• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.189-196
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• 2007

Allometry, basal area equations, and volume equations were developed with various tree measurement variables for the major species, Quercus mongolica and Quercus variabilis, in Korean natural hardwood forests. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, crown width) and relative size (relative diameter, relative height) as well as competition measures (competition index, crown class, exposed crown area, percent exposed crown area, live crown ratio). For tree volume equations, the combined-variable and Schumacher models were fitted with DBH, total height and crown width for both species.

• Journal of Forest and Environmental Science
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• v.27 no.1
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• pp.47-54
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• 2011

Allometry and basal area equations were developed with various tree measurement variables for the major species; Quercus variabilis, Quercus mongolica, Pinus koraiensis and Larix leptolepis in Korea. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, and crown width), relative size (relative diameter and relative height) as well as competition measures (competition index, crown class, and live crown ratio).

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.446-453
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• 1999

In this study, the effects of stand planting density on parameters of stand height and basal area growth models were investigated. We used the Korf equation as the base model in estimating the parameters of the growth models for cryptomeria plantation forest stands. Then, in order to investigate the effects of the change in plantation density on the parameter estimates, the "extra sums of square" principle, which provided a reasonable statistical procedure for a performance test, was used. The results of the test coincide with the understandings that stand height growth is not affected significantly by the planting density and the growth curves of stand basal area approaches a common asymptote regardless of the stand density for a given site. However, the shapes of the basal area growth curves were affected significantly by the planting density. Based on the results of the test, we developed a basal area growth model to account for the effects of initial planting density in cryptomeria plantation forest stands.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.365-377
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• 1997

Much of the Cumberland Plateau of Tennessee, USA is in mixed hardwoods for which there are no applicable growth and yield predictors. Use of site index as a variable in growth and yield prediction models is limited in most stands because their history is not known and many may not be even-aged. Landtypes may offer an alternative to site index for these mixed stands because they were designed to include land of about equal productivity. To determine vegetation by landtype, dependency between landtype and detailed forest type was tested with Chi-square. Differences in productivity among landtypes were tested by employing regression analyses and analysis of variance(ANOVA). Basal area growth was fitted to the nonlinear models developed by Moser and Hall(1969). Basal area growth and volume growth were also predicted as a function of initial total basal area and initial volume with linear regression by landtype and by landtype class. Differences in basal area growth and volume growth by landtype were tested with ANOVA. Dependency between site class and landtype was tested with Chi-square. Vegetation types seem to be related to landtypes in the study area although the validity of the test is questionable because of a high proportion of sparsely occupied cells. No statistically significant differences in productivity among landtypes were found in this study.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.40-49
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• 1998

This study aimed to provide a strategy for selecting an adequate combination of growth intervals(i.e. times between age $T_1$ and age $T_2$) to be used to improve the reality of the growth equation through obtaining better precision of parameter estimates. Variety of growth functions were fitted to the data and one equation which best fitted the data was chosen for the analysis. A modified Schumacher projection equation, selected as a best equation, that included dummy variables representing locality as a predictor variable was fitted for basal area and height equations with nonoverlapping growth interval and all possible growth interval data sets of Douglas-fir(Pseudotsuga menziesii Mirb.Franco). The data were measured in all parts of the South Island of New Zealand. It was found that the precision of parameter estimates was increased in both basal area and height equations by using data set which contained a range of measurement intervals from short to long term.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.25-31
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• 2011

This study was conducted to develop the growth model for diameter at breast height (DBH) and basal area (BA) of Larix leptolepis stands grown in eastern mountain areas, Jeollabuk-do and to enhance the precision of the models by adding regional and climatal factors, such as altitude, mean annual rainfall, and mean annual temperature. In results, it was analyzed that Schumacher polymorphic equation might be the best model to estimate DBH and BA growth. In case of the DBH growth model, precision was improved by adding altitude and mean annual rainfall. Moreover, in case of the BA growth model, precision was improved by adding mean annual rainfall. Meanwhile, it would be necessary for more precise model to add various factors, such as stand density, mortality, thinning ratio, and edaphic status along with regional and climatal factors.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.19-24
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• 2001

14 kinds of perennial flower sods, including 10 Korean native wild perennial flowers such as Lychnis cognata, Achillea sibirica, Sedum spectabile, Sedum takesimense etc. were made with basal sheets of nonwoven fabric or jute fabric. Growth of plants planted on bark was better than that of planted on soil of open area. The plants planted on bark also showed difference in growth rate by the kinds of used basal sheets. In general, the growth of plants was good when nonwoven fabric was used as basal sheet instead of jute fabric. When jute fabric was used as basal sheet, It was severely decayed during growth period resulting in great decreasing of root sticking capacity to basal sheet. It was shown that the procumbent plants such as Tymus quinquecostatus, Ixeris stolonifera, Sedum oryzifolium, Sedum polystichoides having lower plant height and better ground coverage ability compared with upright plants such as Sedum spectabile and Aster glehni were more suitable for floral sod production.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.463-469
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• 2000

Douglas-fir (Pseudotsuga menziesd Mirb. Franco) is highly regarded as a commercial timber species throughout the world in part due to its fast growth relative to many other species. In this study, basal area per hectare equation for Douglas-fir plantations in Southland of New Zealand has been developed based on medium measurement cycles of permanent sample plots data set. The function was developed using the algebraic difference equation method, and various sigmoid-shaped projection equations were used. Parameter estimation was obtained by non-linear routine of the SAS. As a result, of the functions tested a variant of the Schumacher polymorphic function including site index and thinning term as predictor variables showed the higher precision of the fitting. The results indicate that site index is positively correlated with basal area growth. And the thinning term was found to be useful to increase precision of the model.

• Journal of Korean Society of Forest Science
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• v.97 no.4
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• pp.368-373
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• 2008

The objectives of this study were to validate existing growth models of Pinus densiflora and Larix leptolepis grown in Chonbuk regions, and to examine suitability of models to different regions using spatially varied data set. In the valuating model predicted of Pinus densiflora, except to DBH growth model, basal area and height prediction models were biased to fit to different region. And in the valuating predicted height, basal area and DBH model of Larix leptolepis, they were adequate to new data set acquired from different region. Therefore, existing prediction models, except DBH model, of Pinus densiflora have the limitation of practicality that could not be suitable for application to different region. However, owing to high compatibility shown predicted DBH, basal area and height models of Larix leptolepis, they will be adequate to use as the prediction models where data are available around eastern mountain areas of Jeollabukdo.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.634-644
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• 2000

Sterba's theory that stem number maintaining maximum basal area per ha is maximum stem number of a stand, had been applied to data from 103 temporary plots in even-aged Pinus densiflora stands in Kangwon province, Korea and a maximum stem number and mortality model was prepared. DBH growth model which estimates dbh with the independent variables of stem number per ha and dominant height shows the good statistical performance, and explains well differences in dbh growth that would be caused by stem number per ha and dominant height. Basal area model derived from dbh growth model also explains well differences in basal area according to stem number per ha and dominant height. The maximum stem number curve, which is derived from stem number per ha at maximum basal area for dominant height and dbh, represents well the upper range of stem number per ha observed. And maximum stand density index derived from the maximum stem number model for dbh could be used for the index of maximum potential density of a stand. The maximum stem number model and maximum stand density index in this study were not based on stand data with maximum density but based on the temporary data from stands with various density. This maximum stem number model can be applied to the estimation of mortality and maximum potential volume.