• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.602-608
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• 2007

Forest plantations become important strategy not merely for the financial aspect, but for carbon sequestration and ecosystem stability. Forest plantations increase the density of the forest biomass, which reduce the increase in atmospheric carbon dioxide. Biomass density is also a useful variable for comparing structural and functional attributes of forest ecosystems across a wide range of environmental conditions. In this study, carbon sequestration of teak (Tectona grandis Linn. f.) in the individual tree and plantation levels estimation was carried out Site-specific allometric equation for the estimation of teak tree biomass was developed based on the direct measurement of fifteen (15) harvested trees in the Oak-twin Township of the Bago Yoma Region, Myanmar. A regression equation of the diameter at breast height (DBH) and the aboveground biomass (carbon content) was constructed to estimate the carbon storage level of plantations, which averaged 79 ton/ha. The average carbon accumulation in the soil (up to 30 cm in depth) was estimated 38.89 ton/ha, The highest mean annual increment (MAI) of total carbon was found in the 6-yr-old teak plantation (12.10 ton/ha/yr) whereas the lowest MAI was in the 26-yr-old teak plantation (4.31 ton/ha/yr).

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.391-396
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• 2010

To analyze the characteristics of canopy fuel in Pinus densiflora stand, which is essential to assess the crown fire hazard, allometric equations for estimation of crown fuel biomass were developed by subjectively categorized crown fuel component and crown bulk density was analyzed by available fuel component categories. Ten trees were destructively sampled at Pinus densiflora stand in Mt. Palgong in Daegu and their crown fuels were weighed separately for each fuel category by size classes and by living and dead. Regression equations that estimate crown fuel load by diameter at breast height(D) or additional total height(H) were derived. The adjusted coefficient of determination values were the highest (${R^2}_{adj}$=0.835-0.996) and standard error of estimate were the lowest (SEE=0.074-0.638) in the allometric equation lnWt=${\alpha}+{\beta}lnD+{\gamma}lnH$ in average. However, in needles and small branches categories, the differences in ${R^2}_{adj}$ and SEE between equations were not significant. Crown bulk density (CBD), which was calculated by crown fuel load divided by crown volume, was 0.067 kg/$m^3$ in average when only needles were considered as available crown fuel and 0.097 kg/$m^3$ when needles and branches (0-0.5 cm diameter) were considered. The increments of CBD of needles and small branches were little even when diameter at breast height increased.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.1
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• pp.29-38
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• 2014

Allometric equations for leaf, branch, stem and total above ground biomass of Pinus koraeinsis trees were developed with diameter at breast height(DBH) of trees, which were growing in a pine plantation with the stand density of 410 tree $ha^{-1}$ and the average DBH of $29.1{\pm}5.2$ cm in Mt. Taewha, Gyeonggi. Damage by Acantholyda parki reduced leaf biomass compared to other studies, however, its contribution to total biomass was minimal among parts. Comprehensive analysis revealed that constant in allometric equation for total above ground biomass (logY=a + blogX) was affected by average DBH and stand density, however, constant b was not. At the stand level, biomass for leaf, brach, stem, total above ground biomass were 6.68 Mg $ha^{-1}$, 18.82 Mg $ha^{-1}$, 101.02 Mg $ha^{-1}$, 126.53 Mg $ha^{-1}$, respectively. We developed a Korean pine stand biomass regression, which explained about 98% of variation with DBH and stand density based on comprehensive analysis.

• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.244-250
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• 2019

We investigated the relationship between morphological characteristics and individual dry weight to develop a method for estimating the individual dry weight of sheet form macroalgae: Ulva australis, Ulva linza, Pachymeniopsis lanceolata, and Pyropia yezoensis. In Total, 319 thalli of various sizes were collected at six sites from February 2017 to December 2018. An interspecific allometric exponent of 0.28 was found for length-biomass allometry in four sheet form macroalgae, corresponding to a 1/4-power law for primary producers. The relationships between surface area and individual dry weight, as well as between individual fresh weight and individual dry weight, were found to fit significantly using linear regression equations. This explained 94-99 % of individual dry weight, indicating that surface area and individual fresh weight can be used to accurately estimate individual dry weight. We propose the use of this method when experimental processes do not allow individual dry weight to be measured directly, so researchers can save both time and expense.

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.100-110
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• 2024

Biometric evaluation and reproductive biology of Oreochromis niloticus were studied from Geray Reservoir. Between November 2021 and August 2022, 316 O. niloticus specimens were collected from this reservoir. The observed male to female sex ratio was 1:1.14, which was statistically insignificant compared with the hypothetical 1:1 sex ratio (X² = 1.27, p > 0.05). The length-weight relationship was curvilinear with allometric growth (b < 3) and statistically significant from the expected isometric growth pattern (b = 3). The regression equation for females was TW = 0.0264TL^2.72 (r² = 0.90, n = 168), males (TW = 0.0183TL^2.79, r² = 0.93, n = 148), and combined sexes (TW = 0.0229TL^2.76, r² = 0.91, n = 316). Gonadosomatic index (GSI) ranged from 0.8 to 1.4 (males) and 1.8 to 4.9 (females). The breeding season lasted from March to June, with a GSI peak in April. Fecundity ranged from 279 to 1,528 eggs./fish, with a mean of 1,025 eggs./fish. The correlation between absolute fecundity and length was more significant (F = 0.76TL^2.8, R² = 0.94, p < 0.05) than with weight (F = 17.683TW^0.71, R² = 0.92, p < 0.05). This study provides basic information on the biology of O. niloticus in the Geray Reservoir for future fishery management tools for the conservation and utilization of this valuable freshwater fish.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.163-168
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• 2005

This study was carried out to estimate above-ground biomass and inorganic nutrient distribution for a Camellia japonica stand located Mt. Cheon-gwan, Jeonnam province. Regression analysis of biomass for stem, current twig, branch and foliage versus diameter at breast height(DBH) was used to calculate regression equations of the form of logY = a + blogD(Y: component biomass, D: DBH). Total above-ground biomass for a Camellia japonica stand was 115.2 ton/ha(47.9 for main stem, 1.4 for current twig, 53.4 for live and dead branch, 5.6 for current foliage and 6.9 for ${\geq}1$-yr-old foliage). Component biomass was non-linearly correlated with DBH, and the difference in biomass between ${\geq}1$-yr-old and current foliage increased in proportion to DBH. Current foliage and live branch showed higher N, P and K concentrations compared to ${\geq}1$-yr-old foliage and dead branch, respectively. However, Ca concentration of current foliage and live branch was lower than that of ${\geq}1$-yr-old foliage and dead branch, respectively. Total above-ground inorganic nutrient contents(kg/ha) were distributed as follows; K: 366.4. N: 442.7, Ca: 433.3, Mg: 118.4, P: 50.5 and Na: 25.3. The proportions of inorganic nutrient content for live branch were generally the highest in all the inorganic nutrients.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.161-167
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• 2005

Above and belowground biomass for Phyllostachys pubescens was determined in Jinju, Gyeongsangnam-do. Regression analyses of dry weights of culms, foliages, and twigs versus diameter at breast height were used to calculate regression equations of the form of log Y = a + blogX. Total aboveground biomass for Phyllostachys pubescens was 69.7 ton/ha and rhizomes and roots biomass were 13.7 ton/ha and 7.5 ton/ha, respectively. Culms account for about 60% of total aboveground biomass. The aboveground biomass of each component was decreased in the order of culms>foliages>twigs. As diameter at breast height grew thicker, the proportion of culms to total aboveground biomass increased. The proportion of dry weight of culms to green weight gradually increased with height in a bamboo tree and ages. Nutrients (kg/ha) of litter layer were distributed as follows: N(45.1), Ca(17.3), K(6.1), Mg(3.6), P(3.5) and Na(0.7). Nitrogen and K were given much weight in total nutrients of rhizomes and roots. These results will be useful in measuring carbon stock and drawing up management plan to increase it for Phyllostachys pubescens stand.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.127-136
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• 2015

This study aims to quantify the stand-level above ground biomass in intact tropical rain forest of Brunei using airborne LiDAR data. Twenty four sub-plots with the size of 0.09ha ($30m{\times}30m$) were located in the 25ha study area along the altitudinal gradients. Field investigated data (Diameter at Breast Height (DBH) and individual tree position data) in sub-plots were used. Digital Surface Model (DSM), Digital Terrain Model (DTM) and Canopy Height Model (CHM) were constructed using airborne LiDAR data. CHM was divided into 24 sub-plots and 12 LiDAR height metrics were built. Multiple regression equation between the variables extracted from the LiDAR data and biomass calculated by using a allometric equation was derived. Stand-level biomass estimated from LiDAR data were distributed from 155.81 Mg/ha to 597.21 Mg/ha with the mean value of 366.48 Mg/ha. R-square value of the verification analysis was 0.84.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.43-60
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• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.