• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.9-14
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• 2024

Quantitative evaluation of nutrient status and stoichiometry on the forest floor is a good indicator of litter quality in various vegetation types. This study was conducted to determine the effects of vegetation type on the nutrient concentration and stoichiometry of forest floors at a regional scale. Forest floor samples were collected from four vegetation types of evergreen coniferous forests including Cryptomeria japonica, Chamaecyparis obtusa, evergreen broadleaf, and bamboo spp. forests in southern Korea. The dry weight of the forest floor was higher in the C. japonica and C. obtusa forests than in the evergreen broadleaf and bamboo forests. The mean carbon (C) concentrations of the forest floor were highest in the broadleaf forest, followed by the bamboo forest, C. japonica and C. obtusa forests. Mean nitrogen (N) and phosphorous (P) concentrations in the the coniferous forests were lower than those in the broadleaf and bamboo forests. The mean C:N ratio was the highest in C. obtusa forest (118±25), followed by C. japonica (66±6), evergreen broadleaf (41±1), and bamboo (30±1) forests. However, C:P and N:P ratios were lower in the coniferous forests than in the broadleaf forest indicating that the stoichiometry of the forest floor varies across vegetation types. The C, N, and P stocks on the forest floor were higher in the C. obtusa forest than in the broadleaf or bamboo forests. These results highlight that vegetation type-dependent stoichiometric ratio is an useful indicator for understanding interspecific difference in quality and quantity of the forest floor.

• Journal of Forest and Environmental Science
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• v.33 no.4
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• pp.330-341
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• 2017

Tropical forests play a key role for functioning of the planet and maintenance of life. These forests support more than half of the world's species, serve as regulators of global and regional climate, act as carbon sinks and provide valuable ecosystem services. Forest floor biomass and litterfall dynamics was measured in different sites influenced by fire in a seasonally dry tropical forest of Bhoramdeo wildlife sanctuary of Chhattisgarh, India. The forest floor biomass was collected randomly placed quadrats while the litterfall measured by placing stone-block lined denuded quadrat technique. The seasonal mean total forest floor biomass across the fire regimes varied from $2.00-3.65t\;ha^{-1}$. The total litterfall of the study sites varied from $4.75-7.56t\;ha^{-1}\;yr^{-1}$. Annual turnover of litter varied from 70-74% and the turnover time between 1.35-1.43 years. Monthly pattern of forest floor biomass indicated that partially decayed litter, wood litter and total forest floor were differed significantly. The seasonal variation showed that leaf fall differed significantly in winter season only among the fire regimes while the wood litter was found non significant in all the season. This study shows that significant variation among the site due to the forest fire. Decomposition is one of the ecological processes critical to the functioning of forest ecosystems. The decomposing wood serves as a saving account of nutrients and organic materials in the forest floor. Across the site, high fire zone was facing much of the deleterious effects on forest floor biomass and litter production. Control on such type of wildfire and anthropogenic ignition could allow the natural recovery processes to enhance biological diversity. Chronic disturbances do not provide time for ecosystem recovery; it needs to be reduced for ecosystem health and maintaining of the high floral and faunal biodiversity.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.426-432
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• 2013

Fire resistance and impact sound insulation tests were performed for a floor assembly, of which stiffness was reinforced by shortening the span of floor joists by installing glulam beam additionally in the middle or one thirds of the original span, and which an additional ceiling component was installed apart from floor structure. By applying the isolated ceiling, timber framed floor showed 1 hour of fire resistance even in case that dead load was increased by considering cement mortar layer for radiant floor heating. Insulation performance against light and heavy impact sound was improved significantly by applying the sound absorbing layer of big mass and high elasticity in addition to the stiffness improvement and isolated ceiling.

• Journal of the Korean Wood Science and Technology
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• v.51 no.5
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• pp.419-430
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• 2023

In this study, the floor impact sound insulation performance of Korean domestic Cross-Laminated Timber (CLT) slabs was evaluated according to their joint types, species and thicknesses in laboratory experiments. The sound insulation performance of the CLT has not been investigated before, thus, this study was conducted to quantify basic data on floor impact sound insulation performance of CLT slabs. 5-ply and 150 mm thick CLT panels made of 2 species, Larix kaempferi and Pinus densiflora, were used for the study. The CLT panels were assembled by 3 types of inter-panel joints to form floor slabs: spline, butt and half-lap. And the 150 mm thick Larix CLT slabs were stacked to the thicknesses of 300 mm and 450 mm. The heavy-weight floor impact sound insulation performance of the 150 mm CLT slabs were evaluated to be 70 dB for the Larix slabs and 71.6 dB for the Pinus slabs, and the light-weight floor impact sound insulation performance, 78.3 dB and 79.6 dB, respectively. No significant difference in the sound insulation performance was found between the slabs of the 2 species or among the 3 types of joints. The reduction of 1 dB in the heavy-weight floor impact sound and 1.6 dB in the light-weight floor impact sound per 30 mm increase in thickness were confirmed through the experiments. This study can be viewed as the basic research for the evaluation of floor impact sound insulation performance of CLT.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.325-328
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• 2007

We discuss the Normalized Difference Vegetation Index (NDVI) of the forest canopy and floor separately based on airborne spectral reflectance measurements and simultaneous airborne land surface images acquired around Yakutsk, Siberia in 2000. The aerial land surface images were visually classified into four forest types: no-green canopy and snow floor (Type-1), green canopy and snow floor (Type-2), no-green canopy and no-snow floor (Type-3), and green canopy and no-snow floor (Type-4). The mean NDVI was calculated for these four types. Although Type-2 had green canopy, the NDVI was rather small (0.17) because of high reflection from the snow cover on the floor. Type-3, which had no green canopy, indicated considerably large NDVI (0.45) due to the greenness of the floor. Type-4 had the largest NDVI (0.75) because of the greenness of both the canopy and floor. These results reveal that the NDVI depends considerably on forest floor greenness and snow cover in addition to canopy greenness.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.181-187
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• 2014

Forest floor is one of most distinctive features of forest ecosystem, which provides plants and soil microbes with nutrients, and controls hydrologic condition within the floor by intercepting water during a rainfall event and evaporates back into the atmosphere. In this study rainfall interception loss by decomposed forest floor of a deciduous forest has been experimentally estimated using rainfall simulation experiments. Litter-decomposing fungi were incubated on deciduous forest floor samples for the experiment purposes. On a deciduous floor, a $4.22mm{\cdot}kg^{-1}{\cdot}m^2$ of rain was intercepted immediately before rain ceased. Minimum values of interception loss ranged from 1.62 to $2.41mm{\cdot}kg^{-1}{\cdot}m^2$, with an average of $1.87mm{\cdot}kg^{-1}{\cdot}m^2$. Mann-Whitney test showed that decomposing fungi on the forest floor influenced on rainfall interception capacity.

• The Korean Journal of Ecology
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• v.23 no.2
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• pp.83-88
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• 2000

When interpreting change over time in forest ecosystems, distinguishing the effects of forest succession from the effects of environmental stress can be difficult. The result may be a simplistic interpretation. citing a specific successional or environmental cause of forest change when both types may be occurring. We present two case studies of changes in the forest floor in northern hardwoods. First, the belief that 50% of soil organic matter is lost in the first 20 years after logging was based on a study comparing northern hardwood stands of different ages. We resampled a series of 13 such stands after an interval of 15 years, and found that the young stands were not, in fact. losing organic matter as rapidly as predicted from the original chronosequence study. The pattern of higher organic matter content in the forest floors of older stands compared to young stands could be equally well explained by changes in logging practices over the last century as by the aging of the stand. The observed pattern of forest floor organic matter as a function of stand age was previously interpreted as a successional pattern, ignoring changes in treatment history. In the second case study, observed losses of base cations from the forest floor were attributed to cation depletion caused by acid rain and declining calcium deposition. We found that young stands were gaining base cations in the forest floor; losses of base cations were restricted to older stands. Differences in litter chemistry in stands of different ages may explain some of the pattern in cation gains and losses. In this case, the contribution of successional processes to cation loss had been overlooked in favor of environmental stress as the dominant mechanism behind the observed changes. Studies of environmental stress use repeated measures over time. but often don't consider stand age as a factor. Studies of successional change often assume that environmental factors remain constant. We were able to consider both forest succession and external factors because we repeatedly sampled stands of different ages.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.431-444
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• 2012

Constituents of timber framed floor affect the insulation performance against impact sound significantly. Among them, installation of massive sound absorbing layer and reinforcement of stiffness of timber floor have been considered as major factors that improve the insulation performance against impact sound. Researches on evaluating the effect of floor constitutions have been carried out through the field measurements for timber framed buildings in Korea. It is concluded that the impact sound pressure level at the relatively lower frequency governs the overall insulation performance, and can be improved by the installation of sound absorbing layer and reinforcement of floor stiffness. Especially, the insulation performance against heavy impact sound was improved significantly when the massive cement mortar layer for floor heating system was installed and the stiffness was reinforced by shortening the joist span using additional beam at the mid-position of original span.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.391-399
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• 1994

This study was carried out to investigate the water storage charateristics of surface soil by different forest floor conditions and to measure water storage capacity of forest Land at the Yeungnam University forest in Yongjang-ri, Nenam-myoen, Kyongju-gun, Kyongsangbuk-do. The study was conducted for 4 months, from June to September, 1993. The results were summarized as follows ; 1. Infiltration capacity of surface soil for each. forest floor condition was in the order : Oak forest>Oak forest removed $A_o$ layer>Pine forest removed $A_o$ layer>Pine forest>Bare land>Grasses. 2. The absolute values of infiltration capacity were increased as the rain intensity increased, while the order of infiltration capacity for each floor condition was not changed. 3. Infiltration capacity was highly correlated with surface soil hardness and todal pores. 4. Infiltration formula based on the Horton's could be estimated at each forest floor condition. 5. The model for water storage capacity of forest land expressed by infiltration capacity was estimated using total pores and soil hardness. This study indicates water storage capacity of different forest floor conditions depends on infiltration capacity. Using these formula, it was possible to calculate and estimate water storage capacity of forest land. Therefore, the result of this study will be helpful to increase water storage capacity of forest land and to manage water resources effectively.