• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.72-80
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• 1995

Altitudinal effects on the accumulation of O layer were examined for deciduous broad-leaved forests in the experimental forest of Kangwon National University. There found a marked increased towards the higher altitudes in the thickness of O layer. These trends could be observed conspicuously on the F2 and H layers. The relation between thickness (X, cm) and dry weight (Y, $kg/m^2$) of O layer was approximated by linear regression equations;Y($kg/m^2$ = aX(cm). The values of coefficient "a" for the F2, H and F2+H layers were 0.43, 0.61 and 0.53, respectively. Bulk densities of the accumulated organic matter estimated nearly to be $45g/dm^2$ in F2 layer, $60g/dm^2$ in H layer and $55g/dm^2$ in F2+H layer. The amount of O layer ranged from 13ton/ha for the forest at 280m in altitude to 41ton/ha for the upper forest at 710m in altitude. Among these total amount of the O layer, F1, F2 and H layer occupied to be 5~10ton/ha, 5~11ton/ha and 13~40ton/ha, respectively.

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.255-258
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• 2020

Pine wilt disease (PWD) caused by pine wood nematode (PWN), Bursaphelenchus xylophilus, which is transmitted by Monochamus alternatus and M. saltuarius, is a serious threat to coniferous forests in the Northern Hemisphere, including Korea. The efficacy of abamectin and emamectin benzoate for preventing the PWD in the field and its effect on the vectors Monochamus alternatus and M. saltuarius (Coleoptera: Cerambycidae) were evaluated. An experimental plot was delimited, of which consists of Japanese red pine (Pinus densiflora) forest in South Korea, and trunk injection trials were made with abamectin and emamectin benzoate. Branches of each tree were collected, and are subsequently subjected to the analysis of residues for both nematicides. Results obtained in this study showed that abamectin and emamectin benzoate showed over 90% mortality at the recommended concentration after 6 days and 8 days, respectively. Consequently, it was found that both insecticides have a higher effect on the susceptibility and persistence of two vectors of PWD, M. alternatus and M. saltuarius feeding on branches of the trees, and its application by trunk injection is confirmed as an option for pine wilt disease management programs in Korea.

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.437-446
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• 1995

This study was carried out to estimate the Korean Pine stand structure such as coefficient of variation of mean DBH, number of trees and volume per ha by Weibull distribution for each age class from I to V, based on photo measurement and timber cursing in Kangwon National University Experimental Forests. The results were summarized as follows: 1) Coefficient of variation of mean DBH for each age class from I to V, which was obtained by converting DBH estimated from crown diameter by photo measurement into quadratic mean DBH, was estimated as 28.88%, 24.13%, 23.29%, 20.27%, and 18.79%, respectively. 2) Number of trees per ha of each age class by Weibull distribution was obtained as 2875, 2100, 1875, 800, and 325, respectively. 3) Volume per ha of each age class was estimated as $22.9m^3$, $66.8m^3$, $101.3m^3$, $209.6m^3$, and $266.8m^3$, respectively. 4) Therefore, aerial photographs will be helpful to estimate the stand structure effectively.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.254-262
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• 2012

The purposes of the research in related to FSC in JuJe experimental forests (JJEFs) is to make pre and post socio-economic comparisons and play an important role of FSC, and recognition change to FSC timbers and to make an analysis to consumers' needs. As the results of onsite survey in 2005, respondents show a high awareness of SFM and FSC in comparisons of 2004, and the JJEFs play a critical role to make SFM and FSC advertisement worldwide, such as consumers' satisfaction to SFM and FSC is high. Hence provision of JJEF information such as job creation and socio-economic impacts to stockholders could make their satisfaction improving. Most of respondents to the FSC of JJEF represent a positive rate while low awareness to FSC timber is represented. Therefore, necessary information about JJEF FSC with forest management, process and consumption pattern of FSC is required into citizens. The final results prove that FSC effects such as 1.3 billion won direct additional benefits in terms of socio-economic aspects including environmental benefits and job creation and economic effects are enough to offset 1.3 billion won additional costs.

• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.53-68
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• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• Journal of Forest and Environmental Science
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• v.10 no.1
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• pp.57-65
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• 1994

This study was carried out to clarify the sediment export by measuring suspended solids included in streamflow during the rainy season. The study area is located in Experimental Forests, Kangwon National University, where the forest road is under construction. For this purpose, the forest watershed with construction of forest road was compared with normal forest watershed in amount of rainfall and discharge, suspended solids and discharge, and the amount of rainfall and suspended solids. The results were shown as followings. 1. The relationship of discharge and the amount of rainfall was shown as Table 3 and Fig. 3. The delay time of peak point observed in hydrograph was changed by rainfall intensity and amount of previous rainfall. That is, when there was a rain on 12. Jun(more than 20mm/hour for hours), the peak point began three hours after the rainfall intensity over 20mm/hour, and showed $1514m^3/hour$ in automatic water level recorder. In case of the 8th of Aug.(maximum rainfall intensity: 40mm/hour), the peak point of discharge was $1246m^3/hour$ in the same time with maximum rainfall intensity. And on the 20th of Aug.(the maximum rainfall intensity: 17.2mm/hour), the peak point of discharge was $1245m^3/hour$ two hours after the maximum rainfall intensity. 2. On watershed under forest road construction, the relationship between discharge and suspended solids is that suspended solids was proportionately increased by raising discharge. That is, on the 12th of Jun, the maximum of discharge per hour was $1514m^3/hour$ and 1261mg/l of suspended solids was observed an hour after peak point of discharge. And in case of 8th and 20th Aug., each of peak points is $1246m^3/hour$ and $1245m^3/hour$ by measuring time. The maximums of suspended solids measured within two watersheds were examined in value of 4952mg/l and 472mg/l at the same time. 3. During the rainy season, the concentration of suspended solids was influenced by rainfall intensity and indicated especially curve-regressional increase in case of strong rainfall intensity. In each of watersheds, the maximums of suspended solids were 1261mg/l and 125mg/l, 4952mg/l and 44mg/l, and 472mg/l and 4mg/l by the order of rain(a), (b), and (c). Two watersheds showed a remarkable difference.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.524-531
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• 1996

The objective of this study was to determine the important factors affecting the early natural regeneration of Pinus densiflora S. et Z. Seed germination, survival and height growth of the pine seedlings were examined at four experimental plots of P. densiflora forests including forest roadside. Plots I and III were thinned in 1992, plot II was treated with hexazinone in 1993 after seed tree method was applied in 1982 and 1989. Seedlings emerged after thinning and the rate of their emergence depended on forest floor conditions. Seedling survival was related with light conditions, herbaceous vegetation, and degrees of rainfall. More seedlings emerged in forest hauling roads than within the forest because soil scarification due to logging provided better conditions for seed germination and seedling growth. Seed supply was enough, but germination rate was very low in the forest compared with that in the greenhouse because micro-environments such as organic layer and herbaceous plant acted as limiting factors. Weed control was needed for 4 to 5 years until seedlings grew upto about 50cm in height which was similar to that of herbaceous plants. But 10-40% coverage of herbaceous vegetation was needed to protect small seedlings from heavy rain. Forest works such as thinning and logging, over 40% of light were important factors to help the pine regeneration. However, over 70% coverage of herbaceous vegetation, and heavy rain inhibited rather survival and growth of pine seedlings.