• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.515-522
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• 2023

The aim of this study was to quantitatively evaluate a new stem volume table for estimating the growth, carbon storage, and greenhouse gas (GHG) absorption in Cryptomeria japonica and Chamaecyparis obtusa stands and to provide suggestions for improving the domestic GHG inventory. Carbon storage and GHG absorption were estimated using growing stock data obtained from invariable sub-sample plots between the 6^th and 7^th national forest inventories. We assessed changes in growing stock using the parameters employed by Kozak (1988) and Versions 1 and 2 of the stem volume table. Version 2 has new stem tables for 16 species, including Cryptomeria japonica, which were unavailable in Version 1. Version 2 also includes new data for trees with diameters at breast height equal to or greater than 30 cm. We found greater growing stock values using Version 2 than Version 1 for both stands, and the differences were statistically significant (p<0.001). Applying the new stem volume table increased GHG absorption by 22% for the Cryptomeria japonica stand and 13% for the Chamaecyparis obtusa stand. The growing stock estimation method used in this study should therefore be applied to re-estimate GHG absorptions in the forestry sector to produce accurate statistics for the IPCC guidelines.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.21-30
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• 1977

Japanese larch (Larix leptolepis) is one of main timber species in Korea that could find much plantation and growing stands on all over the country. It is thought to be in meaningful that a guiding diagram for density control of Japanese larch stands is made to estimate easily the density conditions in the quantitaive, ecological and economic viewpoint. Sample plots for this study are selected from the stands that have not been thinned in recent years, and mean height, mean diameter, dominant height, tree numbers per hectare and stem volume of mean tree are calculated from the each sample plots among total 165 plots In this study, especially, the theory of slenderness of mean tree are applied, that have been identified through the results of the spacing trial. Relative growth characteristics of this species are calculated from the general logistic curve and its formula is $Y=ax^b$. Relatwion between the measured items are found out as follows: 1. Relation between the mean height and tree numbers per hectare by slender class is showing the high correlation as table 1 and fig. 2, and between mean diameter and tree numbers per hectare is also high correlation as table 1 and fig 3. 2. The stem volume can be correctly estimated from height in case that slender class may be known, as showing in table 3 and fig. 4. 3. The stem volume can be more correctly estimated from the relation with $D^2H$ as formula, $Log_e\;V=0.9569\;Log_eD^2H-9.8431$, and relation between stem volume of single tree or volume per hectare and tree numbers per hectare are as following formulas: $Log_e$ stem volume=9.5026-1.6800 $Log_e$ tree numbers per hectare $Log_e$ stem volume per hectare=9.4911-0.6784 $Log_e$ tree numbers per hectare. Stem volume of mean tree, tree numbers per hectare and stem volume per hectare correspond to the mean tree height are calculated to slender class as table 5, 6, 7. Through the above steps, the diagram for density control of Japanese larch are produced as fig. 9. It is thought that this diagram could be applied to control the density of Japanese larch stands.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.461-467
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• 2020

The aim of this study was to utilize Kozak's stem taper model to develop both a stem taper equation and a stem volume table for Criptomeria japonica, a tree species distributed across Korea. A total of 1,000 sample trees were cut and collected across the country to measure their diameters by stem height. The equation was then used to estimate examine their stem shapes. Our results show that the Fitness Index for the equation was 98.7%, the Mean Absolute Deviation (MAD) was -0.0142, and the MAD was 1.1640, thus indicating a high level of fitness. A statistically significant difference (p < 0.05) was also found from the analysis of discrepancies between a current table and the new table used in this study. It is therefore suggested that the new table-with data from actual stands-will contribute to enhancing the accuracy of national and municipal forest statistics and reducing losses caused by imprecise data on available forest resources.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.40-47
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• 2007

The objectives of this study were to derive site index and stem volume prediction equation based on stem analysis data for Larix leptolepis in Jinan region. The function for site index was developed by algebraic difference equation method. Polymorphic site index family curves with base age of 40 were presented based on the Schumacher height equation. The best stem volume prediction equation was suggested as $V=0.00260+0.00000399D^2H$. The simultaneous F-test using this equation showed that the estimated tree stem volumes were not significantly different (${\alpha}=0.05$ level) from the observed stem volumes for model evaluation. Therefore, site index and volume prediction equations prepared in this study could provide an indication of site quality and basic information for making of yield table, and could be used for rational forest management of Larix leptolepis stands grown in Jinan region.

• Journal of Climate Change Research
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• v.8 no.4
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• pp.415-424
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• 2017

This study was conducted to estimate carbon stocks of Pinus densiflora with drawing volume of trees in each tree height and DBH applying the suitable stem taper equation and tree specific carbon emission factors, using collected growth data from all over the country. Information on distribution area, tree age, tree number per hectare, tree volume and volume stocks were obtained from the $5^{th}$ National Forest Inventory (2006~2010) and Statistical yearbook of forest (2016), and method provided in IPCC GPG was applied to estimate carbon stock and uptake. Performance in predicting stem diameter at a specific point along a stem in Pinus densiflora by applying Kozak's model, $d=a_{1}DBH^{a_2}a_3^{DBH}X^{b_{1}Z^2+b_2ln(Z+0.001)+b_3\sqrt{Z}+b_4e^z+b_5(\frac{DBH}{H})}$, which is well known equation in stem taper estimation, was evaluated with validations statistics, Fitness Index, Bias and Standard Error of Bias. Consequently, Kozak's model turned out to be suitable in all validations statistics. Stem volume table of P. densiflora was derived by applying Kozak's model and carbon stock tables in each tree height and DBH were developed with country-specific carbon emission factors ($WD=0.445t/m^3$, BEF = 1.445, R = 0.255) of P. densiflora. As the results of analysis in carbon uptake for each province, the values were high with Gangwon-do $9.4tCO_2/ha/yr$, Gyeongsandnam-do and Gyeonggi-do $8.7tCO_2/ha/yr$, Chungcheongnam-do $7.9tCO_2/ha/yr$ and Gyeongsangbuk-do $7.8tCO_2/ha/yr$ in order, and Jeju-do was the lowest with $6.8tC/ha/yr$. Total carbon stocks of P. densiflora were 127,677 thousands tC which is 25.5% compared with total percentage of forest and carbon stock per hectare (ha) was $84.5tC/ha/yr$ and $7.8tCO_2/ha/yr$, respectively.

• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.742-746
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• 2001

This study was carried out to develop volume equations for Japanese Res Cedar(Cryptomeria japonica D. Don) trees which were widely planted from 1920s throughout the southern regions in south Korea. The 31 trees for stem analysis were selected in 6 different sites in the southern and 29 trees data were used for developing volume equation. The best equation in estimating Japanese Red Cedar trees's volume was suggested as $V=-0.002908+0.000125D^{1.907114}H^{0.645131}$. The simultaneous F-test for this equation revealed that the estimated individual tree volume was not significantly different (p=0.1936) from the observed tree volume for model evaluation. Therefore, this individual tree volume prediction equation could provide basic information for the construction of yield table and forest management.

• Journal of Korean Society of Forest Science
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• v.26 no.1
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• pp.13-18
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• 1975

This study was intended to clarify interrelations among seven characters of bamboo and their influences upon its culm-volume. The analysis of covariance was used to obtain phenotypic correlations, genotypic correlations and environmental correlations among some characters of Phyllostachys bambusoides Sieb. et Zucc., and thereby path-coefficients were calculated based on Dewey's method. The characters considered here included the breast height diameter, culm-height, clear-length, subterranean stem, number of bamboo joints, butt-end diameter and culm-volume of bamboo. Average values, standard errors, variances and standard deviations for the characters mentioned above are shown in Table 1, and phenotypic correlations, genotypic correlations and environmental correlations among seven characters are shown in Table 2, according to the results, there are highly significant relationships among lines but not among some replications. According to Table 4, heritability values in the breast height and butt-end diameters are higher than those in other characters mentioned above. On the other hand, environmental correlations among general characters appear to have lower values than phenotypic and genotypic correlations do. It also appears that the butt-end diameter and breast height diameter are highly correlated with the culm-volume of bamboo. The path-coefficients of individual characters to the culm-volume of bamboo are computed from the correlations (Table 4) and presented in Figure 1 and Table 5, where it could shown the direct and indirect effects on the bamboo culm-volume of each character.

• Journal of agriculture & life science
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• v.44 no.4
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• pp.1-7
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• 2010

Data was collected to develop equation for predicting stemp taper for Carpinus laxiflora in Jeju Experimental Forests. The Models tested for choosing the best-fit equations were Max & Burkhart's model, Kozak's model, and Lee's model. Performance of the equations in predicting stem diameter at a specific point along a stem was evaluated with fit and validation statistics and distribution of residuals on predicted values. In result, all the three models gave slightly better values of fitting statistics. In plotting residuals against predicted diameter, Max & Burkhart's model showed underestimation in predicting small diameter and Lee's Model did the same in predicting small diameter. Based on the above analysis of the three models in predicting stem taper, Kozak's model was chosen for the best-fit stem taper equations, and its parameters were given for C. laxiflora. Kozak's model was used to develop a stem volume table of outside bark for C. laxiflora.

• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.330-335
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• 2016

This study was conducted to derive merchantable volume ratio for 5 major species such as Pinus Densiflora (Central Region). The data used for this study was from at least more than 1,300 trees of research data throughout the country. the study applied two estimation equations, which were the estimation equation for wood volume ratio representing total wood volume to total tree stem volume and the estimation equation for merchantability representing ratio of merchantable volume to total wood volume. The merchantable volume ratio was derived by multiplying those two estimation equations. In order to gain wood volume ratio(W) from DBH, $W=\frac{a_1}{1+a_2/D}+\frac{b_1}{1+b_2/D}$ model was used. Fitness index of it was more than 99% by species, and other test statistics also indicated the suitability of this equation enough. Merchantability (M) for wood volume applied $M=e^{a_1\(\frac{d}{D}\)^{a_2}}-(b_0+b_1D+b_2D^2+b_3D^3)$ model and fitness index was more than 96% by species. Merchantable volume ratio was assessed using those two estimation equations by each 5 species, and constructed a merchantable volume ratio table. In result, merchuntable volume ratio was little difference between stand types, but there was slightly different with the existing standard such as conifers of 85% and non-conifers of 70%.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.57-61
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• 2010

Data with collected from 278 trees sampled through out the climatic range of Quercus acuta in Jeju Experiment Forests. The models tested to select the best-fit equations form the Max & Burkhart's model, Kozak's model, and Lee's model. Performance of the equations in predicting of residuals on predicted values. In result, all three models gave slightly better values of fit statistics. In plotting residuals against predicted diameter, Max & Burkhart's model showed underestimation in predicting small diameter and Lee's Model did the same in predicting small diameter. Based on the above analysis of three models in predicting stem taper, Kozak's model was chosen for the best-fit stem taper equations, and its parameter estimates was given for Quercus acuta. Kozak's model was used to develop a stem volume table outside bark for Quercus acuta.