• Journal of Korean Society of Forest Science
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• v.76 no.2
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• pp.145-160
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• 1987

To evaluate damage status and necessities of repair works on the forest-side erosion control structures constructed from 1966 to 1986 in Korea, developmental procedures of erosion control structures from the standard unit-cost tables established by the Forestry Administration every year, existing counter-measures for disaster erosion control system administrated by the government organization and existing status of each structure at constructed site were investigated and analyzed integrally. About 10-15% of the constructed forest erosion control structures were required to be repaired as a result of the investigation. It is actually incapable of repairing the damaged forest erosion control structures caused by excessive run-off and floodings under the existing forest-side erosion control systems. Therefore, it is necessary to put regularly repair erosion control system that will be secured by national budgetary pre-allocation system. Especially, it is also necessary to frame a new system that repair erosion control works by national budget (central government) should be possible for any scale of damages in case of the erosion control projects for the disaster counter-measures. The results of this research could be adopted as important policy data for erosion control policy-making in forest-side in Korea.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.237-245
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• 1991

Artificial acid rain (pH 3.0, 4.0 and 5.0) was treated on thd seeds of 5 coniferous species to examine its effects on germination and seedling growth. Artificial acid rain was prepared by diluting sulfuric acid with ground water and ground water(pH 6.5) was used as control. Artificial acid rain was sprayed to seeded pots three times per week. About 5mm of artificial acid rain was treated each time from early April to early October, 1990. Germination, seedling establishment and seedling growth were measured and compared among the treatments. The results were summarized as follows ; 1. Germination, seedling establishment rate of Larix leptolepis and Picea koraiensis were highest on the pH 5.0 plot whereeas those of Abies holophylla and Cryptomeria japonica were highest on the control plot, and those of Abies koreana showed the highest value on the pH 3.0 plot. 2. The differences in seedling height growth of Larix leptolepis was signif- icant at 1% level among the treatment levels of acid rain, whereas those of other species were not significant, Height of Larix leptolepis, Abies koreana and Picea koraiensis were highest on the pH 4.0 plot, and that of Abies holuphylla and Cryptomeria japonica were highest on the pH 5.0 plot. 3. Seedling dry weight of Larix leptolepis and Abies holophylla differed significantly at 1% level among the treatments, but those of other species did not differ. Highest seedling dry weight of Larix leptolepis and Abies koreana were observed on the pH 4.0 plot, and that of Abies holophylla and Cryptomeria japonica did on the pH 3.0 plot, and that of Picea koraiensis did on the control plot. 4. With decrease of pH value of artificial acid rain, the number of injured needle and injured individual tended to be increased, obviously. 5. The differences of soil acidity were highly significant among the treatments for all species.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.303-309
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• 1992

This study eras carried out to investigate the ecological changes on the plant community at erosion controlled area in Yoju-gun, Kyonggi-do. The results of the study were as follows : 1. The depth of organic matters in the soil profile from 4 to 14 years was estimated to be $Y_{(cm)}=0.436X_{(yr)}-0.931$(r=0.978), and 02 layer was $Y_{(cm)}=0.339_{(yr)}-0.931$ (r=0.954). 2. On upper plant layer. Alnus spp. was decreased, on an average, 32% of relative coverage, 12.4% of relative density and 16.8% of relative frequency in each plot for 3 years, as this area was damaged by Agelastica coerulea Baly for 2-3 years. 3. On upper plant layer, relative coverage of Pinus spp. was increased after 6, 7 years in erosion controlled area and was taked the highest plant (more then 40%) from 10 to 14 years. 4. On lower plant layer, relative density of Quercus ssp. (these species has not been planted and sown on erosin controlling) was increased all the plot. 5. The increase of the whole crown projection area was estimated to be $Y_{(m^2)}=18.020X_{(yr)}+18.834$(r=0.954) 6. The biomass was estimated to be 14.88t/ha on elapsed 6 years, 22.84t/ha on 8 years, 35.08t/ha on 10 years, 47.80t/ha on 12 years, 58.13t/ha on 14 years.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.42-47
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• 2016

To examine the natural regeneration in the natural mixed-broadleaved forest, flowering, fruiting, seed-fall, and seed viabilities of Acer pseudosieboldianum (Ap) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2015. The flower of Ap consisted many male and bisexual flowers on the corymb. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of Ap might be pollinated by Apis mellifera, Andrenidae spp. and Syrphinae spp. Ap had some mechanism to prevent from self pollination with heterodichogamy. Mean annual seedfall of Ap was 70,780 ea/ha (ranged 310~234,840 ea/ha). Annual seedfall of Ap varied severely, and the maximum was about 760 times the minimum. Annual seed production of Ap might be to a normal distribution. Rates of damaged or decayed seeds are highest 59.3%, and those of sound seeds are 23.9%, Those of undeveloped and empty seeds are 9.2% and 7.6%, respectively. The most important factors influencing sound seed production might be the density and activities of insect pollinators and sucking pest in the flowerwing period, middle-late May. Successful regeneration of Ap might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of deciduous hardwoods, further study on the characteristics of flowering and fruiting, pre- and post-dispersal seed predation, and annual variation on these factor should be needed.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.153-158
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• 2014

To examine the natural regeneration in the natural mixed-broadlived forest, flowering, fruiting, seed-fall, and seed viabilities of Acer ukurunduense Trautv. & C.A. Mey. (AU) were investigated in Mt. Jungwang, Gangwon-do, from 2009 to 2013. The flower of AU consisited many male and bisexual flowers on the raceme (unusual panicle) and the arrangement of two sex morphs are differed for each inflorescence. Flowering dates are differed between sex morph in the same inflorescence. Stamens are stop growing and disappeared after pollinated pistil begin to grow in bisexual flowers, and male flowers have vestial pistil. The flowers of AU might be pollinated by Apis mellifera, Thyris fenestrella seoulensis, Cerambycidae sp., Andrenidae sp. and Ctenophora sp., and had some mechanism to prevent feom self pollination. The number of flower buds per inflorescence is 189 on June 8, and that of young samaras per inflorescence is 41.2 on June 21. At last ripened samaras per inflorescence is reduced 33.4 on September 5. Mean annual seedfall of AU was 6,720 ea/ha (ranged 670~17,930). Rates of sound seeds are highest 43.2%, and those of damaged or decayed seeds are 41.8%,. Those of undeveloped and empty seeds are 10.2% and 4.8%, respectively. Successful regeneration of AU might be in masting year and on the gap sites with proper conditions to germinate and grow. To understand the natural regeneration of the species, Genus Acer, further study on the fruiting habit, pre- and post-dispersal seed viability, and annual variation on these factor should be needed.

• Journal of the Korean association of regional geographers
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• v.14 no.6
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• pp.709-717
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• 2008

This study is to analyze environmental problems which have caused by changes of the population and agriculture in North Korea. Main results of the research are following. First, Population of the North Korea shows lower increase ratio less than 2% growth from 1970's to middle of 1990's. This is interpreted by food shortages. Second, population distribution by provinces represented that northern and eastern part of the North Korea were comparatively lower and other western areas were higher. Third, Food situation of the North Korea was relatively better in 1970's, but, 1990's was the worst in the way. Fourth, on the agricultural productivity according to each province, western areas possessing more plains were more higher than mountainous areas of the northern and eastern parts of North Korea. Fifth, Growth ratio of food production and population have grown very steadily until 1990's, but the increase ratio of population exceeded food productivity after 1990's. Sixth, Cropland reclamation for improving these situation have caused deforestation and environmental problems and especially eastern and northern areas became more serious. For the solving these problems of North Korea, it is necessary to get the help of South Korea and international societies with efforts by itself.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.34-40
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• 2017

In recent years, global warming has caused abnormal weather phenomena. Unusually cold climates have occurred all around the world, including cold waves in the Northeastern United States, Beijing, China, Southern India, and Pakistan, as well as floods in Chile, Kazakhstan, and Vietnam. China has been experiencing a nationwide heat wave annually since the year 2013, especially in the southern region. In this study, we used Landsat 8 OLI TIRS sensor images from four periods to analyze the characteristics of abnormal high temperature phenomena in Cixi-si, China. Land cover classification was performed using 10 bands of satellite imagery, and the surface temperature was extracted using the 10th thermal band. The results of the land cover classification of the fourth period show the changes of the time series quantitatively. The results of the surface temperature calculation provided both the average overall temperature and the average temperature of individual items. The temperature was found to be highest for buildings, followed by grassland, forest, agricultural land, water systems, and tidal flats in the same period.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.420-427
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• 2013

This study was conducted to analyze growth characteristics and adaptability of poplar clones under the treatment of liquid pig manure. The average of survival rate was 33% better at control than the treatment under age of 5 years. But, tree height and DBH growth were higher at the treatment than control. Populus euramericana 'Eco28' showed the highest survival rate (97.9%) under the treatment. P. euramericana 'Eco28' and P. deltoides hybrid 'Dorskamp' could be selected as superior clones for height and DBH growth under the liquid pig manure treatment. The above-ground biomass production was also investigated when the poplar clones were 5 years old. The aboveground biomass under the liquid pig manure treatment was, on average. 52.6 ton/ha, which was 80% higher than control (29.1 ton/ha). P. euramericana 'Eco28' (73.6 ton/ha) and P. deltoides hybrid 'Dorskamp' (71.1 ton/ha) showed superior biomass production than other clones at the treatment of liquid pig manure. Based on survival, growth and demage traits, the adaptability of poplar clones to liquid pig manure treatment was estimated. P. deltoides hybrid 'Dorskamp' and P. euramericana 'Eco28' showed better adaptability to the treatment. P. nigra ${\times}$ P. maximowiczii '62-10' and P. koreana ${\times}$ P. nigra var. italic 'Suwon' were identified as poor adaptability clones.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.291-297
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• 2019

Since Metcalfa pruinosa was first reported in Koera, it has continually caused damage to sweet persimmon orchard in southern part of Korea. Metcafa pruinosa exist not only in farmland but also in forest areas, and are difficult to control due to the influx of individuals from near forest. M. pruinosa has been occurred in orchard and its surroundings because of various host range. Thus, it has been difficult to decide spatial range and control time for efficient management. In this study, occurrence and dispersal pattern of M. pruinosa in persimmon orchard were surveyed using clear sticky traps, and spatial patterns were analyzed with SADIE(Spatial Analysis by Distance IndicEs), based on location information at sticky traps. Spatial association between survey time was also analyzed to identify when the spatial pattern changed. In sweet persimmon orchard, M. pruinosa mainly dispersed in mid to late May, when the first instar hatches, and in August, emerging season of adult. The first instar nymphs hatched in mid-May were randomly distributed in orchard, but distribution was changed to aggregative pattern after dispersed surroundings of orchard. Adults showed random distribution pattern after immigration to orchard again. These tendency was also observed in density change at orchard and its surroundings, and matched to actual density of M. pruinosa in sweet persimmon trees.

• Journal of Korean Society of Forest Science
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• v.70 no.1
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• pp.38-44
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• 1985

These surveys were conducted for the purpose of fundamental data of environmental ecology to save the damage of the fieldmice at the National Park of Mt. Jiri, shown especially in the 5 areas of Jang-dang, U-pyung, Jung-san-ri, Sea-seok and Dae-sung area from October, 1983 to September, 1984 during which the fieldmice were very active. The results were summarized as follows; 1) Fieldmice observed were 3 species: Clethrionomys rufocanus regulus, Apodemus speciosus peninsulae and Apodemus agrarius coreae. 2) Types of fieldmice hole were of 5 types; around the roots of trees, at fallen trees, between rocks and the ground, on the surface of the slope ground, on the surface of the ground. The holes were found mostly around the trees (33.2%). 3) Inhabitant ratio was the highest at Dae-sung area (22.6%). Breeding was the most active in July. 4) Females found in July at Sea-seok area were the most in the number (6.6%). Males found at U-pyung area were the most in July in the number, at Sea-seok area in May, at Dae-sung area in July (5.4%). 5) The weight ranged between 20.3g and 57.4g. Clethrionomys rufocanus regulus was the heaviest (37.8g), Apodemus speciosus peninsulae the next and Apodemus agrarius coreae the highest. The heaviest were those found at Dae-sung area.