• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2016.09a
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• pp.161-166
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• 2016

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2016.09a
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• pp.167-170
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• 2016

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.485-491
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• 2015

This study was conducted to develop stem volume models for the volume estimation of Quercus glauca Thunb. in Jeju Island, Republic of Korea. Furthermore, this study validated the developed stem volume models using an independent dataset. A total of 167 trees were measured for their diameter at breast height (DBH), total height and stem volume using non-destructive sampling methods. Eighty percent of the dataset was used for the initial model development while the remaining 20% was used for model validation. The performance of the different models was evaluated using the following fit statistics: standard error of estimate (SEE), mean bias absolute mean deviation (AMD), coefficient of determination (R²), and root mean square error (RMSE). The AMD of the five models from the different DBH classes were determined using the validation dataset. Model 5 (V = aD^bH^c), which estimates volume using DBH and total height as predicting variables, had the best SEE (0.02745), AMD (0.01538), R² (0.97603) and RMSE (0.02746). Overall, volume models with two independent variables (DBH and total height) performed better than those with only one (DBH) based on the model evaluation and validation. The models developed in this study can provide forest managers with accurate estimations for the stem volumes of Quercus glauca in the subtropical forests of Jeju Island, Korea.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.30-30
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• 2021

빌레나무는 국내에서 제주도 서부 곶자왈 지역에서만 자생하는, 어두운 환경을 선호하며 개체수가 희소한 종이다. 본 연구는 광 환경이 빌레나무 묘목 생장에 미치는 영향을 파악하고자 수행되었다. 서귀포시 난대아열대산림연구소 내 양묘장에 차광막을 이용하여 35%, 55%, 75% 차광 처리구를 설치하였고 노지에 비차광 처리구를 비교구로 설정하였다. 2019년 7월에 삽목 증식시킨 빌레나무를 2020년 5월에 각 처리구에 이식하였다. 2021년 3월에 각 차광 처리구의 모든 묘목의 묘고, 잎의 수, 줄기 수를 측정하고 생육이 건전하고 평균적인 묘목을 각 9본씩 굴취하여 건중량을 측정하였다. 35%, 55%, 75% 차광 처리구별 평균 묘고(cm)는 각각 53.2, 51.3, 41.4, 평균 잎의 수(개)는 41.3, 42.1, 24.4, 평균 줄기 수(개)는 3.1, 2.7, 2.2로 나타났다. 평균 묘고, 잎의 수, 줄기 수는 35% 차광 처리구와 55% 차광 처리구에서 75% 차광 처리구보다 높은 경향을 보였다. 건중량 분석 결과, 35%, 55%, 75% 차광 처리구별로 평균 잎 건중량(g)은 각각 11.3, 9.5, 5.5, 평균 줄기 건중량(g)은 5.6, 5.3, 2.6, 평균 뿌리 건중량(g)은 4.5, 3.6, 2.6으로 차광률이 낮을수록 증가하였으며 모든 부위별 건중량은 처리에 따른 통계적 유의성을 보였다(p<0.05). 지상부 대비 지하부 비율은 75% 차광 처리구에서 0.35로 가장 높았으며 35%, 55% 차광 처리구에서 0.27, 0.26로 나타났다. 한편, 비차광처리구의 모든 묘목들은 2021년 1~2월경 지상부가 고사하였다. 본 연구결과, 빌레나무 묘목은 노지에서 생존률이 불량하고, 차광 처리 시 차광률 증가에 따라 생장에 부정적인 영향을 받는 것으로 판단된다. 빌레나무의 건전한 생육 및 유무성증식을 통한 보급 증대에 기여하기 위하여 향후 온도, 수분 등 여러 환경 인자를 조절하는 연구가 필요한 것으로 사료된다.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.275-285
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• 2020

Background: In Korea, Symplocos prunifolia Siebold. & Zucc. is only found on Jeju Island. Conservation of the species is difficult because little is known about its distribution and natural habitat. The lack of research and survey data on the characteristics of native vegetation and distribution of this species means that there is insufficient information to guide the management and conservation of this species and related vegetation. Therefore, this study aims to identify the distribution and vegetation associated with S. prunifolia. Results: As a result of field investigations, it was confirmed that the native S. prunifolia communities were distributed in 4 areas located on the southern side of Mt. Halla and within the evergreen broad-leaved forest zones. Furthermore, these evergreen broad-leaved forest zones are themselves located in the warm temperate zone which are distributed along the valley sides at elevations between 318 and 461 m. S. prunifolia was only found on the south side of Mt. Halla, and mainly on south-facing slopes; however, small communities were found to be growing on northwest-facing slopes. It has been confirmed that S. prunifolia trees are rare but an important constituent species in the evergreen broad-leaved forest of Jeju. The mean importance percentage of S. prunifolia community was 48.84 for Castanopsis sieboldii, 17.79 for Quercus acuta, and 12.12 for Pinus thunbergii; S. prunifolia was the ninth most important species (2.6). Conclusions: S. prunifolia can be found growing along the natural streams of Jeju, where there is little anthropogenic influence and where the streams have caused soil disturbance through natural processes of erosion and deposition of sediments. Currently, the native area of S. prunifolia is about 3300 ㎡, which contains a confirmed population of 180 individual plants. As a result of these low population sizes, it places it in the category of an extremely endangered plant in Korea. In some native sites, the canopy of evergreen broad-leaved forest formed, but the frequency and coverage of species were not high. Negative factors that contributed to the low distribution of this species were factors such as lacking in shade tolerance, low fruiting rates, small native areas, and special habitats as well as requiring adequate stream disturbance. Presently, due to changes in climate, it is unclear whether this species will see an increase in its population and habitat area or whether it will remain as an endangered species within Korea. What is clear, however, is that the preservation of the present native habitats and population is extremely important if the population is to be maintained and expanded. It is also meaningful in terms of the stable conservation of biodiversity in Korea. Therefore, based on the results of this study, it is judged that a systematic evaluation for the preservation and conservation of the habitat and vegetation management method of S. prunifolia should be conducted.

• Korean Journal of Plant Taxonomy
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• v.47 no.3
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• pp.196-198
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• 2017

Sciaphila secundiflora occurs on Jeju Island as a second species of the genus Sciaphila in Korea. This is an important finding in relation to the flora of Korea, as species of the genus Sciaphila are concentrated mainly in Indonesia and Malaysia. Few species are found on the mainland of Asia, in Japan, Taiwan, China (Hainan), tropical Africa, Australia, and on the Pacific islands. In this paper, the species S. secundiflora is described and illustrated as a new record from Korea. In addition, we suggest that the species of the genus Sciaphila should be protected with regard to its habitat characteristics and for its phytogeographic and climatic significance.

• Korean Journal of Plant Taxonomy
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• v.48 no.1
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• pp.100-108
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• 2018

This study presents a survey of bryophytes in a subtropical forest of Nabeup-ri, known as Geumsan Park, located at Aewol Gotjawal in the northwestern part of Jejudo Island, Korea. A total of 63 taxa belonging to Bryophyta (22 families 37 genera 44 species), Marchantiophyta (7 families 11 genera 18 species), and Anthocerotophyta (1 family 1 genus 1 species) were determined, and the liverwort index was 30.2%. The predominant life form was the mat form. The rates of bryophytes dominating in mesic to hygric sites were higher than the bryophytes mainly observed in xeric habitats. These values indicate that such forests are widespread in this study area. Moreover, the rock was the substrate type, which plays a major role in providing micro-habitats for bryophytes. We suggest that more detailed studies of the bryophyte flora should be conducted on a regional scale to provide basic data for selecting indicator species of Gotjawal and evergreen broad-leaved forests on Jejudo Island.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.462-469
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• 2021

Maesa japonica (Thunb.) Moritzi & Zoll. is a rare evergreen shrub that occurs in west Gotjawal, Jeju island, Korea. This study was conducted to investigate effects of an artificial shading on flowering and growth characteristics of M. japonica seedlings. The level of shading had been set to be 35%, 55% and 75% using shading net. The stage of flowering and flowering ratio, seedling height, the number of leaves and stems, leaf area were measured. Flowering timings were delayed by shading. The number of flowering seedlings per plot and inflorescences per seedling were the most in 55% shading level. Tendency of decreased seedling height with increased shading level was shown. The number of leaves and stems were the fewest values in 75% shading level. The increased biomass with decreased shading level was statistically significant. Aboveground and underground biomass were 2.1 and 1.7 times higher in shading 35% than in shading 75%, respectively. Meanwhile, all seedlings in non-shading plots were dead in winter. Such might be speculated as results of the light stress. As a result, we conclude that M. japonica vitally demands the shading for growth and the optimal shading levels for growth and flowering are 35% and 55%, respectively.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.635-644
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• 2016

Birds play a main role in the formation and change of forest structures as they are seed-dispersal agents. This study aims to identify birds consuming fruits and seeds of the tree and their associated fruits and seeds on Jeju Island in the context on the forest restoration in Korea. We conducted field surveys twice a month from 2013 to 2015 at nine study sites located across Jeju Island and collected available photographic and observation records. A total of 50 species of birds consuming fruits and seeds of the tree were identified and birds belonging to Bombycillidae, Pycnonotidae, Zosteropidae, Sturnidae and Fringillidae were confirmed as major birds consuming fruits and seeds of the tree. Gulping was the dominant type of feeding as well as crushing, but relationship between the size of a bird and the number of fruit and seed species used by the bird was not significant. We also documented that 118 fruit and seed species were consumed by birds and that shrubby fruits and seeds were more consumed by birds than those of other plant types. The relative consumption rate of fruits and seeds ranged from 0.02 to 0.44, but five species were the most important fruits and seeds for birds. Our finding suggest that avian frugivorous gulpers will benefit the seed dispersal, especially of five fruiting plants, providing useful baseline data for forest restoration and urban park design.

• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.319-326
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• 2024

We evaluated the impact of temperature and salinity on the germination of true mangrove Sonneratia caseolaris (L.) Engl. seeds to determine the optimal conditions for their growth. Seeds were collected from Nam Dinh Province, Vietnam. The seeds underwent temperature treatments (19℃, 24℃, 30℃, and 38℃) and salinity treatments (0‰, 10‰, 20‰, 25‰, 30‰, 35‰, and 40‰). The analysis of germination characteristics and radicle growth indicated that, under the 30℃ condition, the germination rate was 88%, and the radicle growth was 25.24 mm, showing significantly higher germination rates GR), mean germination time (MGT), and germination performance index (GPI) than under other temperature conditions (P<0.05). In the 10‰ salinity treatment group, both the germination rate (88%) and radicle growth (39 mm) were significantly higher (P<0.05). High temperatures and salinity were not suitable for seed germination, and they significantly affected seed germination and early growth.