및 근균의 동태를 파악하고, 이를 토대로 합리적인 천연갱신 방법과 건실한 산림생태계관리지침의 기초자료를 제공할 목적으로 수행되었다 본 연구의 주요 결과는 다음과 같다. 첫째 산성화가 심화된 너도밤나무(Fagus sylvatica) 임분에서의 고회석분말시비는 토양의 화학성을 크게 개선시켰으며 지피식생의 현저한 발달을 가져왔다. 둘째, 산성화된 너도밤나무 임분에서의 갱신치수의 발달 및 성장은 매우 결핍하였고 특히 측근의 발달이 억제되었다. 셋째, 엽성분분석에서 시비구는 대조구에 비해 칼슘(Ca), 마그네슘(Mg)의 함량이 높게 나타난 반면에 망간(Mn)함량은 상대적으로 낮게 나타났으며, 칼륨(K)과 칼슘(Ca), 마그네슘(Mg)사이에 상호 길항작용이 확인되었다. 넷째, 너도밤나무 치수에서의 상대근균 빈도(RM)는 임관틈새 중앙부에 비해 남가장자리에서 월등히 높게 나타났고, 시비로 인해 Laccaria amethystina의 확장세가 뚜렷하게 나타났다. 이러한 결과에서 너도밤나무의 천연갱신 작업법으로 치수의 밀도 및 발달을 위해 산벌갱신작업법이 더 효과적일 것으로 판단되며, 대기오염으로 인하여 산성화가 심화되는 숲은 석회시비를 통해 건실한 산림생태계의 복원이 필요하다고 판단된다.