• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.161-171
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• 2023

The medium-large cladoceran species Simocephalus spp. predominantly occur in habitats with developed aquatic vegetation. Accordingly, due to Simocephalus' high contribution to zooplankton community biomass in the lake's littoral zone and wetland habitats, estimating their biomass is important to understand the matter cycling based on biological interactions within the aquatic food web. In this study, we reviewed the length-weight regression equations used previously to estimate Simocephalus biomass, directly measured S. serrulatus' body specification (length, width and area) and their biomass(dry weight) using instruments such as a microscopic digital camera and a microscale, and performed regression analysis between each other. When S. serrulatus biomass was estimated using the equation (Kawabata and Urabe, 1998) presented in 『Biomonitoring Survey and Assessment Manual』, Korea, errors between estimates and measures were relatively large compared to the S. serrulatus species-specific biomass estimate equation developed by Lemke and Benke (2003). In addition, both equations showed not only increasing trends in error (estimate-measure) with increasing S. serrulatus' body length, but also in error variance among similar-sized individuals. The results of regression analysis with dry weight by body specifications indicated that the most appropriate equation for estimating the biomass of S. serrulatus was derived from the width-dry weight exponential regression equation (R²=0.9555). The review and development study of such species-specific biomass estimation equations for zooplankton can be used as a tool to understand their role and function in aquatic ecosystem food webs.

• New & Renewable Energy
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• v.18 no.4
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• pp.70-78
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• 2022

To respond to global warming, there is an increasing interest in eco-friendly alternative energy sources. Therefore, unused forest biomass that has been neglected due to a lack of marketability is attracting attention. With the introduction of the "unused forest biomass certification system" in 2019, ways of determining quantity of unused forest biomass have steadily increased. However, there have been reported cases whereby unused forest biomass weighed more than the amount of harvested trees. It was found that it was possible that forest resources that can be used as round wood were mixed with unused forest biomass. In this context, this study aimed to estimate the amount of mixed round wood in the unused forest biomass supply. The relative expression of growing stock/ha versus the amount of final clearing/ha collected was modeled (y=1.490x-94.341, R²=0.861). As a result, it was found that round wood was mixed into the unused forest biomass, contributing to the disparity observed between the weighted forest biomass and the amount of trees harvested. In conclusion, proper declaration and certification procedures should be carried out for the use of forest resources and promoting unused forest biomass usage.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.485-488
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• 2006

Allometric equations for biomass measurement of the shrub species, Lindera obtusiloba, were developed. The allometric equations between $(BD)^2H$ and dry weight of leaves ($W_I$), stems and branches ($W_{sb}$), roots ($W_r$) and total weight ($W_t$) of the Lindera obtusiloba were as follows: $W_I=0.7318\;(BD^2H)^{0.6108},\;W_{sb}=0.6067(BD^2H)^{0.8355},\;W_r=0.4524(BD^2H)^{0.7608},\;W_t=1.672 (BD^2H)^{0.7664}$. The $R^2s$ between $(BD)^2H\;and\;W_I,\;W_{sb},\;W_r\;and\;W_t$ of the Lindera obtusiloba were 0.9251, 0.9571, 0.9353 and 0.9546, respectively. Root weight of this Lindera obtusiloba was about 38% of the aboveground biomass.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.351-356
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• 2006

This study developed an artificial neural network (ANN) to estimate the growth of microorganisms during a fermentation process. The ANN relies solely on the cumulative consumption of alkali and the buffer capacity, which were measured on-line from the on/off control signal and pH values through automatic pH control. The two input variables were monitored on-line from a series of different batch cultivations and used to train the ANN to estimate biomass. The ANN was refined by optimizing the network structure and by adopting various algorithms for its training. The software estimator successfully generated growth profiles that showed good agreement with the measured biomass of separate batch cultures carried out between at 25 and $35^{\circ}C$.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.113-120
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• 2004

The biodegradability of organics has become essential for the design and modeling of a biological nutrient removal process. Respirometry for the batch test just with wastewater has been conducted to estimate active biomass and readily biodegradable organics in municipal wastewater simultaneously. Municipal wastewater contains significant active biomass, which is estimated about 17% of COD. Compared to the batch test seeded with sludge, the batch test just with wastewater represents a little higher readily biodegradable organics. This might be due to the different environment of the logarithmic growth of active biomass. The nitrate uptake rate test has been also performed for the estimation of the readily biodegradable organics. The nitrate uptake rate test results in a little higher readily biodegradable organics compared to the batch test seeded with sludge and similar organics compared to the batch test just with wastewater. This might be caused by the different sludge of a sequencing batch reactor process. Taking the result of the previous research into account, the readily biodegradable, slowly biodegradable, active biomass, soluble inert, and particulate inert organics are estimated about 11%, 49%, 17%, 11%, and 12% of COD, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.2
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• pp.128-136
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• 2012

Hybrid surveys using hydroacoustic and fish sampling gears such as trammel net, trap were conducted to investigate total biomass, distribution and dominant fish species of the demersal fishes in the marine ranching area (MRA) of Jeju. Four surveys were carried out in June, August, October and November using 38kHz quantitative echo sounder. Catch data using trammel net and trap were used to calculate biomass and to examine dominant fish species. Fish schools were mainly detected in the waters of 20 meters below and around Chagwido waters. By the result of fishing experiments, fish species living in MRA of Jeju were about 40 species, dominant fish species of a detectable fish such as Family Sparidae and Family Monacanthidae etc. were identified 59.4~68.8% of total biomass. Based on the hydroacoustic data, fish length-weight function and target strength information, mean density of the demersal fish estimated were as follows; 0.88g/$m^2$ on June, 1.12g/$m^2$ on August, 1.35g/$m^2$ on October and 1.18g/$m^2$ on November. An estimated average biomass in MRA of Jeju was founded 20.5 tons in 2007, 20.6 tons in 2008, 23.0 tons in 2009, 25.9 tons in 2010. The results showed that biomass of MRA is getting increased slowly. Therefore the hybrid survey method using hydroacoustic and fish sampling gears is assured an effective biomass survey in the waters of mixed species.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.25-31
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• 2002

This study was carried out to estimate aboveground biomass and net primary production in an average 37-year-old Quercus acutissima stand of Pohang area. Ten sample trees were cut in the forest and soil samples were collected in August, 2001. Estimation for aboveground biomass and net primary production was 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 115.47ton/ha in the study forest. The proportion of each tree component to total aboveground biomass was high in order of bolewood(63.9%), branches(19.8%), bolebark(16.2%) and leaves(1.2%) in the study forest. Aboveground total net primary production was estimated at 7.89ton/ha in the study area. The proportion of each tree component to total net primary production was high in order of bolewood, bolebark, branch, and leaves.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.196-206
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• 2024

Background: Most of the biomass equations were developed using sample trees collected mainly from pan-tropical and tropical regions that may over- or underestimate biomass. Site-specific models would improve the accuracy of the biomass estimates and enhance the country's measurement, reporting, and verification activities. The aim of the study is to develop site-specific biomass estimation models and validate and evaluate the existing generic models developed for pan-tropical forest and newly developed allometric models. Total of 140 trees was harvested from each diameter class biomass model development. Data was analyzed using SAS procedures. All relevant statistical tests (normality, multicollinearity, and heteroscedasticity) were performed. Data was transformed to logarithmic functions and multiple linear regression techniques were used to develop model to estimate aboveground biomass (AGB). The root mean square error (RMSE) was used for measuring model bias, precision, and accuracy. The coefficient of determination (R² and adjusted [adj]-R²), the Akaike Information Criterion (AIC) and the Schwarz Bayesian information Criterion was employed to select most appropriate models. Results: For the general total AGB models, adj-R² ranged from 0.71 to 0.85, and model 9 with diameter at stump height at 10 cm (DSH₁₀), ρ and crown width (CW) as predictor variables, performed best according to RMSE and AIC. For the merchantable stem models, adj-R² varied from 0.73 to 0.82, and model 8) with combination of ρ, diameter at breast height and height (H), CW and DSH₁₀ as predictor variables, was best in terms of RMSE and AIC. The results showed that a best-fit model for above-ground biomass of tree components was developed. AGB_Stem = exp {-1.8296 + 0.4814 natural logarithm (Ln) (ρD²H) + 0.1751 Ln (CW) + 0.4059 Ln (DSH₃₀)} AGB_Branch = exp {-131.6 + 15.0013 Ln (ρD²H) + 13.176 Ln (CW) + 21.8506 Ln (DSH₃₀)} AGB_Foliage = exp {-0.9496 + 0.5282 Ln (DSH₃₀) + 2.3492 Ln (ρ) + 0.4286 Ln (CW)} AGB_Total = exp {-1.8245 + 1.4358 Ln (DSH₃₀) + 1.9921 Ln (ρ) + 0.6154 Ln (CW)} Conclusions: The results demonstrated that the development of local models derived from an appropriate sample of representative species can greatly improve the estimation of total AGB.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.317-330
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• 2022

Recently, the policy regarding climate change in Korea and overseas has been to promote the utilization of forest biomass to achieve net zero emissions. In addition, with the implementation of the unused forest biomass system in 2018, the size of the Korean market for manufacturing wood pellets and wood chips using unused forest biomass is rapidly expanding. Therefore, it is necessary to estimate the total amount of unused forest biomass that can be used as an energy source and to identify the capacity that can be continuously produced annually. In this study, we estimated the actual forest area that can be produced of logging residue and the potential amount of unused forest biomass resources based on GT (green ton). Using a forest functions classification map (1 : 25,000), 5th digital forest type map (1 : 25,000), and digital elevation model (DEM), the forest area with a slope of 30° or less and mountain ridges of 70% or less was estimated based on production forest and IV age class or more. The total forest area where unused forest biomass can be produced was estimated to be 1,453,047 ha. Based on GT, the total amount of unused forest biomass potential resources in Korea was estimated to be 117,741,436 tons. By forest type, coniferous forests were estimated to be 48,513,580 tons (41.2%), broad-leaved forests 27,419,391 tons (23.3%), and mixed forests 41,808,465 tons (35.5%). Data from this research analysis can be used as basic data to estimate commercial use of unused forest biomass.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.138-147
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• 2012

For biomass estimation of Phyllostachys pubescens stands by optimal survey method we established 9 bamboo sample plots in the research forests of KFRI (Korea Forest Research Institute). The dry weight of culm segment determined by relative heights of total bamboo height show us two groups of 1st to 5th culm segment (up to 0~55% culm of tree height from the bottom area) and 6th to 8th culm segment (55~100%) by the results of cluster analysis for dry weight ratio. This results show that upper and lower part of 55~70% reference height from the bottom area against total culm height can be used in obtaining 1 kg of a sample bamboo, respectively, rather than 2.0 m stem segments of other forest tree species. In above-ground biomass estimation by $W=aD+bD^2$ having the highest coefficient of determination in this study, above ground stand biomass was 57.77 ton/ha (culm 40.47 ton/ha, branch 9.29 ton/ha, and leaf 8.01 ton/ha) of which 70% was contributed by culm component followed by branch (16%) and leaf (14%). Below-ground biomass was 53.35 ton/ha in total.