• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.4
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• pp.247-254
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• 2003

This study was conducted to develop site index equations by main species grown in Gyunggi and Chungcheong provinces using environmental factors obtained from a digital forest site map. For this, 28 environmental factors were regressed on site index by species. Four to five environmental factors by species were selected as independent variables in the best site index equations (coefficients of determination greater than 0.91). For these site index equations, three evaluation statistics, mean difference, standard deviation of difference, and standard error of difference, were applied to the data set. Site index equations by species relationships developed in this study effectively estimate forest productivity in the study area. However, the site index equation of Larix leptolepis showed a larger than expected bias between the estimated and the measured site index. The reason is not clear in this situation, but might be because of the small sample set. It will be necessary, therefore, to conduct more studies to determine the exact reason. It is also expected that the site index equations with a few environmental factors as independent variables could provide valuable information about species well suited to given site conditions. Site index equations for other species should be developed to establish a rational policy about the selection of best species for site conditions.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.209-216
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• 2023

This study aimed to use national forest inventory data to develop a forest productivity index and yield prediction model of a Tilia amurensis stand. The site index displaying the forest productivity of the Tilia amurensis stand was developed as a Schumacher model, and the site index classification curve was generated from the model results; its distribution growth in Korea ranged from 8-16. The growth model using age as an independent variable for breast height and height diameter estimation was derived from the Chapman-Richards and Weibull model. The Fitness Indices of the estimation models were 0.32 and 0.11, respectively, which were generally low values, but the estimation-equation residuals were evenly distributed around 0, so we judged that there would be no issue in applying the equation. The stand basal area and site index of the Tilia amurensis stand had the greatest effect on the stand-volume change. These two factors were used to derive the Tilia amurensis stand yield model, and the model's determination coefficient was approximately 94%. After verifying the residual normality of the equation and autocorrelation of the growth factors in the yield model, no particular problems were observed. Finally, the growth and yield models of the Tilia amurensis stand were used to produce the makeshift stand yield table. According to this table, when the Tilia amurensis stand is 70 years old, the estimated stand-volume per hectare would be approximately 208 m³ . It is expected that these study results will be helpful for decision-making of Tilia amurensis stands management, which have high value as a forest resource for honey and timber.

• Journal of Construction Engineering and Project Management
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• v.4 no.1
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• pp.45-50
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• 2014

Productivity analysis is the most important and significant method for evaluating management and engineering performance during whole project stage. However, it is very difficult in developing qualitative index to construction industry comparing to other industries. Therefore, analytical hierarchy process (AHP) is one of the methods for overcoming these limitations by checking consistency index using duality comparison. In this study, it is scraped up an application plan and selection for innovative tools by analyzing survey results on tool users and site managers with respect to using Modified-AHP performance measurement method.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.126-135
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• 2015

This study was conducted to develop a large scale map of species-specific plantation sites based on selected environmental variables such as topography, soil, and climatic factors in Namwon city. Site index equations by tree species were first regressed to 27 environmental variables that could influence the productivity of forest sites using digital forest site maps, digital climate maps, and the 5th National Forest Inventory data. Site index equations by tree species were all evaluated to estimate site productivity using 4-5 environmental variables, and the models' reliability was confirmed based on evaluation statistics. The determination coefficients of site index equations by species ranged from 0.42 to 0.76. With the site index equations, the site conditions appropriate for productive sites by species were considered to assess spatial distribution of productive areas for each species. The final map for optimal plantation in Namwon city was produced based on both site index equations and site conditions appropriate for productive sites by each species using GIS technique. Field survey was conducted to evaluate the suitability of selected species on the map of species-specific plantation sites. Results showed that the plantation map provides relatively reasonable spatial distribution of productive areas for selected species. It was revealed, however, that the sites evaluated as 'not suitable' for any tree species should be revised and complemented with additional information, especially with the site conditions appropriate for productive sites by species of interest. The outcomes of this study are expected to provide information for making customized species-specific plantation maps.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.132-140
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• 2005

This study was conducted to develop regional site index equations for main tree species in Gangwon, Gyunggi-Chungcheong, Gyungsang, and Jeolla area of Korea, using environmental and soil factors obtained from a digital forest site map. Using the large data set obtained from the digital forest map, a total of 28 environmental and soil factors were regressed on site index by tree species for developing the best site index equations for each of the regions. The selected main tree species were Larix 1eptolepis, Pinus koraiensis, Pinus densiflora, Pinus thunbergii, and Quercus acutissima. Finally, four to five environmental and soil factors by species were chosen as independent variables in defining the best regional site index equations with the highest coefficients of determination $(R^2)$. For those site index equations, three evaluation statistics such as mean difference, standard deviation of difference and standard error of difference were applied to the data sets independently collected from fields within the region. According to the evaluation statistics, it was found that the regional site index equations by species developed in this study conformed well to the independent data set, having relatively low bias and variation. It was concluded that the regional site index equations by species had sufficient capability for the estimation of site productivity.

• Journal of agriculture & life science
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• v.43 no.4
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• pp.9-14
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• 2009

The purpose of this study was to estimate height growth pattern and to derive site index equation for Pinus densiflora grown at Mt. Osu region, Chungnam. A total of 21 repre - sentative trees from the established temporary plots around Boryeng and Cheongyang regions were destructively sampled to measure diameter, height, volume growth per 1-year interval by using of DTRS- 2000 measurement instrument. The Schnute growth function was select ed for height growth prediction using 181 height-age paired observations and derived anamorphic base age invariant site index curves (base index age 30 years). The fitted index and the asymptotic value of Schnute model indicated both 0.96 and 10.8 meter, respectively. The results suggested in this study could be very useful to understand the height growth pattern and productivity of the site quality on Pinus densiflora grown at Mt. Osu region, Chungnam.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.23-31
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• 2023

Predicting forest productivity is essential to evaluate sustainable forest management or to enhance forest ecosystem services. Ordinary least squares (OLS) and partial least squares (PLS) regression models were used to develop predictive models for forest productivity (site index) from the site characteristics and soil profile, along with soil physical and chemical properties, of 112 Quercus mongolica stands. The adjusted coefficients of determination (adjusted R²) in the regression models were higher for the site characteristics and soil profile of B horizon (R²=0.32) and of A horizon (R²=0.29) than for the soil physical and chemical properties of B horizon (R²=0.21) and A horizon (R²=0.09). The PLS models (R²=0.20-0.32) were better predictors of site index than the OLS models (R²=0.09-0.31). These results suggest that the regression models for Q. mongolica can be applied to predict the forest productivity, but new variables may need to be developed to enhance the explanatory power of regression models.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.34-36
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• 2003

In boreal conifers in China's Northeast area, maximum latewood density (MXD) of tree-ring varies in response to growing season temperature. Forest net productivity can be estimated using the Normalized-difference Vegetation Index (NDVI) calculated from satellite sensor data. MXD from the Mohe site in this area was compared with estimates of NPP for 1982-1999 produced by the NDVI model, which was established based on the relationship of leaf area index (LAI) and NDVI. The result shows that the MXD series correlated significantly with the NDVI model estimates series, suggesting that MXD appeared to be an appropriate index for productivity or canopy growth in region where forest productivity is strongly temperature-related.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.36-44
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• 2010

In order to rehabilitate forest sites damaged by wildfire via natural or artificial restoration, it is important to determine right tree species, which can acclimate to biogeoclimatic environment at the sites. The objectives of this study were to develop site index equation of different tree species for estimating forest productivity and to provide information on species selection for post-wildfire restoration. Site index equation was developed based on environmental information from wildfire damaged areas in Gangneung, Goseong, Donghae, and Samcheok, where were located in east coastal areas of South Korea. Despite the small numbers (4~5) of environmental variables used for the development of the site index equations, statistical analysis (e.g. mean difference, standard deviation of difference, and standard error of difference) showed relatively low bias and variation, suggesting that those equations can provide relatively high capability of estimation and practical applicability with high effectiveness. The small numbers of the variables enabled the model to be applied in a wide range of usages including determination of appropriate tree species for post-wildfire restoration. The estimation of forest site productivity showed the possibility of large distribution in east coastal region as the best site for Korean ash (Fraxinus rhynchophylla) and original oak (Quercus variabilis) that can be used for firebreak in the region. These results imply that damages by forest fire can be reduced significantly by replacing existing pure coniferous forests in the area with ones dominated by broad-leaved deciduous stands, which can play an important role as fire break and/or prevent a transition from surface fire to crown fire.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.1
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• pp.52-66
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• 2009

The increase of rice productivity, the decrease of rice demand, aging farmers, and the market-opening of rice along with the domestic and international conditions changes have been led to the increase of the abandoned rice paddy fields. Such abandoned rice paddy fields have been left in many areas and most of them have become wetlands. The purpose of this study is methodology of selection to the wetland for development in the abandoned rice paddy fields along with surroundings. The selection of habitat suitability index assessment study to conservation and restoration was done through hydrology, wild animals habitation, wetland vegetation, outside disturbance, and natural purification capacity assessment. In addition, the same method was applied to assessment items and standards for both the restoration site selection and the type of restoration. Both assessment items and standards were applied to the sites, drawn on the maps, and overlayer for the comprehensive map, and then the wetland suitability index was applied to the suitable site. The development technique was applied to 10 sites near the Banwol Stream watershed in Gunpo, Gyeonggi province. The selection of conservation, restoration, and the optimal sites can lead to not only the biodiveristy increase in agricultural or semi natural areas but also to the establishment of ecological networks in national level.