• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.372-381
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• 2024

This study was performed to analyze adequate stand density management criteria for commercial forests of the major coniferous species, Pinus densiflora, P. koraiensis, and Larix kaempferi in South Korea. Relative density (RD) was applied to analyze occurrence of mortality, mean DBH growth, and height-diameter (HD) ratio. The results showed that when RD was 0.7 or higher, the average number of mortality in all three species increased to 15-24 trees/ha, with mortality rates ranging from 20.0%-35.4%. As RD increased, mean DBH growth decreased 0.2-0.5 cm/year by species, but the HD ratio increased 46.9%-71.4%. Consequently, if adequate stand density management criteria are selected with RD 0.7 for P. densiflora and L. kaempferi and RD 0.8 for P. koraiensis, it is considered to increase high-quality timber production with lower mortality and increased growth.

• Journal of Korean Society of Rural Planning
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• v.26 no.1
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• pp.89-99
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• 2020

This study was conducted as a basic research to create a sound and vital ecological environment in the city compared to the appearance characteristics of Gap stream(G-stream), which are the main stream of Banseok stream(B-stream), by analyzing the characteristics of waterbirds, including Wild Spot-billed Duck (S-Duck), that live in B-stream built as ecological stream. The waterbird survey was conducted by the line census for 3.2km, Jukdong-bridge to Jamiseon-bridge, from January to August 2018. The analysis of the survey was conducted with Relative species density(RD) of the emerging waterbird species, the Species diversity and Density Per Unit area for 100㎡(DPU). The waterbird survey results of B-stream was conducted 65 times. The five types of water birds that appeared during the survey were Spot-billed Duck(Anas poecilorhyncha), Teal(Anas crecca), Little Egret(Egretta garzetta), Great Egret(Egretta alba), and Grey Heron(Ardea cinerea). As a result, for S-Duck at B-stream, RD was 89.9%, monthly species diversity was simple as 0.3801 in January, 0.5943 in February and 0.3501 in August. The DPU of the S-Duck was 0.165/100㎡ in the B-Stream survey section which was 4.9 times higher than the main stream section, G-stream. The non-freezing zone of the city's small stream is expected to play an important role as a winter stop for wild birds such as S-Duck during the freezing period of the huge stream. For this reason, considering the ecological characteristics of wild waterbirds such as S-Duck when creating ecological stream, a: space and linear selection of waterways which can minimize the impact of natural enemy and increasing the number of walkers, b: management water-friendly plants in the low flow channel, c: arrangement walking-bicycle road will be necessary.

• Korean journal of applied entomology
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• v.30 no.1
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• pp.65-79
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• 1991

In order to investigate the species composition and the colony density of ants in Mt. Namsan, Seoul, 39 quadrats were installed in 13 vegetations, 443 colonies of ants were collected from June, 1989 to October, 1990. As the result, 4 subfamilies, 23 genera, 28 species was confirmed. Among them, Cerapachys humicola $O_{GATA}$ is new to Korean fauna along with the subfamily Cerapachinae. For the species composition of ant communities in each vegetation, Robinia pseudoacacia vegetation(containing 3 subfamilies, 14 genera, 15 species-53.6% of all colonies collected in Mt. Namsan) and Quercus mongolica vegetation (3 subfamiles, 12 genera, 14 species -50%) showed relatively rich composition, while Platunus orientalis vegetation (3 subfamilies, 3 genera, 3 species) showed the simplest composition. Colony density was the highest in Prunus sargentii vegetation (7.875 colony /$m^2$) and the lowest in Platunus orientalis (1.000 colony/$m^2$). The relative density of Paratrechina flavipes proved to be the highest (RD = 0.422) and that of Cerapachys humicola $O_{GATA}$ Massor aciculatus was the lowest (RD = O. 002 respectively). In the analysis of the similarity of ant communities between each vegetation by S¢rensen's coefficient, Prunus sargentii was very similar to Sorbus alnifolia (0.745) and Pinus densiflora (0.736), but had the lowest similarity to Metasequoia glyptostoboides and Chamaecyparis pisifera vegetation (0.164 respectively). Dominance of ants in each vegetation analyzed by Simpson'formula was found to be high in Platunus orientalis ($\lambda$ = 0.393) and Sorbus alnifolia ($\lambda$ = 0.392) and the lowest in Metasequoia glyptostroboides vegetation($\lambda$= 0.067). The analysis of diversity by reverse Simpson's coefficient revealed that it was high in Metasequoia glyptostroboides ($d_s$ = 14.925), Pinus rigida ($d_s$ = 7.874) and was the lowest in Platunus orientalis vegetation ($d_s$ = 2.545). Evenness calculated by using d. and $d_{max}$(maximal diversity) was high in Metasequoia glyptostroboides ($E_s$ = 0.714) and Chamaecyparis pisifera vegetation ($E_s$ = 0.624). On the contrary, Quercus mongo/ica vegetation had the lowest value of evenness ($E_s$ = 0.182).

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.160-169
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• 2007

The data used to develop distance-independent individual models for natural mixed forests were collected from 712 remeasured permanent sample plots (25,526 trees) of 10-year periodic from 1990 to 2000 in Baihe Forest Bureau of Changbai Mountains, northeast China. Based on analyzing relationship between diameter increment of individual trees with tree size, competitive status, and site condition, the diameter growth models for individual trees of 15 species growing in mixed-species uneven-aged forest stands, that have simple form, good predicting precision, and easily applicable, were developed using stepwise regression method. The main variables influencing on diameter increment of individual trees were tree size and competition, however, the site conditions were not significantly related with diameter increment. The tree size variables (lnDBH and $DBH^2$) were the most significant and important predictors of diameter growth existing in all 15 growth models. The diameter increment was directly proportional to tree diameter for each species. For the competitive factors in growth model, the relative diameter (RD), canopy closure (P), and the ratio of diameter of subject tree with maximum diameter (DDM) were contributed to the diameter increment at a certain extent. Other measures of stand density, such as basal area of stand (G) and stand density index (SDI), were not significantly influenced on diameter increment. Site factors, such as site index, slope and aspect were not important to diameter increment and excluded in the final models. The total variance explained by the final models of squared diameter increment ($R^2$) for all 15 species ranged from 35% to 72% and these results compared quit closely with those of Wykoff (1990) for mixed conifer stands. Using independent data set, validation measures were evaluated for predicting models of diameter increment developed in this study. The result indicated that the estimated precision was all greater than 94% and the models were suitable to describe diameter increment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.45-50
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• 1981

Diurnal changes in leaf stomatal resistances were measured on leaf positions and both surfaces to investigate the stomatal response to irradiance in wheat, var. Chokwang and barley, var. Dongbori 1. Stomatal frequency and size were also determined to explain the control mechanism of gas exchanges in two species. The leaf diffusive resistances of two species decreased, as the sun rose, to minimum at 10 to 11 o'clock a.m. and increased gradually in the afternoon, even faster at sunset. As the adaxial irradiance increased, stomatal resistances decreased sensitively in the range of 30uEm$^{-2}$ㆍsec$^{-1}$ to 150uEm$^{-2}$ㆍsec$^{-1}$ quantum flux density. The stomatal opening of the abaxial surface began at lower irradiance and was completed earlier than the adaxial surface. The adaxial irradiances decreased in order of leaf position, flag, the 2nd, the 3rd leaf, and the stomatal resistances increased in the same order. Even under the same irradiance, the stomatal resistance of lower leaves were higher than those of upper leaves. The stomatal frequencies of lower leaves were less, but the stomatal size was greater than those of upper leaves. Consequently, the relative leaf area occupied by stomatal pores were constant among leaf positions in two species.