• 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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.1
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• pp.53-69
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• 2015

Plants and birds have symbiotic relationship as the birds eat the fruits and disperse its seeds from the different places. Because Brown-eared Bulbul eats various fruits, We investigated the fruits consumed by Brown-eared Bulbul and the distribution of these seeds. Surveys were conducted at several area throughout Jeju Island at least twice a month from 2013 to 2014. We identified the fruits consumed by Brown-eared Bulbul through observation, pictures and interviews from the local residents. Results showed that this species consumed fruits from 82 plant species, belonging to 38 plant families. Thirty nine percent(39%) of these plant species belong to the Rosaceae, Lauraceae, Moraceae, Aquifoliaceae and Vitaceae and 33 species were classified as warm-temperate and subtropical plant which is 40% of the total plant species consumed. Two feeding types, which were gulper type and pecking type were observed for the Brown-eared Bulbul. It was also observed that this species preferred eating fruits of gulping type compared to that of pecking type. The average size of the fruits consumed through gulping was $8.92{\pm}3.41mm$ while it was $45.25{\pm}26.67mm$ for the pecker type. This bird species also consumed more fruits with globular shape compared to those of fruits with ellipse shape. For the fruit color, red and black-colored fruits were more preferred than yellow-colored fruits by Brown-eared Bulbul. Eaten frequency varied from 0.04 to 0.58 and the 10 fruits species were eaten frequently by Brown-eared Bulbul. This study would provide information for the role of Brown-eared Bulbul in the ecosystem as a seed dispersal agent.

• Journal of the Korean Wood Science and Technology
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• v.49 no.5
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• pp.482-490
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• 2021

This research was conducted to analyze the sound absorption effect of air-dried leaves from two evergreen tree species found in Korea's warm-temperate and subtropical regions. As eco-friendly sound absorption materials, Dendropanax morbiferusa, and Fatsia japonica leaves were prepared in three specimen units sizes 0.5 × 0.5 cm², 1.0 × 1.0 cm², and 2.0 × 2.0 cm², and each of them was formed at a thickness of 1.00 cm, 1.75 cm, and 2.50 cm. The measured sound absorption coefficients (SAC) for 18 conditions were comparatively analyzed in this study. The SAC of both tree species was significantly improved by increasing the dried leaf layer thickness. These results showed a more consistent and distinct trend for both tree species under the condition of 0.5 cm² in dried leaf size compared to other leaf specimen sizes. However, as the thickness increased, the difference in sound absorption effect according to the leaf size tends to decrease overall. In the case of D. morbiferus, there was no significant difference in SAC based on leaf size under the condition of 2.5 cm thickness (p < 0.05). The highest mean SAC was found in a 2.5 cm thick condition with a leaf size of 0.5 × 0.5 cm², 0.549 for D. morbiferusa, and 0.594 for F. japonica, respectively.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.613-621
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• 2022

The study aim was to investigate changes in the diameter, number of standing trees, stand volume per ha and site index by the forest survey order, climate zone (northern temperate, central temperate, southern temperate, and warm temperate regions), and altitude in 100 m intervals) by collecting samples of Robinia pseudoacacia from the fifth, sixth, and seventh national forest survey datasets. The rotation cutting age, which is a standard used for wood, was calculated. The changes were statistically analyzed by performing ANOVA and the Duncan multiple test. Diameter growth naturally increased according to the forest survey order and was lowest in the southern temperate region by climate zone and lowest at the 301-400 m altitude. The number of standing trees per ha did not change according to the forest survey order and altitude, and the density was highest in the central temperate region and lowest in the southern temperate region. The stand volume per ha increased according to the forest survey order, and the climate zone was divided into two groups: ① northern temperate region and central temperate region, ② southern temperate region and warm temperate region. The stand volume growth was highest at the 201-300 m point. Thesite index showed results similar to the change pattern of the stand volume per ha. The growth curve, which can be seen by the change in stand volume per ha, was estimated by applying theWeibull formula, and the stand volume per ha was estimated to reach approximately 200 m³/ha at 50-60 years. The rotation of the highest production in volume, which is the standard for using trees as wood rather than honey sources, was calculated to be 34 years.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2009.04a
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• pp.93-96
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• 2009

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.136-139
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• 2003

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2002.04a
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• pp.89-91
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• 2002

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.631-640
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• 2020

In this study, the effect of specimen size and layer thickness on the sound absorption of the leaves of two evergreen broad-leaved tree species, Dendropanax morbiferus and Fatsia japonica, was investigated. The specimen sizes of 0.5 × 0.5, 1.0 × 1.0, and 2.0 × 2.0 ㎠ and layer thicknesses of 1.00, 1.75, and 2.50 cm were considered. At the layer thickness of 2.5 cm, the leaf of the D. morbiferus showed no significant difference in sound absorption coefficients (SACs) as the sample size varied, however, a significant change in SACs was recorded in that of the F. japonica. At 1.0-cm thickness, the SACs of the F. japonica leaf varied more remarkably with the sample size. The 2.50-cm-thick F. japonica leaf with the specimen size 0.5 × 0.5 ㎠ exhibited the highest sound absorption effect among all samples investigated.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.417-425
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• 2023

The aim of this study was to derive stem taper equations for Quercus acuta, one of main evergreen broad-leaved tree species found in warm temperate regions, and to prepare a stem volume table using those stem taper equations. A total of 688 individual trees were used in the analysis, which were collected from Jeonnam-do, Gyeongnam-do, and Jeju-do. The stem taper models applied to derive the stem curve pattern were the Max and Burkhart, Kozak, and Lee models. Among the three stem taper models, the best explanation of the stem curve shape of Q. acuta was found to be given by the Kozak model, which showed a fitness index of 0.9583, bias of 0.0352, percentage of estimated standard error of 1.1439, and mean absolute deviation of 0.6751. Thus, the stem taper of Q. acuta was estimated using the Kozak model. Moreover,thestemvolumecalculationwasperforme d by applying the Smalian formula to the diameter and height of each stem interval. In addition, an analysis of variance (ANOVA) was conducted to compare the two existing Q. acuta stem volume tables (2007 and 2010) and the newly created stem volume table (2023). This analysis revealed that the stem volume table constructed in the Wando region in 2007 included about twice as much as the stem volume tables constructed in 2010 and 2023. The stem volume table (2023) developed in this study is not only based on the regional collection range and number of utilized trees but also on a sound scientific basis. Therefore, it can be used at the national level as an official stem volume table for Q. acuta.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.429-434
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• 2007

This study was conducted to estimate site productivity of Quercus acutissima and Quercus mongolica by four forest climatic zones. We used site environmental variables (28 geographical and pedological factors) and site index as a site productivity indicator from nation-wide 23,315 stands. Based on multiple regression analysis between site index and major environmental variables, the best-fit multivaliate models were made by each species and forest climatic zone. Most of site index prediction models by species were regressed with seven to eight factors, including altitude, relief, soil depth, and soil moisture etc. For those models, three evaluation statistics such as mean difference, standard deviation of difference, and standard error of difference were applied to the test data set for the validation of the results. According to the evaluation statistics, it was found that the models by climatic zones and species fitted well to the test data set with relatively low bias and variation. Also having above middle of site index range, total area of productive sites for the two Quercus spp. estimated by those models would be about 6% of total forest area. Northern temperate forest zone and central temperate forest zone had more productive area than southern temperate forest zone and warm temperate forest zone. As a result, it was concluded that the regressive prediction with site environmental variables by climatic zones and species had enough estimation capability of forest site productivity.