• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.83-93
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• 2023

This study compares the abundance and community structure of zooplankton organisms from pelagic regions, and considers particularly the trophic levels vs. zooplankton abundances and biomass. Zooplankton samples were collected three times from May to November 2022, at 30 temperate lakes and reservoirs, which belong to four different river basins. The total zooplankton abundance, biomass and species index were showed considerable spatial variation. The spatial pattern of rotifer abundance was similar to that of total zooplankton abundance, while there were not showed similar patterns of zooplankton biomass (㎍ L^-1) in lentic ecosystems. The rotifer strongly dominated the zooplankton assemblage in smaller lentic system than that of larger. A total of 130 species of zooplankton were identified (83 rotifers, 34 cladocerans and 13 copepods). The total average of zooplankton abundance and biomass were 213.7±342.3 Ind. L^-1 (n=129) and 1382.8±1850.4 ㎍ L^-1, respectively. Total and average of zooplankton abundance were usually dominated by the rotifers (>56.9%), while those of zooplankton biomass were dominated by the cladocerans and copepods (>73.6%) in lentic ecosystems. Considering the Trophic State Index (TSI), the factors of zooplankton abundance and biomass were included in between meso- and eutrophic states(27 lakes, 90% of all). The mean abundance and biomass of zooplankton in eutrophic systems were higher than that of meso- and hypertrophic systems. From this result, we suggest that management strategy for the lentic ecosystem water environment has to be focused more on small-sized lakes and reservoirs, in terms of zooplankton assemblages.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.61-67
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• 2015

As the production of palm oil has been increased, the generation of oil palm biomass is also increased and the utilization of the oil palm biomass become more significant topic. One third of the oil palm biomass is empty fruit bunch (EFB) and the other two thirds are oil palm trunks and fronds. However, the effective use of oil palm biomass has not been developed and most of it is discarded near oil palm plants. In this study, we investigated the applicability of EFB to the paperboard mills, as an organic filler. The new organic filler was manufactured in a laboratory by grinding and fractionating dried EFB powder, and its properties were analyzed. The particles of EFB organic filler were larger and more spherical than those of the commercial wood powder. The use of EFB organic filler resulted in a higher bulk of the handsheets with similar trends of physical strength, compared to those made with wood powder. It was concluded that EFB could be used as a raw material to manufacture organic filler for paperboard production.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.249-255
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• 2000

This study has been carried out to estimate aboveground biomass and net primary production in a 22-year-old Betula platyphylla and 24-year-old juglans mandshurica plantations. Nine sample trees were cut in each plantation. Estimations for aboveground biomass and net primary production were made by the equation model $Wt=aD^b$ where Wt is ovendry weight in kg and D is DBH in cm. Total aboveground biomass was 79.33t/ha in Betula platyphylla plantation and 67.47t/ha in Juglans mandshurica plantation. The proportion of each tree component to total aboveground biomass was high in order of bolewood, branches, bolebark, and leaves in the two plantations. Aboveground total net primary production was estimated at 9,92t/ha in Betula platyphylla plantation and 11.79t/ha in Juglans mandshurica plantation. There was greater net primary production in Juglans mandshurica plantation than in Betula platyphylla plantation because of greater bolewood, bolebark, current twig, and branch net primary productions in Juglans mandshurica plantation than in Betula platyphylla plantation.

• Journal of Forest and Environmental Science
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• v.33 no.4
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• pp.330-341
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• 2017

Tropical forests play a key role for functioning of the planet and maintenance of life. These forests support more than half of the world's species, serve as regulators of global and regional climate, act as carbon sinks and provide valuable ecosystem services. Forest floor biomass and litterfall dynamics was measured in different sites influenced by fire in a seasonally dry tropical forest of Bhoramdeo wildlife sanctuary of Chhattisgarh, India. The forest floor biomass was collected randomly placed quadrats while the litterfall measured by placing stone-block lined denuded quadrat technique. The seasonal mean total forest floor biomass across the fire regimes varied from $2.00-3.65t\;ha^{-1}$. The total litterfall of the study sites varied from $4.75-7.56t\;ha^{-1}\;yr^{-1}$. Annual turnover of litter varied from 70-74% and the turnover time between 1.35-1.43 years. Monthly pattern of forest floor biomass indicated that partially decayed litter, wood litter and total forest floor were differed significantly. The seasonal variation showed that leaf fall differed significantly in winter season only among the fire regimes while the wood litter was found non significant in all the season. This study shows that significant variation among the site due to the forest fire. Decomposition is one of the ecological processes critical to the functioning of forest ecosystems. The decomposing wood serves as a saving account of nutrients and organic materials in the forest floor. Across the site, high fire zone was facing much of the deleterious effects on forest floor biomass and litter production. Control on such type of wildfire and anthropogenic ignition could allow the natural recovery processes to enhance biological diversity. Chronic disturbances do not provide time for ecosystem recovery; it needs to be reduced for ecosystem health and maintaining of the high floral and faunal biodiversity.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.171-178
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• 2016

Extensive efforts from all over the world have been made to solve energy problems, such as high oil prices, global warning due to the depletion of oil. Among them, biofuel has been drawing attention as a clean energy, which can replace fossil fuels. However, conventional biofuels were often converted from eatable biomass such as sugar cane, corn and soy which should be replaced with uneatable biomass. In this study, a techno-economical evaluation of the gasification of biomass waste with mixed alcohol synthesis process was performed. Considering available domestic biomass wastes, a 2000 ton/day conversion plant were assumed to produce 533000 L/day ethanol. Also, financial data from previous studies were evaluated and used and economical sensitivities with various operation conditions were established. Economic analysis were conducted by the payback period and internal rate of return (IRR) and net present value (NPV). Sensitivity analyses of raw material costs, initial investment, the major process cost, ethanol price changes and operating costs were all performed.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.507-512
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• 2018

Three natural Pinus thunbergii stands in southern Korea were studied to investigate stem density, biomass expansion factors, allometric equations and stand biomass. Stand ages of stand 1, 2 and 3 were 15, 29 and 45 years old, respectively. Three $10m{\times}10m$ plots were set up, five sample trees were cut and roots of three sample trees were excavated for dimension analysis in each stand. Stem density of stand 1, 2 and 3 were $0.450g/cm^3$, $0.440/cm^3$ and $0.457g/cm^3$, respectively, and there was no significant difference among the three stands. Biomass expansion factors of above-ground and total tree decreased with increasing stand age. Above-ground biomass expansion factor of stand 1 was significantly higher than those of stand 2 and 3, and total tree biomass expansion factor of stand 1 was significantly higher than that of stand 3. Allometric equations were developed for the 15 sample trees of the three stands based on D or $D^2H$. Above-ground biomass of stand 1, 2 and 3 were 50.72t/ha, 89.92t/ha, 194.07t/ha, respectively, and total tree biomass of stand 1, 2 and 3 were 61.62t/ha, 113.12t/ha, 248.36t/ha, respetively.

• Journal of Forest and Environmental Science
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• v.38 no.3
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• pp.184-194
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• 2022

Triplochiton scleroxylon K. Schum is the plant species most affected by logging activities in the East Region of Cameroon due to its market value. This logging has impacted the ecological niche of the fern plant for which limited research has been done. The aim of this study is to contribute towards improving knowledge of fern richness and biomass on T. scleroxylon within the Central African sub-region. Fern data collection was done on 20 felled/harvested T. scleroxylon where, in addition to fern inventory, fern biomass was collected by the destructive method. The diameter and height of T. scleroxylon measured were used as explanatory variables in allometric equations for fern biomass estimation. Fern inventory was characterized using diversity index. Eight fern species were recorded on T. scleroxylon (≈5 species/T. scleroxylon). The minimum diameter where fern could be found is 59.4 cm. The average fern biomass found was 23.62 kg/T. scleroxylon. Pearson correlation coefficient showed a positive correlation (r>0.55) between fern biomass and T. scleroxylon diameter. For allometric equation, the logarithmic model improved better the adjustment than the non-logarithmic model. However, the quality of the adjustment is improved more when only the diameter is considered as an explanatory variable. Fern biomass is estimated to 90.08 kg/ha^-1 with 76.02 kg/ha^-1 being lost due to T. scleroxylon exploitation in the study area. This study is a contribution towards increasing knowledge of fern diversity specific to T. scleroxylon, and also fern biomass contribution to climate change mitigation and the potential carbon loss due to T. scleroxylon exploitation.

• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.417-430
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• 2014

We have found an error in the operational OMI HCHO columns, and corrected it by applying a background parameterization derived on a 4th order polynomial fit to the time series of monthly average OMI HCHO data. The corrected OMI HCHO agrees with this understanding as well as with the other sensors measurements and has no unrealistic trends. A new scientific approach, statistical analyses with EOF and SVD, was adapted to reanalyze the consistency of the corrected OMI HCHO with other satellite measurements of HCHO, CO, $NO_2$, and fire counts over Africa. The EOF and SVD analyses with MOPITT CO, OMI $NO_2$, SCIAMAHCY, and OMI HCHO show the overall spatial and temporal pattern consistent with those of biomass burning over these regions. However, some discrepancies were observed from OMI HCHO over northern equatorial Africa during the northern biomass burning seasons: The maximum HCHO was found further downwind from where maximum fire counts occur and the minimum was found in January when biomass burning is strongest. The statistical analysis revealed that the influence of biogenic activity on HCHO wasn't strong enough to cause the discrepancies, but it is caused by the error in OMI HCHO from using the wrong Air Mass Factor (AMF) associated with biomass burning aerosol. If the error is properly taken into consideration, the biomass burning is the strongest source of HCHO seasonality over the regions. This study suggested that the statistical tools are a very efficient method for evaluating satellite data.

• ALGAE
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• v.23 no.1
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• pp.83-90
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• 2008

Eelgrass beds are very productive and provide nursery functions for a variety of fish and shellfish species. Management for the conservation of eelgrass beds along the Korean coasts is critical, and requires comprehensive strategies such as vegetation mapping. We suggest a mapping method to spatial distribution and quantify of eelgrass beds using a digital echosounder. Echosounding data were collected from the northeast part of Kwangyang Bay, on the south of Korea, in March, 2007. A transducer was attached to a boat equipped with a DGPS. The boat completed a transect survey scanning whole eelgrass beds of 11.7 km2 with a speed of 1.5-2 m s-1 (3-4 knot). The acoustic reflectivity of eelgrass allowed for detection and explicit measurements of canopy cover and height. The results showed that eelgrass bed was distributed in depth from 1.19 to 3.6 m (below MSL) and total dry weight biomass of 4.1 ton with a vegetation area of 4.05 km2. This technique was found to be an effective way to undertake the patch size and biomass of eelgrass over large areas as nondestructive sampling.

• Journal of Forest and Environmental Science
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• v.33 no.1
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• pp.22-32
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• 2017

An experiment was set to assess the effect of mixed plantings on initial growth and biomass yield of two common plantation tree species of Bangladesh namely Acacia auriculiformis (A) and Gmelina arborea (G). Study was carried out in the nursery bed of the Seed Research Laboratory and Nursery of Institute of Forestry and Environmental Sciences, Chittagong University (IFESCU), Bangladesh during February to November, 2015. The treatments consisted of two pure planting plots (100% A and 100% G) and five mixed planting plots (50%A: 50%G, 35%A: 65%G, 25%A: 75%G, 65%A: 35%G and 75%A: 25%G) of these two species. In nursery, seedlings were raised in a randomized blocks with four replicates of seven treatment plots. Periodic increments on height (cm), collar diameter (cm) and leaf/phyllode number of the seedlings was taken in every month and continued up to 10 months. The growth and biomass yield of seedlings were measured 10 months after the first seed was emerged. The effects of mixed plantation on growth and biomass were compared to that of seedlings grown in pure plantation. At the age of 10 months it was found that G. arborea seedlings were significantly tallest (240.13 cm) when planted with A. auriculiformis in a proportion of 25%A: 75%G, whereas A. auriculiformis were tallest in the pure 100% A plot, with an average mean height of 135.36 cm. Maximum collar diameter (1.38 cm) was recorded for G. arborea in the mixed plots 75%A: 25%G. Fresh and dry weight of shoots and roots of the seedlings were found significantly (p<0.05) highest in 50%A: 50%G plot for G. arborea. G. arborea also showed highest quality index when mixed with A. auriculiformis in a proportion of 50:50, with an average value of 8.96. The results revealed a positive correlation between seedling growth and various planting patterns.