Fertilizers are commonly applied to improve the productivity and quality of bamboo. However, the nutrient responses of bamboo components after regular fertilization are not fully understood. This study was carried out to determine the effects of regular fertilization on the nutrient distribution of biomass components (i.e., culms, branches, leaves, roots, rhizomes) in a Moso bamboo stand in southern Korea. The study site was fertilized regularly for approximately 30 years to produce edible bamboo shoots. A total of 20 bamboo plants (10 fertilized and 10 unfertilized) were cut to measure the nutrient (C, N, P, K, Ca, Mg) concentrations of each bamboo component. Belowground roots and rhizomes were sampled at a 30-cm soil depth. The N, P, and K concentrations and stocks of aboveground biomass components were increased by regular fertilization, whereas the C, Ca, and Mg stocks were attributed to culm densities. The nutrient stocks of belowground roots were significantly lower in the fertilized plots than those in the unfertilized plots, except for the P stocks. The results indicate that regular fertilization could be a key factor to maintaining bamboo shoot productivity because of the increased responses of the nutrient concentration and stocks of bamboo components.

The purpose of this study was to develop site index for Pinus thunbergii in southern region of Korea. Collected data to dominant, or co-dominant 59 trees measures the age, and height was conducted to using five growth models. To verify the accuracy of estimates, models were developed using 40% of the total data and validation data was the remaining 60%. For the verification of the selected model, the fitness index, the root mean square error, and the bias were used. The main results showed that the Gompertz model provided the best fit index, bias, and root mean square error with 0.618, -0.281, 2.266, respectively. The index age of site index derived from Gompertz model choose 50 years, which refer to cutting age for Pinus thunbergii. The site index for Pinus thunbergii in southern region of Korea was range from 16 to 24. The results obtained from this study may provide useful information about the forest management for Pinus thunbergii in southern region of Korea.

A total of 74 Japanese black pine (Pinus thunbergii Parl.) and red pine (P. densiflora S. et Z.) trees were destructively sampled in southern Korea, which is severely affected by pine wilt disease (PWD). Species-specific allometric equations were developed to estimate the biomass, carbon (C) and nitrogen (N) content of the tree components (i.e., stem wood, stem bark, branches, needles and roots) based on the diameter at breast height (DBH) and stem diameter at 20 cm aboveground (D20). The C concentrations of the various tree components were not correlated with DBH (P > 0.05), except for the C concentration in the stem bark (r = -0.29, P < 0.05) of the black pine and the branches (r = 0.40, P < 0.05) of the red pine. However, the N concentrations in the stem wood (r = -0.53, P < 0.05), stem bark (r = -0.37, P < 0.05) and branches (r = -0.40, P < 0.05) of the black pine were negatively correlated with DBH. The mean C concentrations of the tree components were not significantly different between the black pine and red pine, except for the stem bark, whereas the mean N concentrations were significantly lower in the black pine than in the red pine, except for the stem bark. The allometric equations developed for the biomass, C and N content for all the tree components were significant (P < 0.05). The adjusted coefficient of determination (adj. R 2 ) of the DBH allometric equations ranged from 0.66 to 0.97, while the coefficients for the D20 equations were between 0.66 and 0.95. Black pines consistently exhibited more biomass, C and N content in the tree components compared with the red pines with similar DBH or D20. These results suggest that the accuracy of estimates for biomass, C and N stocks in black pine and red pine forests could be improved by specific allometric equations for PWD-disturbed forests.

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