• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.618-629
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• 2000

This study was carried out to investigate ecological niche of Quercus acuta communities in Bogildo-island from July to October, 1998. This island is occupied by a subtropical evergreen broad-leaved forests. The study on community ecology of Q. acuta, mostly dominant species of subtropical forests, is very important for successful forest management. Sampling areas were selected in 16 quadrats, dominated by Q. acuta to examine the vegetation characteristics(plant identification, D.B.H.) and environmental elements (microtopography, altitude, slope degree, aspect, illumination and soil physicochemical properties). On the basis of data from field surveys, importance values were calculated for the dominance of Q. acuta and volume growth was analyzed by tree ring widths. The results obtained were as follows ; 1. The lists of vascular plants in the investigations were identified as 54 families, 91 genera, 113 species, 9 varieties, 1 formae. It appeared that 45 kinds were evergreen, 6 kinds(Camellia japonica, Ligustrum japonicum, Eurya japonica, Smilax china, Trachelospermum asiaticum var. intermedium, Carex lanceolata) were commonly observed in all plots and 5 species(Cinnamomum japonicum, Ardisia japonica, Cymbidium goeringii, Dryopteris bissetiana, Viburnum erosum) were most highly observed in all plots(over 80%). 2. The dominating species per strata were, Quercus acuta, Castanopsis cuspidata sp. Quercus salicina, Pinus thunbergii, Prunus sargentii in tree layer, Camellia Japonica, Ligustrum japonicum, Quercus acuta, Eurya japonica, Castanopsis cuspidata sp. in subtree layer, Camellia japonica, Ligustrum japonicum, Smilax china, Cinnamomum japonicum, Viburnum erosum in shrub layer and Trachelospermum asiaticum var. intermedium, Ardisia japonica, Carex lanceolata, Camellia japonica(seedlings), Quercus acuta(seedlings) in herb layer, all in descending orders. 3. Quercus acuta could be suggested as shade intolerant tree, considering the distribution in southern, western, nothern and eastern slopes in the descending orders. 4. Mean relative illumination in the forest is 0.89 % and it is relatively low in brightness. 5. Sustainment of Quercus acuta community couldn't be confirmed by judging from their reverse J curve in even-aged forest, as shown in D.B.H. distribution analysis. 6. The result of annual ring width analysis(mean ; 2.44 mm) showed three stages, such as a gentle increasing(1~12 year ; 2.04 mm), a relatively steep increasing(13~22 year ; 2.95 mm) and decreasing or stagnating(23 year after ; 2.41 mm).

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.254-261
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• 1995

The nationwide weed survey was conducted in lowland rice fields over whole country of Korea in 1992 in order to determine a change of weed community and to identify a major dominant weed species and/or problem weed. Based on morphological characteristics of weeds, population ratio of broad leaf weed was 42.6%, grasses weed-9.0%, sedges-33.4% and others were 15.0%. Annual weed was 33.4% while perennial weed was 66.6% in terms of life cycle of weeds. Meanwhile, there was different weed occurrence as affected by planting method of the rice plant. In hand transplanted paddy fields predominant weed species was Sagittaria trifolia L., Monochoria vaginalis Presl., and Aneilema japonica Kunth. In machine transplanted rice fields of infant and young rice seedling Eleocharis kuroguwai Ohwi. and S. trifolia L. were more predominant. There was high occurrence of M. vaginalis, Echinochloa crus-galli L., and Leesia japonica Makino in water seeding while E. crus-galli and Cyperus serotinus Rottb. were predominant weed species in dry seeded rice. Monoculture of the rice plant would cause to high occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and Sagittaria pygmaea Miq and there was higher population of S. trifolia, S. pygmaea, M. vaginalis, E crus-galli, and E. kuroguwai in double cropping system based on rice culture. In particular, there was high different weed occurrence under different transplanting times. E. kuroguwai, S. trifolia, S. pygmaea, M. vaginalis, and C. serotinus were higher population at the transplanting of 25 May and S. trifolia, E crus-galli, C. serotinus, and M. vaginalis at 10 June and S. pygmaea, E. kuroguwai, M. vaginalis, S. trifolia, and E. crusgalli at 25 June in Korea, respectively. Autumn tillage in terms of tillage time would cause more predominant weed species such as S. trifolia, E. kuroguwai, M. vaginalis, and S. pygmaea while spring tillage was higher population of E. kuroguwai, S. trifolia, E. crusgalli, M. vaginalis, and S. pygmaea. In plain area of paddy field there was higher occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and S. pygmaea and in mid-mountainous area S. trifolia, E. kuroguwai, M. vaginalis, E. crus-galli, and Ludwigia prostrate Roxb. while in mountainous area S. trifolia, M. vaginalis, Potamogeton distinctus Ben., E. kuroguwai, and E. crus-galli were. In 1992 the most ten predominant weed species at the rice field of Korea based on summed dominant ratio(SDR) were E. kuroguwai > S. trifolia > E. crus-galli > M. vaginalis > S. pygmaea > C. serotinus > L. prostrate > P. distinctus > A. japonica > Scirpus juncoides Roxb.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.139-146
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• 1997

The experiment was conducted at Gyeongbuk Provincial Rural Development Administration in 1996 to obtain basic information on weed ecology and effective weed control in direct-seeded rice fields under different seeding types and seeding times. A large number of upland weeds such as Echinochloa crus-galli, Digitaria sanguinalis, Capsella bursa-pastoris and Stetaria viridis etc occurred at early growth stage, while Eleocharis kuroguwai, Aneilema keisak and Cyperus serotinus dominated at late stage in dry seeded rice field. In wet seeded rice field, the dominance of E. crus-galli was lower and the occurrence of M. vaginalis and A. keisak were higher than in dry seeded field. Amount of weed occurrence in dry seeded field was 1.8 to 2.4 times greater than in wet seeded field and it increased with delaying seeding time. Increasing rate of weed occurrence through whole life cycle was the highest at 20 days after seeding (DAS) to 40 DAS, regardless of seeding types and seeding times. Simpson index in wet seeded field was higher than in dry seeded field and it gradually increased as growing of dominant species. For F-value test, it was recognized as statistical significant in seeding types, seeding times and interaction of two factors.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.545-552
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• 2009

This study was conducted to provide basic information for development of habitat-based conservation strategies of biological diversity in agricultural ecosystem. The carabid beetle assemblages were examined at four kinds of habitats(levee, dike, forest patch remnants and streamside) from three differently stressed areas located in Paltan-myun, Hwaseong city, Korea: agricultural and forest area(site 1), industrial area(site 2), and residential area(site 3). Pitfall trap samplings were carried out 39 times from November 2000 to November 2002. Our study's findings were that the composition of carabid beetle fauna, dominance species, and pattern of carabid beetle assemblage were different among the habitats. The similarity index was highest between two levees in site 2 and 3, and lowest between hillock in site 2 and streamside in site 3, and that among habitats fragmented by road with high traffic was lower than that among any other habitat types. So, we could know that agricultural land use respectively do an important role in diversity conservation and networking. These findings will be used to establish the land use and management plans in the aspects of conservation of biodiversity.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.24-31
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• 2014

This study was conducted to clarify the seasonal and elevational pattern of herbivore's feeding pattern in a temperate deciduous forest. We investigated the herbivore's feeding activity for three years (2011~2013) at three survey sites in Mt. Jirisan National Park (Piagol, Siamjae, Nogodan). We selected target tree species based on the dominance across the sites (Quercus, Acer, Rhododendron and Carpinus) and scored herbivore's feeding activity every one or two weeks from April to June using leaf damage index. We found that the herbivory started early at the low elevation site (Piagol, ${\approx}300m$), and the highest feeding activity occurred at the mid elevation site (Siamjae, ${\approx}900m$). At the highest elevation site (Nogodan, ${\approx}1300m$), the herbivory started late, but the total feeding activity accumulated quickly. Compared to the breeding time of Varied tit, an insectivore bird, it was overlapped with the feeding activity period of herbivores, suggesting close interaction among plants, insects and birds in this deciduous forest. We suggested a need of long-term monitoring of this tri-trophic interaction since duration of herbivore activity can be changed followed by climate change.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.195-204
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• 1999

To improve nut production and timber quality in a plantation, crown shape controls were suggested for Korean white pines (Pinus koraiensis) under age class III through the analyses of the crown shape controls for seed orchard trees in several species, of crown status of controlled and uncontrolled trees in a Korean white pine seed orchard, and of growth characteristics of plantation trees under age class III. For nut production from the small trees less than 8 m, modified leader type can be applied by cutting the central leader and all branches below 1 m and keeping 4~5 nodes with 3~4 whorled branches a node locating 1 m apart. Trees with a 4~8 m long trunk below the first living branch are shaped into trees for nut and timber production, which have a 4~8 m long knotless stem and a modified leader type crown with 4~5 nodes with 3~4 whorled branches a node at a distance of 1 m. Trees, showing the first living branch at or above 9 m from the surface, are pruned severely for timber production and result in a central leader type containing two fifths of the initial crown. It is advisable to remove the leader and the branches when collecting cones or after/during October to take advantage of easy labor and little resin while cutting. After stem cut, branches showing apical dominance are to be cut to control height when necessary. The removal of the uppermost node may be needed to control the crown shape several years after the initial stem-cut.

• Korean Journal of Weed Science
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• v.9 no.1
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• pp.39-45
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• 1989

An experiment was conducted at the Yeongnam Crop Experiment Station for 4 years from 1985 to understand the effect of repeated use of same herbicide on weed growth. For this, the most common 6 herbicides, butachlor, bifenox, butachlor/pyrazolate, piperophos/dimethametryne, bentazon and propanil were used as single treatment or combination treatment. For non chemical plots, weed occurrence was rapidly increased with time in terms of number and weight. However no rice plot recorded the least increasing ratio. Similar trend was obtained at the herbicide plot even though the increasing ratio varied by herbicide properties. The least increasing ratio (1200 was recorded at the plot of butachlor/pyrazolate (5 days after transplanting, 5 DAT) followed by bentazon+propanil(25 DAT) while the greatest ratio (28%) was obtained from the plot of bifenox (5 DAT). In general, Scirpus hotarui, Eleocharis kuroguwai and Cyperus serotinus was gradually inereased with time by herbicide application, particularly at the butachlor/pyrazolate treatment. The community dominance and simpson index increased at the plot of bentazon and propanil due to increased of particular species while other herbicide plots exhibited reverse trend. Grain yield was curvilinearly decreased with weed weight for both times, 40 DAT and heading time eventhough the correlation coefficient of heading time was higher than 40 DAT.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.50-62
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• 1999

Sediment core samples recovered from the Korea Deep Ocean Study (KODOS)-97 area were divided into two or three units according to their distinct changes in sediment colors and chemical and physical properties. Analyses of radiolarian faunas in the sediments and $^{10}Be$ ratios in each unit were performed to reveal stratigraphic and paleoceanographic history of the study area. In the upper part of the sediments, Tertiary radiolarians were mixed at various proportions with Quaternary assemblages probably by reworking process of bottom current and benthic animals. Dissolution of radiolarians was severe in deeper depth and in the Unit III, only few of the fragments of corroded Tertiary radiolarians were detectable. The mid layer of the Unit I belonged to Collosphaera invaginata Zone, the time period of 0.21 Ma. The Unit II belonged to Collosphaera tuberosa Zone with the time period younger than 0.42 Ma which was observed above the Stylatractus universus Zone. The Unit III is assigned to Tertiary, which is younger than the Late Eocene. Composition analyses of radiolarian assemblage and $^{10}Be$ ratio data indicated hiatus periods of more than 3 My between late of Middle Miocene and Pliocene resulting from erosion and dissolution caused by Antarctic Bottom Water. Stratigraphic evidence from radiolaria was well correlated with $^{10}Be$ data. Sedimentation rate during Quaternary can be suggested as 0.15-0.5 mm per 1000 years. Dominance of warm-water radiolaria species and the results reflected minimum climatic changes of tropical conditions.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.187-198
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• 2011

The objective of this study is to analyze the flora and forest vegetation of trails with high visitor density at Molundae. Nine quadrats of $20{\times}20m$ were selected for the survey. The survey was conducted from April to October 2010. The obtained results are summarized as follows. Plot1, plot2, plot3, plot4, plot6, and plot7 were located at slopes of $5{\sim}20^{\circ}$, 17~40m above sea level, and were formed with the colony of Japanese black pine(Pinus thunbergii Parl) and Japanese black pine(Pinus thunbergii Parl)-white oak(Quercus aliena Blume). Tree layer had the height of 8~20m, and the coverage of 50~70%, while subtree layer had the height of 3-8m, and the coverage 30~80%. On the other hand, shrub layer had the height of 2~4m, and the coverage of 10~30%, and herb had the height of 0.2~1m and coverage 5~20%. Plot5, plot8, and plot9 were located at the summit areas of 57~78m above sea level, and $0^{\circ}$ slope. Japanese black pine(Pinus thunbergii Parl) formed a community there. Tree layer was 8~20m high, and covered 60~70%, of the area, and subtree layer was 6~8m high, and coverage 30~40%. Shrub layer had the height of 2~6m, and the coverage of 30%, while herb layer had the height 0.2~2m, and the coverage 20-80%. Succession does not occur in the surveyed areas which have high visitor density. Artificially planted sawtooth oak(Quercus acutissima) trees were found to disturb succession and formation of multi-layer vegetation, resulting in the ecologically unstable forest. Therefore, the researcher suggested the strategy of managing the vegetation in the conclusion. This study has the limit in that the plots selected for the survey reflected only part of various trails in the Molundae area. It is necessary to suggest the vegetation management plans by selecting more diverse trail areas in consideration of the visitor density and behaviors, and analyzing the changes in vegetation quantitatively in order to manage the vegetation in urban areas damaged by visitors more effectively.

• Korean journal of applied entomology
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• v.29 no.1
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• pp.31-42
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• 1990

Storage ecosystems of rough rice, brown rice and polished rice were analyzed form Feb. 1987 to Nov. 1988 to investigate structures and ecological successions in the arthropod communities as well as changes in energy of the systems. The changes in temperature of stored rice showed high degree dependence on the temperature of storage room with time lag of about four weeks. Moisture content of rough rice, brown rice and polished rice during the period were in the range of 12.7$\pm$0.4, 13.1$\pm$0.4 and 13.5$\pm$0.3%, respectively. The arthropod communities in rough rice, brown rice and polished rice were qualitatively and quantitatively different. In rough rice, dominant species changed from Leptinotus reticulatus Endlein to Liposcelisentomophilus Endlein, while in brown rice from Pyralis farinalis L. to Sitophilus oryze (L.), unidentified parasitic wasps, Anisopteromalus calandrae Howard and Tribolium castaneum Herbst and finally to S. oryzae. In polished rice, the arthropod community showed an ecological succession similar to that in brown rice except for a transient dominance of two psocidspecies. Thearthropod community in rough rice was rather simple and unstable in comparison with those in brown rice and polished rice. The 1000 kernel weight of brown rice decreased slightly during the period when the arthropods were active (summer season), while that of rough rice and polished rice remained at the similar level. However, the ash content per unit volume of brown rice as well as rough rice and polished rice showed no increase during the period.