• Korean Journal of Environment and Ecology
• /
• v.8 no.2
• /
• pp.154-159
• /
• 1995

The Chuwang valley-Kumunkwangi valley forest in Chuwangsan area was studied to investigate forest structure in relation to altitude and part of slope. Forty eight quadrats were set up in the valley forest along altitude of 470m to 780m and part of the slope. Density and basal area of trees in tree strata decreased as increasing elevation. With increasing elevation the importance values of Quercus mongolica, Fraxinus rhynchophylla increased, while those of Pinus densiflora, Lindera obtussiloba decreased. As going from lower part to upper part of the slope, the importance values of Quercus valiabilis and Lindera obtussiloba increased while those of Fraxius rhynchophylla, Acer mono decreased. Species diversity tended to decreased as going to upper parts of the slope. The range of similarity indices between elevation belts, and parts of the slope were 74.4~84.2% and 68.0~96.3%, respectively. According to importance value and cluster analysis, the studied valley forest was classified into three forest communities of Pinus densiflora-deciduous tree species community of lower part of slope, Pinus densiflora-Quercus variabilis community of middle and upper part of slope, Pinus densiflora community of the top area.

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.5
• /
• pp.597-606
• /
• 2019

Cellulose nanocrystals (CNCs) were successfully isolated from oil palm fronds (OPFs) using different concentrations of ammonium persulfate (APS), and their characteristics were analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, and thermogravimetric analysis (TGA). APS oxidation effectively isolated CNCs with rod-like morphology in nanometer scale. The dimensions of the CNCs decreased with increasing APS concentration. FTIR and XRD analyses revealed that all the CNCs showed crystals in the form of cellulose I without crystal transformation occurring during APS treatment. The relative crystallinity of the CNCs increased with increasing APS concentration, whereas their thermal stability decreased. An APS concentration of 2 M was found to be optimal for isolating the CNCs.

• Journal of Forest and Environmental Science
• /
• v.39 no.4
• /
• pp.246-253
• /
• 2023

Salix gracilistyla is widely distributed along riversides in Korea and very good for biomass production by SRC because of its excellent germination ability, but it is necessary to measure drying tolerance for cultivation. The drought tolerance of S. gracilistyla was tested using cuttings, and growth and physiological analysis were performed after irrigation was stopped. The growth inhibition of S. gracilistyla was observed from the day irrigation was stopped, and the soil moisture content decreased to less than 10% on the 25th day after irrigation was stopped. Over 50% of the seedlings turned brown 25 days after watering was stopped. The chlorophyll content of S. gracilistyla decreased dramatically after 25 days of stopping of irrigation. RWC values were unchanged until day 12 after irrigation was stopped but decreased rapidly until day 21, but there was a slightly decreasing trend after that. RWL levels increased slightly during irrigation stops. The proline content of plants subjected to drought stress was 0.91-2.63 mg/0.05 g, 2.75 times higher than that of the control treatment. The sugar content of the drought stress treatment group was 29.77 to 350.66 mg/0.05 g, which increased 12.24 times that of the control treatment. As a result of this study, S. gracilistyla was found to have a drought tolerance almost comparable to that of evergreen broad-leaved trees growing on the land. This study is expected to contribute to the resource utilization S. gracilistyla, a native willow tree of Korea, and the mass production of biomass by SRC.

• Journal of Korean Society of Forest Science
• /
• v.100 no.3
• /
• pp.417-422
• /
• 2011

In general, forest tending work contributes to preventing landslides by enhancing forest health. In order to quantify beneficial effects of forest tending, landslide occurrences in forest tending area and those in non-forest tending area were compared and analyzed. The landslide had been hit hard in Inje and Pyeongchang county, Gangwon province, following Typhoon 'Bilis' on July 15, 2006. Data on forest tending of Pinus koraiensis and Larix kaempferi stands were acquired from the Inje National Forest Station, North regional forest service. The rate of landslide occurrence was increased sharply just after forest tending work and was decreased as time goes by. The analysis also found that the change in landslide frequency was slight by age class in the non-forest tending area, while it decreased as age class increased in the forest tending area.

• Journal of People, Plants, and Environment
• /
• v.22 no.3
• /
• pp.309-319
• /
• 2019

This study was conducted to investigate the effects of watching a virtual reality (VR) forest video on stress reduction in adults. Experiments were performed in an artificial climate chamber where temperature, humidity and illumination were controlled. To cause stress in subjects, the subjects were asked to multiply two digit numbers by one digit numbers for two minutes. The subjects then watched a VR forest video for five minutes. During the experiment, the heart rate variability (HRV) and heart rate (HR) of subjects were continuously measured for evaluating their physiological state. After measuring the baseline and watching a VR forest video, their psychological state was evaluated using the profile of mood state (POMS), semantic differential (SD) method, and positive affect and negative affect schedule (PANAS). The results of physiological evaluation after watching a VR forest video showed a decrease in the stress index and HR, an increase in the activity of the parasympathetic nervous system, and the standard deviation of normal to normal RR intervals (SDNN). The results of psychological assessment confirmed that watching a VR forest video induced "comfort", "natural", and "soothed" feelings in subjects. In addition, watching a VR forest video decreased "tension-anxiety (T-A)", "depression-dejection (D)", "anger-hostility (A-H)", "fatigue (F)", "total mood disturbance (TMD)", and increased "vigor (V)" compared to the base line, and decreased "negative affect" and increased "positive affect." These results indicate that watching a VR forest video decreases adults' stress index, stabilizes physiological state, and has a positive impact on psychological state. The findings of this study can serve as a basis for providing forest welfare services to people in the blind spots of forest welfare, and can lay a foundation for the adoption of VR, one of the technologies of the fourth industrial revolution in forestry.

• Journal of the Korea Furniture Society
• /
• v.20 no.3
• /
• pp.198-204
• /
• 2009

Less used small diameter logs of black locust were heated at $250^{\circ}C$ for improving utilization. The volatile compounds emitted by the heated logs were analyzed. Their effect of formaldehyde absorption was evaluated with PB. Ester and acid compounds were dominant in content. Especially, methyl acetate and acetic acid showed the highest contents. The total content of aromatic compounds decreased as heating time increased. Amoung ketone compounds, The contents of 2-propanone, 2-pentanone, 3-petanone, 3-hexanone and cyclopentenone decreased with the increase of heating time, but the others did not. The contents of the chemicals, furfural and 3-pentanol, increased with heating time, while that of 2-methyl butanal decreased. It was hard to say that formaldehyde was absorbed by the heated black locust samples. Some decorative goods were designed with the heated logs.

• Journal of Forest and Environmental Science
• /
• v.32 no.3
• /
• pp.270-279
• /
• 2016

This study explained vertical distributions and growth environments for woody vegetation. It had been degenerated by long-term volcanic activity of Sakurajima; vegetation and thicknesses of tephra layers and forest soils were investigated at 5 sites (250-700 m in altitude) with different altitudes localized at the northwestern-northern flanks of Sakurajima in Kagoshima Prefecture. The results in 2015 were compared with the vertical distribution of woody vegetation in 1963, when the volcanic activity of Sakurajima was relatively moderate. Thus, we investigated temporal changes in the vertical distribution of woody vegetation owing to volcanic activity over about 50 years (1963-2015). We indicated altitude decreased, the number of woody vegetation, number of species, sum of cross-sectional area of tree diameter at breast height, Fisher-Williams's diversity index ${\alpha}$, and forest soil thickness increased. However, these values were found to be degenerated when compared to climax forest values, and succession was incomplete. It seems that because the woody vegetation of the flank was affected by volcanic activity for a long time, exposing them to severe growth environments, areas with lower altitudes became distant from the craters of Sakurajima, thereby weakening the effect of volcanic activity in these areas at lower altitudes. a at the same altitudes over about 50 years (1963-2015) decreased by about 31-72%, and the sum of the cross-sectional area in tree diameter at breast heights decreased by about 14-62%. Thus, comparative growth environments for woody vegetation in 2015 were more severe than that of 1963, with respect to tephra layer thickness. In addition, for vegetation succession in the flank of Sakurajima, vegetation restoration should be promoted through the introduction of artificial woody plants covered by symbiotic microorganisms or organic materials.

• Journal of the Korean Applied Science and Technology
• /
• v.24 no.4
• /
• pp.416-426
• /
• 2007

Polypropylene (PP) composites with wood flour/wax/coupling agent were manufactured by melt compounding and injection molding. The influence of wood flour(WF), wax, and coupling agent on the mechanical and thermal properties of the composites was investigated. The addition of wood flour to neat PP has the higher tensile modulus and strength compared with neat PP. The presence of wax also improved the tensile modulus. At the same loading of PP and WF, the addition of coupling agent highly decreased the tensile modulus, and increased the tensile strength. From thermogravimetric analysis (TGA), the addition of wax improved the thermal stability of the composites in the later stages of degradation. The presence of MAPP and wood flour in turn decreased thermal stabilities of composites. From differential scanning calorimetry analysis (DSC), neither the loading of wax. nor the presence of MAPP has shown significant effect on the thermal transition of composites.

• Journal of Forest and Environmental Science
• /
• v.34 no.6
• /
• pp.472-480
• /
• 2018

This study was conducted to estimate carbon storage in Quercus mongolica stands based on stand age class, and to provide basic data on the carbon balance of broad-leaved forests of Korea. The research was conducted at the experimental forest of Kangwon National University, Hongcheon-gun County, Gangwon-do Province, Korea. Three plots were set up in each of three Q. mongolica forest stands (III, V, and VII) to estimate the amount of carbon stored in Q. mongolica aboveground vegetation, coarse woody debris (CWD), organic layer, mineral soil, and litterfall. The carbon storage of the aboveground vegetation increased with an increase in stand age, while the carbon storage ratio of stems decreased. The carbon storage of the organic layer, CWD, and litterfall did not show any significant differences among age classes. In addition, the carbon concentration and storage in the forest soils decreased with depth, and there were no differences among age classes for any soil horizon. Finally, the total carbon storage in the III, V, and VII stands of Q. mongolica were 132.2, 241.1, and $374.4Mg\;C\;ha^{-1}$, respectively. In order to predict and effectively manage forest carbon dynamics in Korea, further study on deciduous forests with other tree species in different regions will be needed.

• Journal of Naturopathy
• /
• v.10 no.1
• /
• pp.33-41
• /
• 2021

Purposes: We studied whether forest bathing is effective in improving the stress of the human body. Therefore, we investigated changes in pulse rate, stress index, and autonomic nervous system after 2 hours of forest bathing on Jeju Samdasu Forest Methods : The study was conducted before and after forest bathing through heart rate variability and questionnaire. Results: After forest bathing, the average pulse rate of the experimental group was significantly increased. The stress index significantly decreased in the post-test in the experimental group. The cumulative stress, sympathetic activity (LF), parasympathetic activity (HF) change, and LF/HF ratio were slightly different from those of post-test in the experimental group, but were not statistically significant. In the survey of job stress average index and state characteristic anxiety index through questionnaire, it decreased significantly after forest bathing (p<.001). Conclusions: The Samdasu forest bathing has been proven effective in enhancing pulse and reducing stress, so it is evaluated that forest bathing is effective in promoting health.