• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.43-52
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• 2021

In this study, carbon (C) and nitrogen (N) inputs by the litterfall of Japanese cypress (Chamaecyparis obtusa Endlicher) planted in pine wilt disease-disturbed forests were determined. The study sites were located in Sacheon-si, Gyeongsangnam-do. Eight plots under two regeneration sites (DR: four plots of C. obtusa planted under slightly disturbed Pinus thunbergii stands; CR: four plots of C. obtusa planted following the clear-cutting of severely disturbed pine stands) were established to collect litterfall from December 2018 to December 2019. The growth of diameter at breast height (DBH) was significantly higher in the CR treatment (12.10 cm) than that in the DR treatment (9.42 cm). C and N concentrations and the C/N ratio in C. obtusa leaf litter did not differ significantly between the two regeneration treatments, but the C/N ratio was significantly lower in the leaf litter collected in October (93) relative to that collected in December (143). The C concentration of litterfall components was significantly higher in C. obtusa leaf litter and in P. thunbergii needle litter than in broadleaved and miscellaneous litter, whereas the N concentration in broadleaved and miscellaneous litter was significantly higher than that in the leaf litter of C. obtusa and in branch litter. Thus, the C/N ratio was significantly higher in C. obtusa leaf litter and branch litter compared with that in miscellaneous and broadleaved litter. Respective C and N inputs by leaf litter were 773 kg C ha-1 yr-1 and 6.95 kg N ha-1 yr-1 for the CR treatments, and 78 kg C ha-1 yr-1 and 0.70 kg N ha-1 yr-1 for the DR treatment. Total C and N inputs were higher for the DR treatment (3,765 kg C ha-1 yr-1 and 47.6 kg N ha-1 yr-1, respectively) than for the CR treatment (1,290 kg C ha-1 yr-1 and 17.2 kg N ha-1 yr-1, respectively). These results indicate that, for C. obtusa, the DBH growth in the CR treatment was superior to that in the DR treatment, but the C and N inputs by litterfall were considerably reduced in CR treatments.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.579-593
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• 2021

In order to understand the types of vegetation in warm temperate-climate zones, vegetation was investigated in several island areas in Jeollanam-do (Jindo, Wando, Gangjin, Goheung, and Yeosu). The evaluation standard for degraded level of warm temperate forests were proposed based on the importance percentage (IP) in canopy layer of the evergreen broad-leaf forests and the number of arboreal evergreen broad-leaf species. Through these measurements, the restoration types and techniques for each degraded level were estimated, and it is intended to be used in establishing restoration plans for the southwest coast island area. The vegetation was analyzed using the two-way indicator species analysis (TWINSPAN) method using survey data of 307 plots. As a result, it was divided into 8 communities, and the appearance characteristics of evergreen broad-leaf species were identified in each community. Community I was located on the lower slope at an altitude of 86.6 m, and Neolitsea sericea and Castanopsis sieboldii were dominant. Communities II and III were the vegetation types that appear on the coast below an altitude of 10.5 to 22.5 m, and Machilus thunbergii, Cinnamomum japonicum, N. sericea, and C. sieboldii were dominant. Communities IV and V were vegetation types that appeared in the lower and middle slops between the altitudes of 71.9 to 153.4m, and C. sieboldii was dominant. In community VI, the N. sericea was dominant in the lower and middle slops at an altitude of 166.9 m. The last communities VII and VIII were the vegetation types that appeared on the middle slop at an altitude of 187.8 to 246.2 m. Also, Quercus acuta and Q. salicina were present. In summary, the evergreen broad-leaf forests dominated by M. thunbergii, C. japonicum, and N. sericea appeared mainly in the coastal areas of the lowlands. The community of C. sieboldii was distributed higher inland than this community. The communities that appeared mainly in the inland highlands at levels above these two communities were Q. acuta and Q. salicina. The degraded level was classified as 0 to V, according to the IP of arboreal evergreen broad-leaf species and the number of arboreal evergreen broad-leaf species. According to the degraded level, the restoration types (preservation, induction, improvement, creation) and the restoration techniques were determined.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.1-12
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• 2023

We analyzed the distribution area of debris slopes in Mudeungsan (Mt. Mudeung) National Park by comparing aerial photos of the past (1966) and the present (2017) and identified the vegetation characteristics that affect the change in the area of the debris slopes by investigating the vegetation status of the debris slopes and the surrounding areas. The area of debris slopes in Mt. Mudeung appears to have been reduced to a quarter of what it used to be. Debris slopes here have decreased at an average rate of 2.3 ha/yr over 51 years by vegetation covers. Notably, most of the small-area debris slopes in the low-inclination slopes disappeared due to active vegetation coverage. However, there are still west-facing, south-west-facing, south-facing, and large-area debris slopes remaining because the sun's radiant heat rapidly raises the surface temperature of rock blocks and dries moisture, making tree growth unfavorable. Because of these locational characteristics, the small-scale vegetation in the middle of Deoksan Stony Slope, which is the broadest area, showed distinct characteristics from the adjacent forest areas. Sunny places and tree species with excellent drying resistance were observed frequently in Deoksan Stony Slope. However, tree species with high hygropreference that grow well in valleys with good soil conditions also prevailed. In some of these places, the soil layer has been well developed due to the accumulation of fine materials and organic matter between the crevices of the rock blocks, which is likely to have provided favorable conditions for such tree species to settle and grow. At the top of Mt. Mudeung, on the other hand, the forest covered the debris slopes, where Mongolian oaks (Quercus mongolica) and royal azaleas (Rhododendron schlippenbachii), which typically grow in the highlands, prevailed. This area was considered favorable for the development of vegetation for the highlands because the density of rock blocks was lower than in Deoksan Stony Slope, and the soil was exposed. Moreover, ash trees (Fraxinus rhynchophylla) and Korean maple trees (Acer pseudosieboldianum) that commonly appear in the valley areas were dominant here. It is probably due to the increased moisture content in the soil, which resulted from creating a depressive landform with a concave shape that is easy to collect rainwater as rock blocks in some areas fell and piled up in the lower region. In conclusion, the area, density of the rock blocks, and distribution pattern of rock block slopes would have affected the vegetation development and species composition in the debris slope landform.

• Journal of Life Science
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• v.33 no.4
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• pp.357-362
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• 2023

This report looks at an agar-degrading marine bacterium and characterization of its agarase. Agar-degrading marine bacterium JS-1 was isolated with Marine agar 2216 media from seawater from the seashore of Sojuk-do, Changwon in Gyeongnam Province, Korea. The agar-degrading bacterium was named as Agarivorans sp. JS-1 by phylogenetic analysis based on 16S rRNA gene sequencing. The extracellular agarase was prepared from the culture media of Agarivorans sp. JS-1 and used for characterization. Relative activities at 20℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, and 60℃ were 70%, 74%, 78%, 83%, 87%, 100%, 74%, and 66%, respectively. Relative activities at pH 5, 6, 7, and 8 were 91%, 100%, 90%, and 89%, respectively. Its extracellular agarase showed maximum activity (207 units/l) at pH 6.0 and 50℃ in 20 mM Tris-HCl buffer. The residual activity after heat treatment at 20℃, 30℃, and 50℃ for 30 minutes was 90%, 70%, and 50% or more, respectively. After a 2-hour heat treatment at 20℃, 30℃, 35℃, 40℃, and 45℃, the residual activity was 80%, 68%, 65%, 63%, and 57%, respectively. At 50℃ and above, after heat treatment for 30 minutes, the residual activity was below 60%. Thin layer chromatography analysis suggested that Agarivorans sp. JS-1 produces extracellular β-agarases as they hydrolyze agarose to produce neoagarooligosaccharides such as neoagarohexaose (20.6%), neoagarotetraose (58.5%), and neoagarobiose (20.9%). Agarivorans sp. JS-1 and its thermotolerant β-agarase would be useful in the production of neoagarooligosaccharides, showing functional activity such as inhibition of bacterial growth and delay of starch degradation.

• Korean Journal of Environment and Ecology
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• v.37 no.2
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• pp.163-178
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• 2023

This study was conducted to understand the vegetation characteristics of Cheongwansan Provincial Park through the analysis of the plant community structure and to build data necessary for the continuous management and protection of Cheongwansan Provincial Park. The TWINSPAN and DCS analyses of the plant community structure of 63 survey districts in Cheongwansan Provincial Park identified eight colonies, including Cryptomeria japonica Community (I), Chamaecyparis obtusa-Pinus densiflora Commuity (II), P. rigida-P. densiflora Community (III), mixed coniferous and broad-leaved Community (IV), P. densiflora Community (V), deciduous broad-leaved such as Quercus spp. Community (VI), Q. mongolica-P. densiflora Community (VII) and P. thunbergii Community (VIII). The colonies can be grouped into afforestation communities (I, II, and III) dominated by C. obtusa, C. japonica, and P. rigida and natural forest communities (IV, V, VI, VII, and VIII) dominated by native species. Although Cheongwansan Provincial Park is a provincial park area that can represent natural ecosystems and landscapes, the rate of artificial forests is higher than that of other provincial parks. Most of the artificial forest communities are expected to maintain their current state, but since native species such as Machilus thunbergii, Neolitsea sericea, and deciduous broad-leaved, which are warm-temperate trees introduced through surrounding natural forests, appear in the lower layer, it is determined that it is possible to induce succession to natural forests suitable for climatic characteristics through management, and monitoring for continuous management is also necessary. Deciduous broad-leaved such as Quercus spp. Copete with P. densiflora in most natural forest communities. The vegetation series in the warm-temperate region of Korea appears to be in the early stages, and it is believed that the succession to Q. serrata or Q. mongolica, which appears next to coniferous in the series, is in progress. However, M. thunbergii and N. sericea, which appear in the middle stage of the succession in the warm-temperate region, have started to appear, and since Jangheung-gun belongs to the warm-temperate region considering the climate characteristics, the eventual succession to the warm-temperate forests dominated by evergreen broad-leaved is also expected. In this study, we built vegetation data from Cheongwansan Provincial Park, which lacks research on vegetation. However, since vegetation research in Cheongwansan Provincial Park is still insufficient, it is believed that further research should be continuously conducted to establish forest vegetation data and observe vegetation changes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.380-389
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• 2007

Stable carbon and nitrogen isotopes were analyzed in suspended particulate organic matter, macroalgae and macrobenthic invertebrates in order to determine the importance of primary organic matter sources in supporting food webs of rocky subtidal and intertidal macroalgal beds in the Korean coasts. Investigations were conducted at the inter tidal sites within Gwangyang bay, a semi-enclosed and eutrophicated bay, and the subtidal sites of the east coast, a relatively oligotrophic and open environment, in May and June 2005. Water-column suspension feeders showed more negative $\delta^{13}C$ values than those of the other feeding guilds, indicating trophic linkage with phytoplankton and thereby association with pelagic food chains. In contrast, animals of the other feeding guilds, including interface suspension feeders, herbivores, deposit feeders, omnivores and predators, displayed relatively less negative $\delta^{13}C$ values than those of the water-column suspension feeders and similar with that of macroalgae, indicating exclusive use of macroalgae-derived organic matter and association with benthic food chains. Most the macrobenthic species were considered to form strong trophic links with benthic food chains. In addition, the distribution of higher $\delta^{15}N$ values in macrobenthic consumers and macroalgae at the intertidal sites of Gwangyang Bay than those at the subtidal sites of the east coast suggests that anthropogenic nutrients may enhance the macroalgal production at the intertidal sites and in turn be incorporated into the particular littoral food web in Gwangyag Bay. These results confirm the dominant role of macroalgae in supporting rocky subtidal and intertidal food webs in the Korean coasts.

• Journal of the Korean Society of Radiology
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• v.84 no.5
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• pp.1094-1109
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• 2023

Purpose To investigate whether CT-based tumor regression grade (ctTRG) can be used to predict the response to neoadjuvant chemotherapy (NAC) in colon cancer. Materials and Methods A total of 53 patients were enrolled. Two radiologists independently assessed the ctTRG using the length, thickness, layer pattern, and luminal and extraluminal appearance of the tumor. Changes in tumor volume were also analyzed using the 3D Slicer software. We evaluated the association between pathologic TRG (pTRG) and ctTRG. Patients with Rödel's TRG of 2, 3, or 4 were classified as responders. In terms of predicting responder and pathologic complete remission (pCR), receiver operating characteristic was compared between ctTRG and tumor volume change. Results There was a moderate correlation between ctTRG and pTRG (ρ = -0.540, p < 0.001), and the interobserver agreement was substantial (weighted κ = 0.672). In the prediction of responder, there was no significant difference between ctTRG and volumetry (Az = 0.749, criterion: ctTRG ≤ 3 for ctTRG, Az = 0.794, criterion: ≤ -27.1% for volume, p = 0.53). Moreover, there was no significant difference between the two methods in predicting pCR (p = 0.447). Conclusion ctTRG might predict the response to NAC in colon cancer. The diagnostic performance of ctTRG was comparable to that of CT volumetry.

• Journal of Sericultural and Entomological Science
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• v.23 no.1
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• pp.1-31
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• 1981

Rootability of the hardwood cuttings of mulberry was related not only histological characteristics but dependent on biochemical properties. In this connection, the characteristics of the hardwood cuttings were histologically observed and the growth substances produced by the cuttings were also identified by means of mung bean bioassay. Amino acid, carbohydrate, nucleic acid contents, and the C/N ratio were also analysed. The results are summarized as follows. 1. There were differences in rootability of cuttings between mulberry species and varieties Among the three mulberry species tested, Morus Lhou Koidz. showed the highest rootability while M. bombycis showed the lowest one. In varietal differences in rootability, it was shown that the varieties could be grouped according to rootability: high varieties(above 80%), medium(41~79%), and low(below 40%). The higher varieties were Kemmochi, Nakamaki, Kosen, and Wusuba roso. 2. The histological characteristic of the hardwood cuttings most closely related to rootability was cell layer arrangement in the sclerenchyma tissue. The lower rootability varieties developed two or three overlapping cell layers in the bark tissue and in the higher rootability varieties they were scattered over the primary cortex. 3. In the higher rootability varieties, there was a positive correlation between the development of root primodia and rootability of the hardwood cuttings. It was also shown that there was a close relationship between the size of primodia and the surface area of the lenticel with rootability of the cuttings. 4. Effect of growth substances extracted from the hardwood cuttings were determined by mung bean bioassay. The higher rootability varieties usually showed higher activities of the growth substances, in contrast the lower rootability varieties showed higher activities of the inhibitory substances. 5. It was evident that the substance separated by paper chromatography was identified as indole acetic acid with $R_f$ value ranging from 0.3 to 0.5. The other substances detected at a $R_f$ value ranging from 0.8 to 1.0 and origin to 0.1 were also responsible for rooting. 6. There exists a quantitatively different distribution of growth substances in a synergistic system in the tissues of cuttings, and the balance between growth and inhibitory substances gives rise to the development of rooting. Particularly, no descent of the substances from winter buds resulted in no rooting of cuttings but these substances were produced a week after planting in a warm environment. 7. It was shown that there were positive correlations between carbohydrate ($r=0.72^*$) and total sugar ($r=0.67^*$) and rootability, respectively, but there were negative correlations between reducing sugars ($r=-0.75^*$) and rootability. 8. High C/N ratio gave rise to high rootability($r=0.67^*$). The latter therefore depended on high amount of carbohydrate rather than nitrogen in the cuttings. 9. The content of RNA and DNA in the cuttings was not changed for upto two weeks after the cuttings were planted. Then an increase in RNA content took place in only the high rootability varieties. 10. There were quantitative and qualitative differences in the compositions of the amino acids between the high rootability varieties and the low rootability varieties. More aspartic acid and cystine were found in the higher rootability varieties than in the low rootability varieties.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2191-2205
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• 1971

In this research, Nong-rim No. 6 was adopted as a test variety of rice. Rice seedlings were transplanted on June 14, 1970. Roots were settled into soil on June 20 and a total number of days irrigated of $21cm{\times}21cm$ and an area of $9.9m^2$ for a test plot were accepted, planting 70 stumps of rice in a test plot. The soil in test plots are classified by soil test as oam, and its chemical contents are as shown in Table 3. Irrigation water was secured by pumping from the Sudun stream that originates at the Suho reservoir. Accordingly, the qualities of irrigation. water are considered to be the same as those of water stored in the Suho reservoir. There were 54 days of intermittent rainfalls in total during the whole 110-day period of irrigation. As a result, it is likely that the growth of rice plants was influenced by rainfall at a comparatively great degree. In order to measure the amounts of water consumption, infiltrometers, measuring devices for the decreases of water depths and lycimeters were provided. As a result of measurements, an average daily rate of infiltration was observed to be 14mm/day. It is expected from this research that the effect of increased yield will be secured by supplying optimum amounts of water for irrigation on proper times, and that the amounts of water consumption for irrigation can be saved by applying suitable irrigation methods. The test results obtained are summarized as follows: 1. Yields produced in the test plots of continuous irrigation are lower than those in the test plots of rotational irrigation, i.e., yields produced at the test plots irrigatied once in a period of 8 days are higher by 27% in average than those produced at test plots of continuous irrigation. 2. The amounts of irrigation water for test plots, which have a clay layer of 9cm in thickness and vynil diaphragm without holes, are saved by about 52% in comparison with ordinary test plots. 3. Ears are sprouted 5 days earlier at continuous irrigation plots as compared with other test plots. 4. It seems that there are growing stages of rice plants such as those of forming and sprouting of ears, in which the amounts of irrigation water are consumed more in comparison with the other stages. Therefore, it may be possible to increase of decrease the amount of irrigation water, according to the growing stage of rice plant, so as to save irrigation water.

• Journal of the Korean Wood Science and Technology
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• v.13 no.1
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• pp.3-18
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• 1985

In Korea, a study on the anatomical features of pitch pine (pinus rigida Miller) branch wood through photo-microscopical method was reported in 1972 by Lee. Therefore, as a further study of Lee's on the anatomical features in branch wood of pinus rigida miller that grows in Korea, compression wood, opposite wood, and side wood were selected and treated for the purpose of comparing their structures revealed on cross and radial surface through scanning electron microscope in this study. The obtained results in this study were summarized as follows; 1. The trachied transition from earlywood to late wood is very gradual and the tracheids are nearly regular in both arrangement and size in compression wood but this transition in opposite wood and side wood is abrupt and the tracheids in opposite wood and side wood are less regular than those in compression wood. Also, the annual ring width of opposite wood is narrower than that of compression wood or side wood and the rays revealed on cross surface of side wood are more distinct than compression wood and opposite wood rays. 2. The tracheids of compression wood show roundish trends especially in earlywood but those of opposite wood and side wood show some angular trends. And intercellular space, helical cavity, and spiral check are present in both earlywood and latewood of compression wood but not present in opposite wood and side wood irrespective of earlywood and latewood. 3. The wall thickness of latewood tracheid is similar to that of earlywood tracheid in compression wood whereas the wall thickness of latewood tracheid is by far thicker than that of earlywood tracheid in opposite wood and side wood and the S3 layer of secondary wall is lack in compression wood tracheid unlike opposite wood and side wood tracheid. 4. The tracheids in compression wood are often distorted at their tips unlike those in opposite wood and side wood and the bordered pit in compression wood tracheid is located at the bottom of helical groove unlike that in opposite wood and side wood tracheid. 5. The bordered pits in radial wall of opposite wood and side wood tracheids are oval in shape but those of compression wood tracheids show some modified oval shape. 6. In earlywood of side wood, the small apertures of cross-field pits are roundish triangle to rectangle and the large one are fenestriform through the coalition of two small ones. However, the small apertures of cross-field pits are upright oval and the large ones are procumbent oval shape in earlywood of opposite wood and the apertures of cross-field pits in compression wood are tilted bifacial convex lens shape in earlywood and slit in late wood because of the border on tracheid side.