• Journal of Korean Society of Forest Science
• /
• v.96 no.2
• /
• pp.189-196
• /
• 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
• /
• v.27 no.1
• /
• pp.47-54
• /
• 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
• /
• v.88 no.4
• /
• pp.446-453
• /
• 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 Forest and Environmental Science
• /
• v.34 no.3
• /
• pp.235-241
• /
• 2018

This study was conducted to find out the growth pattern of Pinus koraiensis plantation over 34 years, focusing on DBH, height, basal area and allometric change. Total increment (TI), mean annual increment (MAI) and correlation coefficient were calculated and compared with stand and dominants. Total increment and mean annual increment of both DBH and height of dominants were bigger than those of stand. The difference was apparently shown bigger in DBH than height. Unlike DBH and height the total increment and mean annual increment of basal area per hectare of dominants were distinctively smaller than those of stand. Furthermore MAI of dominant was increasing until age 42, while MAI of stand increased at early ages and then gradually decreased after culmination like MAIs of DBH and height. MAIs of basal area of dead trees at each measurement tended to increase until early age (18 years in this study), while it reached a peak and gradually decrease after that (21 years in this study). Correlation coefficient between DBH and height tended to decrease as both dominant and stand age and the difference between dominant and stand was not clearly shown over the measurement period. Correlation coefficients between DBH and crown width tended to decrease as the trees age and correlation coefficients of dominant were clearly shown smaller than that of stand. Correlation coefficients of height and crown width also was found to be similar to correlation coefficients between DBH and crown. Meanwhile correlation coefficient of height and crown width dropped more radically than coefficient of DBH and crown width as the trees age.

• Journal of Korean Society of Forest Science
• /
• v.96 no.2
• /
• pp.138-144
• /
• 2007

This study was undertaken to compare the biomass of Abies koreana growing at two sites. A $10{\times}10m$ plot was established in each site of a natural stand in Mt. Jiri and a plantation in Gyeongsan nursery. Five trees of A. koreana were randomly selected in each site. The following traits were investigated from each tree : height, basal diameter, age, weight of stem, branches, and needles as above-ground traits and weight of total roots, horizontal roots, and vertical roots as below-ground traits. In Gyeongsan nursery, age of sample trees was negatively correlated with both height and weight of total stem, while height was highly correlated with weight of horizontal roots. There was high correlation between the basal diameter and weight of total stem, and between the basal diameter and weight of roots. In Mt. Jiri stand, most of the above-ground traits except age were significantly correlated with the below-ground traits. The linear regression equation between the cross section area of base (X) and the weight of total stem (Y) in Gyeongsan nursery was Y=12.66X-12.92, and correlation was significant ($R^2=0.89$). The linear regression equation between the cross section area of base(X) and the weight of total branches (Y) in Mt. Jiri stand was Y=25.51X+6.00, and correlation was highly significant ($R^2=1.0$).

• Journal of Forest and Environmental Science
• /
• v.34 no.2
• /
• pp.119-125
• /
• 2018

The tropical forests in developing countries are faced with the problem of illegal exploitation of trees. However, dearth of empirical means of expressing the dimensions, structure, quality and quantity of a removed tree has imped conviction of offenders. This study aimed at developing a model that can effectively estimate individual tree basal area (BA) from stump diameter (Ds) for Tectona grandis stands in Omo Forest Reserve, Nigeria, for timber valuation in case of illegal felling. Thirty-six $25m{\times}25m$ temporary sample plots (TSPs) were laid randomly in six age strata; 26, 23, 22, 16, 14, and 12 years specifically. BA, Ds and diameter at breast height were measured in all living T. grandis trees within the 36 TSPs. Least square method was used to convert the counted stumps into harvested stem cross-sectional areas. Six basal area models were fitted and evaluated. The BA-Ds relationship was best described by power model which gave least values of Root mean square error (0.0048), prediction error sum of squares (0.0325) and Akaike information criterion (-15391) with a high adjusted coefficient of determination (0.921). This study revealed that basal area estimation was realistic even when the only information available was stump diameter. The power model was validated using independent data obtained from additional plots and was found to be appropriate for estimating the basal area of Tectona grandis stands in Omo Forest Reserve, Nigeria.

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

• Journal of Ecology and Environment
• /
• v.30 no.3
• /
• pp.251-255
• /
• 2007

Self-thinning was measured in Salix communities on Bam Island in Seoul at various age stages. $D^2H$ was used to estimate tree biomass, where D is stem diameter at breast height or 10 cm height for plants with height <1.5 m, and H is height. A log-log plot of density versus $D^2H$ and correlation analysis indicated a significant relationship between density and biomass with equation 'log $D^2H$ = -1.27 log N + 7.06'. This indicates that self-thinning affects biomass in the Salix community with -1.27 as the thinning coefficient. If we assume a thinning exponent -3/2, then the allometric coefficient of the equation, log w = a log $D^2H$ + b, is 1.18. This is much higher than that for any other species studied in Korea. There were statistically significant relationships between age and density and between age and basal area and these relationships suggest guidelines for transplantation of willows and for the assessment of Salix community restoration projects in riverine wetlands based on standard density, basal area, and age. The results of this study may also increase understanding of succession processes in Salix community restoration in riverine wetlands.

• Journal of Korean Society of Forest Science
• /
• v.80 no.2
• /
• pp.187-192
• /
• 1991

This study was carried out to estimate the stand volume for Japanese larch(Larix leptolepis) by Strand sampling method. The data collected for this study were based on the 380 sample plots from the field survey, which were distributed in the major part of Korea(Kyeongi, Kangweon, Chungbuk, Chungnam, Chunbuk and Kyeongbuki), and the plotless sampling instrument such as dendrometer, spiegel relascope and tele-relascope were used. The procedure for this study is summarized briefly as follows : 1. There were not only significant differences between volume estimation by Strand sampling method and that by plot survey method, and the relationship was y=bx, where b approached nearly 1. Therefore, the stand volume of Japanese larch could by estimated by Strand sampling method. 2. The value measured by three different plotless sampling instruments did not showed any significant differences between instruments and observers, density and instruments, and ground slope and instruments. 3. With the stand volume, basal area height showed the highest correlation and stand form height, average height, basal area per ha correlated with the volume in thier orders. 4. The best fitted equation of stand volume estimation with basal area height by relascope was as follow. log V=-0.0375+0.8910 log GH-1.5946 1/GH Stand volume table also was obtained using the above estimeated equation. 5. The relationship between estimated value and actual value was Y=bx, where b was nearly 1. The correlation coefficient was very high and the percentage of estimated error was 4.5%.

• Journal of Forest and Environmental Science
• /
• v.35 no.1
• /
• pp.1-5
• /
• 2019

Species diversity is one of the most important indices that used to evaluate the sustainability of forest communities. In the present study, three variables including number of individuals (frequency of species), basal area and volume of tree species were compared to estimate tree species diversity in broadleaves forests of Iran. Based on systematic random design, 30 plots (circle plot, $1000m^2$) was selected. Type of species, number of species, DBH and height of trees were measured. Simpson (1-D), Hill ($N_2$), Shannon-Wiener (H'), Mc Arthur ($N_1$), Smith-Wilson ($E_{var}$) and Margalef ($R_1$) indices used to estimate tree species diversity. Species diversity was calculated in each plot. ANOVA test showed that there was a significant difference between of three variables used for estimation of species diversity. Number of trees variable has more precision than basal area and volume variables to estimate of species diversity. But Duncan test revealed that there were significant difference between of basal area and volume variables with number of trees. Therefore, basal area and volume variables were selected as more suitable variables in order to estimate of biodiversity indices in northern forests of Iran.