• Journal of Korean Society of Forest Science
• /
• v.108 no.1
• /
• pp.1-9
• /
• 2019

This study was carried out to compare stand structure and dynamics in Abies koreana forest in Yeongsil area of Mt. Hallasan between 2011 and 2017 by analysing DBH distribution, tree vitality, importance value (IV) and species diversity through the national long-term ecological research project conducted by National Institute of Environmental Research. As a result of DBH distribution, A. koreana decreased in all DBH class except 20-25 cm and the number of individual decreased by 16.3 percent from 780 to 655. As a result of tree vitality of A. koreana, the number of standing alive (AS) decreased by 16.2 percent from 652 to 546, while that of standing dead (DS) increased by 15.8 percent from 106 to 126 and that of fallen dead (DF) increased by 193.7 percent from 16 to 47, respectively. Importance value of A. koreana decreased by 2.4 percent point from 45.9 % to 43.5 %. Species diversity increased by 0.006 from 0.513 to 0.519. The weakening of the A. koreana in the Yeongsil area of Mt. Hallasan could be considerably supported by many aspects such as DBH distribution, tree vitality and importance value. Therefore, Long-term ecological monitoring and continuously research in that area should be conducted to clarify the effects of ecosystem changes.

• Journal of Wetlands Research
• /
• v.24 no.4
• /
• pp.354-366
• /
• 2022

To analyze the distribution of plant communities growing in river wetlands and the relationship between biotic and abiotic environmental factors, plant communities and environmental factors were investigated in river wetlands in the Boseong River. The Boseong River Wetland, the research site, consists of Hwapyeong Wetland, Bangujeong Wetland, and Seokgok Wetland. From June to September 2022, a plant community survey was conducted from the perspective of physiognomical vegetation, and the coverage of the emerging species followed the Braun-Blanquet scale. Plant species and the coverage of each species were recorded in the quadrant for plant community survey, and the cover of the quadrant, the total number of species, and the number of exotic species were measured as biological factors. As abiotic factors, altitude, orientation, inclination, soil texture, litter layer depth, dominant species diameter at breast height, and topography were recorded. In a total of 50 square plots, the most common Salix koreensis and Phragmites japonicus communities were found, and the community with the highest Shannon species diversity index was Phragmites japonicus-Echinochloa caudata community. As a result of ordination analysis by DCCA, the most significant clusters were separated according to topographic factors such as leeve, leeve slope, upper floodplain, lower floodplain, upper waterside, middle waterside, lower waterside, river island and opem water. As rare plants that need to be preserved in river wetlands, Hydrocharis dubia and Penthorum chinense were found in lower waterside, and it was found that the management of the river in the reservoir is necessary in line with the topographical distribution of ecosystem-disrupting plants, such as Paspalum distichum var. indutum.

• Korean Journal of Plant Taxonomy
• /
• v.50 no.4
• /
• pp.377-384
• /
• 2020

Korean Sedum formosanum N. E. Br. (Ju-geog-nip-gaet-bi-reum in Korean) was first recorded in 1887, 133 years ago. Since then, the species has not been collected and its current state has remained unclear. However, these plants were collected in 2020 and the corresponding taxonomic entity and distribution status were revealed. It is known to be distributed only in the southern region of Japan, the northern islands of the Philippines, and in Taiwan, with Taiwan being the collection site of the type specimen. However, on the basis of the findings of the fourth national natural environment survey, it has recently been established that this plant also grows in the crevices of rocks along the seashores of the Korean islands of Hataedo Island and Sangtaedo Island, Sinan-gun, Jeollanam-do. S. formosanum inhabiting Korea is a large succulent biennial that can attain a height of up to 65 cm and differs from its congeneric species in having erect follicles during the fruiting period. Notably, among the Korean Sedum species, S. formosanum is most similar to S. tosaense, although it can be distinguished from this species with respect to its monomorphic leaves that have rounded apices, and it also bears separate flowering and sterile stems. In this paper, we present a description and photographs of the Korean S. formosanum, indicate the differences between this and related species, and provide a key to related taxa.

• Korean Journal of Environment and Ecology
• /
• v.35 no.6
• /
• pp.632-643
• /
• 2021

The objective of this study was to examine vegetation community structure and distribution of Fraxinus chiisanensis in Mt.Minjuji of Chungcheongbuk-do by setting up and surveying 8 plots (400 m² each). Mean Importance Value (MIV) of Fraxinus chiisanensis in 8 plots was 35.19% in average (ranging from 26.07~42.74%). Since it is the dominant species in all plots, it is expected to maintain the present vegetation structure. The analysis of the DBH (diameter at breast height) showed that the diameter of Fraxinus chiisanensis in Mt.Minjuji ranges from 2 to 43cm. The majority of Fraxinus chiisanensis is expected to maintain current state unless disturbance or rapid environmental change occurs. The Species Diversity (H') was 0.8498~1.0261, Evenness (J') was 0.8160~0.9256, Dominance Index (D) was 0.0789~0.1840, Maximum Diversity (H'max) was 1.0414~1.2041. The analysis of annual ring and radial growth showed that the average age of Fraxinus chiisanensis in Mt.Minjuji was 29.1years(ranging from 22~58years). The average annual radial growth of Fraxinus chiisanensis was the highest in community G with 5.84mm and the lowest in community B with 2.80mm. The similarity index analysis revealed that the similarity index between community B and E, C and F, H was the highest with 69.0%, and the similarity index between community E and F was the lowest with 29.6%. Both the area of Fraxinus chiisanensis community of Mt.Minjuji and its population size are very small. Therefore, this area needs to be designated as Forest Genetic Resource Reserve.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.24 no.2
• /
• pp.83-94
• /
• 2022

In order to actively prepare to frost damage that occurs in the process of growing crops, the spatial and temporal distribution of frost occurrence in South Korea was derived using frost observation data from 20 regions over the past 21 years (2000~2020). The main products are the number of frost days, first frost day, and last frost day by region. And the climatic trends of these results were identified by performing the Mann-Kendall trend test and Sen's slope estimator. In South Korea, a lot of frost occurs in the inland area to the west of the Taebaek and Sobaek Mountains. Relatively closer to the coastal area, the number of frost days is small, the first frost day is slow, and the last frost day is early. The east coast region has fewer frost days, the first frost day is later, and the last frost day is earlier than the west coast region. The southern sea, the southeastern sea region, and the island region rarely experience frost. As a result of the annual time series trend analysis, although South Korea is a country where climate warming is progressing, there was no trend in reducing the number of frost days and slowing the first frost day, and it was found that the last frost day is delayed by 0.5 days per year.

• Horticultural Science & Technology
• /
• v.30 no.6
• /
• pp.694-699
• /
• 2012

To examine the EC model in a culture medium, basic culture medium of Rush (2005) and EC model of Robinson and Strokes (1959) were applied analyzing the equivalence ion total amount, the EC variable of cation and anion. Following the experiential translation by Steiner (1980), 130 optimized domestic and foreign culture media for crop growth were utilized, and estimated EC model was also demonstrated. Results from basic culture medium of Rush (2005) suggests an estimated EC by equivalence ion total amount and high reliable regressive model with 0.96 y = 1.33x - 0.23 of 0.96 as value $R^2$. It was found out that the change in concentration of positive ion and anion did not differ significantly with the increase and decrease of EC, however, there occurred a slight variable range. The change brings about a bigger anion influence than the previously reported positive ion, seemingly like those based on nitride ion and sulfur ion. The above EC estimated models confirmed that with optimized 130 domestic and foreign culture media for crop growth, the value derived will be as follows: $R^2$ = 0.98 with y = 1.23x - 0.02. In addition, the contour analysis of positive ion and anion for EC, with popularly known concentration range of EC $1.5-2.5dS{\cdot}m^{-1}$ reveals an equivalent of more than $11meq{\cdot}L^{-1}$ for positive ion and $15meq{\cdot}L^{-1}$ for anion. On the other hand, the left bottom, low concentration $1.5dS{\cdot}m^{-1}$ and the right above, high concentration $2.5dS{\cdot}m^{-1}$, for both positive ion and anion existed differently in a proper culture medium concentration. This study adapted variables of both positive ion and anion of EC simultaneously, unlike in the previous culture medium by ion ratio in mutual ratio of Steiner (1980), and offers an EC model that can estimate levels or positive ion and anion in proper concentration, EC $1.5-2.5dS{\cdot}m^{-1}$, with distributed features of ions.

• Korean Journal of Medicinal Crop Science
• /
• v.1 no.2
• /
• pp.115-119
• /
• 1993

This study was carried out to determine optimum harvest time of in vitro multiplied tuber Pinellia ternata(Thunb.)Breit from 1990 to 1992. Tuber yield and its related traits were observed with four harvest times. Plant height was 7.2cm at 6 months and 19.3cm at 24 months after planting. The number of tubers per unit area was significantly increased with the passage of growing time after planting$(78\;tubers/m^2)$, those were increased by 2.3 times in 6 months, 5.6 times in 12 months, 13.3 times in 18 months and 20.0 times in 24 months. The tuber sizes(length, width and weight) were highly enlarged during 12 to 18 months after planting compared with before or after this time. There were smaller tubers and lower tuber yields with shorter growing period, while large tubers above 7.1mm and higher yields with longer growing. It was suggested that the optimum harvest time was 18 months after planting, before over wintering rather than next year of spring, 24months after planting.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.1
• /
• pp.7-15
• /
• 2012

Agronomic characteristics of 150 adzuki bean ($Vigna$ $angularis$ W.F. Wight) germplasm collected in Korea were investigated in order to establish basic data for the improvement of crop breeding. Growth types were classified as 3 types of indeterminate type, determinate type, and semideterminate type, of which indeterminate type was the highest percentage of 96.6%. Seed color were classified as 8 colors of which dark brown took 66.5% in 150 adzuki bean germplasm. Days from seeding to maturity showed the range from 89 to 142 days with 115 days in the average and the highest frequency proportion was 37.2% of the group from 131 to 140 days, and the next was 27.3% of the group from 121 to 130 days among 150 germplasm. Pod length showed the range from 5.9 to 10.1 cm with 7.8 cm in the average and the highest frequency distribution of it was the group from 7.1 to 8.0 cm with the proportion of 45.1% and the next was the group from 8.1 to 9.0 cm with the proportion of 32.2%. Number of pods per plant showed the range from 5.0 to 132.5 pods with 28.5 pods in the average and the highest frequency distribution of it was the group from 11.0 to 20.0 pods with the proportion of 30.8% and the next was the group from 21.0 to 30.0 pods with the proportion of 28.6%. Number of seeds per pod showed the range from 5.3 to 11.3 seeds with 8.2 seeds in the average and the highest frequency proportion of it was the group from 7.1 to 8.0 seeds, which occupied 32.2% among 150 germplasm. 89.3% of 150 germplasm showed the resistance to shattering of grains at harvest period. 100 grain weight showed the range from 5.7 to 23.0 g with 12.9 g in the average and the highest frequency proportion of it was the group from 9.01 to 13.0 g, which occupied 43.3% and the next was the group from 13.01 to 17.00 g with the proportion of 28.5% of 150 germplasm.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.26 no.2
• /
• pp.127-139
• /
• 2024

Climate change has increased extreme weather events likewise heatwaves, heavy rain, and drought. Unlike other natural disaster, drought is a slowly developing phenomenon and thus drought damage increases as the drought continues. Therefore, it is necessary to understand the characteristics and mechanism of drought occurrence. Agricultural drought occurs when the water supply needed by crops becomes insufficient due to lack of soil water. Therefore, soil water is used as a key variable affecting agricultural drought. In this study, we examined the spatio-temporal distribution and trends of drought across the Korean Peninsula by determining the soil available water content (SAWC) through a model that integrated soil, meteorological, and crop data. Moreover, an investigation into the correlation between meteorological variables and the SAWC was conducted to assess how meteorological characteristics influence the nature of drought occurrences. During the soybean cultivation period, the average SAWC was lowest in 2018 at 88.6% and highest in 2021 at 103.2%. Analysis of the spatial distribution of SAWC by growth stage revealed that the lowest SAWC occurred during the flowering stage (S3) in 2018, during the leaf extension stage (S2) in 2019, during the seedling stage (S1) in 2020, again during the flowering stage (S3) in 2021, and during the seedling stage (S1) in 2022. Based on the average SAWC across different growth stages, the frequency of upland drought was the highest at 22 times during the S3 in 2018. The lowest SAWC was primarily influenced by a significant negative correlation with rainfall and evapotranspiration, whereas the highest SAWC showed a significant positive correlation with rainfall and relative humidity, and a significant negative correlation with reference evapotranspiration.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.37 no.1
• /
• pp.19-27
• /
• 2017

The objective of this study was to determine the growth characteristics of cool (C1) and warm season grasses (C2) in pastures mixed with C1 and C2 at an altitude of 400 m in Jeju island to establishing pasture suitable for grazing horses and to evaluate the effect of pastures mixed with tall and short type grasses on the intake characteristics of horses. C1 used in this study was Kentucky bluegrass, redtop (short type grass) and tall type grasses were orchardgrass and tall fescue, respectively. Treatments of this study were consisted of four groups and the short type grass used in pastures mixed with C1 and C2 was mainly bermudagrass. Four treatment groups were follow as; Treatment 1 (bermudagrass + Kentucky bluegrass + redtop) 2) Treatment 2 (bermudagrass + tall fescue + orchardgrass) 3) Treatment 3 (Kentucky bluegrass + redtop) 4) Treatment 4 (tall fescue + orchardgrass). Bermudagrass was a little winter killing and inhibition of plant growth at an altitude of 400 m. Plant heights in pastures mixed with C1 and C2 were grown better than that in pastures mixed with C1. Especially, plant height in Treatment 4 was higher than other treatments. Dry matter yield was in the following order: Treatment 4> Treatment 3> Treatment 2> Treatment 1. Dry matter yield in pastures mixed with C1 increased as compared with pastures mixed with C1 and C2. Dry matter yield in Treatment 3 was higher than other treatments. In the first investigation regarding vegetation distribution, bermudagrass ratios among grasses in Treatment 1 and Treatment 2 were 11.7 and 13.3%, respectively. The growth of bermudagrass in winter was low due to the cold damage. However the growth of Kentucky bluegrass, redtop, tall fescue and orchardgrass was good. In the second investigation, bermudagrass ratios among grasses in Treatment 1 and Treatment 2 were 5.0 and 11.7%, respectively. Growth of forage in the second investigation was poor as compared to the first investigation. nutritive values(crude protein content, neutral detergent fiber content, acid detergent fiber content, digestibility) were good in pastures mixed with C1 Especially, nutritive values in pastures mixed with tall was higher than those of pastures mixed short grasses. P content among minerals in Treatment 1 was higher than other groups. However, the content of Ca, Mg and Mn were lower. The contents of Ca, K, Mg, Na, Cu, Zn and Fe in Treatment 2 were higher. However, the contents of K, Mg, Na, Cu, Zn and Fe in Treatment 3 were lower. Therefore, we suggest that cool season grasses with short grasses were sowed to establishing pasture suitable for grazing horses at an altitude of 400 m in Jeju island.