• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.287-294
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• 2015

Relationship between growth rate and wood quality was investigated by mechanical properties with Alnus glutinosa L. (24 years old) from 4 different origins of seeds (Bulgary, Italy, United Kingdom and Yugoslavia). Compression strength was in the range of $231{\sim}326kgf/cm^2$, and there was some differences among different origins of seed. Wood cultivated from the seeds of Italy, United Kingdom, and Bulgary showed higher growth rate and had lower compression strength and compression young's modulus. Wood from Yugoslavia seed had the fastest growth rate with higher strength than other three origins of seed. Bending strength was in the range of $426{\sim}727kgf/cm^2$, and there was some differences among the origin of seed. Higher growth rate wood showed higher bending strength and young's modulus than other woods. Trees cultivated from Yugoslavia seed had two times in diameter than other different origins of seeds, also have compressive strength, bending strength than other origins, which can be recommended as best cultivar in Alnus glutinosa L.

• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.422-430
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• 2014

This study was conducted to investigate growth changes of DBH, height, crown width, volume, stem biomass, and dead trees after thinning treatments with different thinning intensity for Korean white pine (Pinus koraiensis) plantation. First thinning was applied with 29~69% intensity based on number of trees in 19-yearold plantation, and trees were measured three times: right after thinning (19-year-old), 5 years later (24-yearold), 12 years later (29-year-old). In the case of DBH growth, average DBH growth of heavily thinned plots was 19.6~19.9% higher 5 years later, and 13.3~24.7% higher 12 years later, compared to that of unthinned plots. Initial diameter growth rate was higher than late growth rate. The proportion of large pole candidates ($DBH{\geq}25cm$) was 31% in heavily thinned plot while only 2% was shown in unthinned plot. No difference was shown in height growth depending on plots, and average crown width growth in heavily thinned plots was 30.6~33.3% higher, 5 years later, and 35.0~40.0% higher, 12 years later, compared to that of unthinned plots. Average volume growth of individual trees in heavily thinned plots was 39.8~46.8% higher, 5 years later, and 23.0~52.0% higher, 12 years later, compared to unthinned plots. The maximum volume and biomass per unit area were shown in unthinned plot; the volume and biomass 5 and 12 years later after thinning were $133m^3/ha$ (51 kg/ha) and $344m^3/ha$ (132 kg/ha), respectivily. The significant difference appeared in crown width, volume, and biomass depending on thinning intensity. No dead trees occurred in heavily thinned plots for 12 years after thinning, while mortality rate in unthinned plots was 27.9~37.8%. As a result of analyzing annual increment using cores to determine the timing of second thinning, it suggested that second thinning be suitable around 10 years after first thinning.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.327-338
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• 2014

Relationship between growth rate and wood quality was investigated by physical and mechanical properties with Quercus rubra (24 years old) from five different origin of apricot. In greenwood moisture content, sapwood had higher moisture content than heartwood, and there was difference among different origin of apricot. There were different specific gravity of wood among different origin of apricot. Compared with higher growth rate with higher specific gravity in sapwood, opposite trend was observed in heartwood. There were difference in shrinkage based on origin of apricot, and higher growth rate wood had higher shrinkage and T/R ratio. Compression Young's modulus, bending strength, bending Young's modulus, and compact strength was difference among different origin of apricot. Higher growth rate wood had higher tensile strength, and also there was difference amont different origin of apricot. In hardness, 3 different directions had all difference among different origin of apricot, and higher growth rate wood showed higher hardness than others. Based on overall physical and/or mechanical properties and growth rate, apricot from Bancroft was best quality in current.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.150-164
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• 2022

This study was conducted to provide basic information for the development of silvicultural guidelines and manuals. This was achieved through analysis of tree and stand characteristics according to the first and second thinning in Korean white pine plantations. Data were collected from permanent plots installed at Korean white pine plantations according to thinning intensity, and residual tree and stand variables, including diameter at breast height (DBH), volume, and mortality at age 19-43, were analyzed using data repeatedly collected in 4-5 measurements by experiments. According to one-way variance of analysis, tree DBH and volume were significantly different according to thinning intensity (p<0.05). DBH distribution was skewed to the left side over time as thinning intensity was heavier. Thus, tree DBH values were larger in heavy thinning plots with increased age. The periodic annual increment (PAI) of DBH was higher with heavier thinning intensity and fewer years after thinning. The PAI range by thinning intensity was 0.48-0.95 cm/year at age 19-24. In addition, the PAI increased in heavy thinning plots after the second thinning; The PAI range by thinning intensity was 0.29-0.67 cm/year after the second thinning at age 37-42. The PAI of tree volume differed according to thinning intensity, and the PAI value did not decrease obviously, in contrast to the pattern of the DBH PAI. Stand volume was generally higher in high-density stands, and the PAI of stand volume was high in unthinned and light thinning plots. Mortality was highest in unthinned plots, and the differences in mortality according to thinning intensity increased over time. Consequently, the growth of DBH and tree volume was lower as stand density increased, but this growth was facilitated with appropriate first and second thinning operations.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.536-542
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• 2015

This study was examined for the growth response of tree diameter and volume to thinning treatments from different thinning intensities using three long-term thinning trials for Japanese Evergreen Oak (Quercus acuta Thunb.) stands in Wando island, Korea. After thinning in 1999, annual tree growth of diameter and volume was highest in heavy thinned stands for individual tree and this growth pattern of thinning response showed similar tendency to the individual tree growth response in light thinned stands. By increasing diameter growth, the value of H/D ratio (HDR) as an indicator of stem form was properly decreased and improved up to 80%. Although there is significant growth response of basal area in both heavily and lightly thinned stands, the growth potential both of heavily and lightly thinned stands in total stand volume is not likely to reach at the level of unthinned stands because of basal area growth loss associated with both light and heavy thinnings.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.210-220
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• 2019

Population growth and the increase of energy consumption due to civilization caused global warming. Temperature on the Earth rose about $0.7^{\circ}C$ for the last 100 years, the rate is accelerated since 2000. Temperature is a factor, which determines physiological action, growth and development, survival, etc. of the plant together with light intensity and precipitation. Therefore, it is expected that global warming would affect broadly geographic distribution of the plant as well as structure and function ecosystem. In order to understand the effect of global warming on the ecosystem, a study about the effect of temperature rise on germination and growth in the plant is required necessarily. This study was carried out to investigate the effects of experimental warming on the germination and growth of two oak species(Quercus mongolica and Q. serrata) in temperature gradient chamber(TGC). This study was conducted in control, medium warming treatment($+1.7^{\circ}C$; Tm), and high warming treatment ($+3.2^{\circ}C$; Th) conditions. The final germination percentage, mean germination time and germination rate of two oak species increased by the warming treatment, and the increase in Q. serrata was higher than that in Q. mongolica. Root collar diameter, seedling height, leaf dry weight, stem dry weight, root dry weight, and total biomass were the highest in Tm treatment. Butthey were not significantly different in the Th treatment. In the Th treatment, Q. serrata had significantly higher H/D ratio, S/R ratio, and low root mass ratio (RMR) compared with control plot. Q. mongolica had lower RMR and higher S/R ratio in the Tm and Th treatments compared with control plot. Therefore, growth of Q. mongolica are expected to be more vulnerable to warming than that of Q. serrata. The main findings of this study, species-specific responses to experimental warming, could be applied to predict ecosystem changes from global warming. From the result of this study, we could deduce that temperature rise would increase germination of Q. serrata and Q. mongolica and consequently contribute to increase establishment rate in the early growth stage of the plants. But we have to consider diverse variables to understand properly the effects that global warming influences germination in natural condition. Treatment of global warming in the medium level increased the growth and the biomass of both Q. serrata and Q. mongolica. But the result of treatment in the high level showed different aspects. In particular, Q. mongolica, which grows in cooler zones of higher elevation on mountains or northward in latitude, responded more sensitively. Synthesized the results mentioned above, continuous global warming would function in stable establishment of both plants unfavorably. Compared the responses of both sample plants on temperature rise, Q. serrata increased germination rate more than Q. mongolica and Q. mongolica responded more sensitively than Q. serrata in biomass allocation with the increase of temperature. It was estimated that these results would due to a difference of microclimate originated from the spatial distribution of both plants.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.316-321
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• 2016

This study developed an eco-block for grass growth using the expanded vermiculites that absorb bacteria selected considering for the high pH and dry environments and plant growth. For the developed eco-block, a fundamental properties including compressive strength gain and water absorption and ecology characteristics were tested. The selected bacteria was Bacillus alcalophilus a nd Rhodoblastus acidophilus and had high concentration of $10^9cell/mL$. The expanded vermiculite that was used for shelter of bacteria was added by 7.5% and 10% replacement of the natural aggregates by volume. The developed eco-block achieved the minimum requirements specified in SPS provision and significantly effective in reducing chemical Chemical Oxygen Demand(COD) concentration and enhancing the growth of fish and plant.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.266-278
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• 2012

The objective of this study was developing dynamic stand growth model to predict diameter at breast height (DBH) growth by thinning intensity and cycle for major tree species of South Korea. The yield table, one of static stand growth models, constructed by Korea Forest Service was employed to prepare dynamic stand growth models for 8 tree species. In the process of model development, the thinning type was designated to thinning from below and equations for predicting the DBH change after thinning by different intensities was generated. In addition, stand density (N/ha), age and site index were adopted as explanatory variables for DBH prediction model. Thereafter, using the model, DBH growth under various silvicuture through integrating such equations considering thinning intensities, and cycles. The dynamic stand growth model of DBH developed in this study can provide understanding of effectiveness in forest growth and growing stock when thinning practice is performed in forest. Furthermore, results of this study is also applicable to quantitatively assess the carbon storage sequestration capability.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.527-535
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• 2015

With results from previous Korean studies on forest thinning, we conducted a meta-analysis on the effect of thinning on diameter at breast height (DBH) growth and carbon (C) stocks (tree, litter layer, coarse woody debris (CWD), and soils) in Korean forests. Thinning increased the DBH growth and the C stocks in soils by 39.2% and 12.8%, respectively, while it decreased the C stocks in tree by 30.9%. In contrast, thinning had no significant effect on the C stocks in litter layer and CWD. The DBH growth and the C stocks in tree showed significant correlations with thinning intensity and recovery time. The C stocks in litter layer correlated with recovery time while those in CWD and soils did not show significant correlation neither with thinning intensity nor with recovery time. Regression models of the DBH growth and the C stocks in tree were developed to quantify the effect of thinning intensity and recovery time. An integration of the regression model of the tree C stock into forest carbon models is expected to be essential to quantify the effect of thinning on the C stocks in litter layer, CWD, and soils. We also suggested expansion of study species, long-term and frequent monitoring, and investigation on understory vegetation in order to elucidate changes in Korean forests following thinning practices.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.165-171
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• 2016

The objective of this study is to evaluate the compressive strength development and ecological characteristics of mortars using expanded vermiculite absorbing bacteria as a fundamental investigation to develop precast eco-concrete products. For bacterial growth under the high-alkalinity and high-dried environments within hardened mortars and for creating plant growth function to mortars, Bacillus alcalophilus and Rhodoblastus acidophilus were separated and cultured. The cultured bacteria were absorbed into expanded vermiculite selected for bacteria shelter. The expanded vermiculite absorbing bacteria was then added into mortar mixture as a volumetric replacement of fine aggregate. Test results showed that the developed technology is very effective in enhancing the plant growth onto the hardened mortars and reducing the COD and T-N concentration in raw water. The optimum replacement level of expanded vermiculite absorbing bacteria can be recommended to be less than 10% considering the compressive strength development and cost of mortars along with the ecological effectiveness.