• Journal of the Korean Wood Science and Technology
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• v.13 no.1
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• pp.19-62
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• 1985

This study was performed to investigate: (i) the bending processing properties of silk worm oak (Quercus acutissima Carr.) and Korean red pine (Pinus densiflora S. et Z.) by boiling and steaming treatments; (ii) the effects of interrelated factors - sapwood and heartwood, annual ring placement, softening temperature and time, moisture content. and wood defects on bending processing properties; (iii) the changing rates of bending radii after release from a tension strap, and (iv) the improving methods of bending process by treatment with chemicals. The size of specimens tested was $15{\times}15{\times}350mm$ for boiling and steaming treatments and $5{\times}10{\times}200mm$ for treatments with chemicals. The specimens were green for boiling treatments and dried to 15 percent for steaming treatments. The specimens for treatments with chemicals were soaked in saturated urea solution, 35 percent formaldehyde solution, 25 percent polyethylene glycol -400 solution, and 25 percent ammonium hydroxide solution for 5 days and immediately followed the bending process, respectively. The results obtained were as follows: 1. The internal temperature of silk worm oak and Korean red pine by boiling and steaming time was raised slowly to $30^{\circ}C$ but rapidly from $30^{\circ}C$ to $80-90^{\circ}C$ and then slowly from $80-90^{\circ}C$ to $100^{\circ}C$. 2. The softening time required to the final temperature was directly proportional to the thickness of specimen. The time required from $25^{\circ}C$ to $100^{\circ}C$ for 15mm-squared specimen was 9.6-11.2 minutes in silk worm oak and 7.6-8.1 minutes in Korean red pine. 3. The moisture content (M.C.) of specimen by steaming time was increased rapidly first 4 minutes in the both species, and moderately from 4 to 20 minutes and then slowly and constantly in silk worm oak, and moderately from 4 to 15 minutes and then slowly and constantly in Korean red pine. The M.C. of 15mm-squared specimen in 50 minutes of steaming was increased to 18.0 percent in the oak and 22.4 percent in the pine from the initial conditioned M.C. of 15 percent The rate of moisture adsorption measured was therefore faster in the pine than in the oak. 4. The mechanical properties of the both species were decreased significantly with the increase of boiling rime. The decrement by the boiling treatment for 60 minutes was measured to 36.6-45.0 percent in compressive strength, 12.5-17.5 percent in tensile strength, 31.6-40.9 percent in modulus of rupture, and 23.3-34.6 percent in modulus of elasticity. 5. The minimum bending radius (M.B.R.) of sapwood and heartwood was 60-80 mm and 90 mm in silk worm oak, and 260 - 300 mm and 280 - 300 mm in Korean red pine, respectively. Therefore, the both species showed better bending processing properties in sapwood than in heartwood. 6. The M.B.R. of edge-grained and flat-grained specimen in suk worm oak was 60-80 mm, but the M.B.R. in Korean red pine was 240-280 mm and 260-360 mm, respectively. Comparing the M.B.R. of edge-grained with flat-grained specimen, in the pine the edge-grained showed better bending processing property than the flat-grained. 7. The bending processing properties of the both species were improved by the rising of softening temperature from $40^{\circ}C$ to $100^{\circ}C$. The minimum softening temperature for bending was $90^{\circ}C$ in silk worm oak and $80^{\circ}C$ in Korean red pine, and the dependency of softening temperature for bending was therefore higher in the oak than in the pine. 8. The bending processing properties of the both species were improved by the increase of softening time as well as temperature, but even after the internal temperature of specimen reaching to the final temperature, somewhat prolonged softening was required to obtain the best plastic conditions. The minimum softening time for bending of 15 mm-squared silk worm oak and Korean red pine specimen was 15 and 10 minutes in the boiling treatment, and 30 and 20 minutes in the steaming treatment, respectively. 9. The optimum M.C. for bending of silk worm oak was 20 percent, and the M.C. above fiber saturation point rather degraded the bending processing property, whereas the optimum M.C. of Korean red pine needed to be above 30 percent. 10. The bending works in the optimum conditions obtained as seen in Table 24 showed that the M.B.R. of silk worm oak and Korean red pine was 80 mm and 240 mm in the boiling treatment, and 50 mm and 280 mm in the steaming treatment, respectively. Therefore, the bending processing property of the oak was better in the steaming than in the boiling treatment, but that of the pine better in the boiling than in the steaming treatment. 11. In the bending without a tension strap, the radio r/t of the minimum bending radius t to the thickness t of silk worm oak and Korean red pine specimen amounted to 16.0 and 21.3 in the boiling treatment, and 17.3 and 24.0 in the steaming treatment, respectively. But in the bending with a tension strap, the r/t of the oak and the pine specimen decreased to 5.3 and 16.0 in t he boiling treatment, and 3.3 and 18.7 in the steaming treatment, respectively. Therefore, the bending processing properties of the both species were significantly improved by the strap. 12. The effect of pin knot on the degradation of bending processing property was very severe in silk worm oak by side, e.g. 90 percent of the oak specimens with pin knot on the concave side were ruptured when bent to a 100 mm radius but only 10 percent of the other specimens with pin knot on the convex side were ruptured. 13. The changing rate in the bending radius of specimen bent to a 300 mm radius after 30 days of exposure to room temperature conditions was measured to 4.0-10.3 percent in the boiling treatment and 13,0-15.0 percent in the steaming treatment. Therefore, the degree of spring back after release was higher in the steaming than in the boiling treatment. And the changing rate of moisture-proofing treated specimen by expoxy resin coating was only -1.0.0 percent. 14. Formaldehyde, 35 percent solution, and 25 percent polyethylene glycol-400 solution found no effect on the plasticization of the both species, but saturated urea solution and 25 percent ammonium hydroxide solution found significant effect in comparison to non-treated specimen. But the effect of the treatment with chemicals alone was inferior to that of the steaming treatment, and the steaming treatment after the treatment with chemicals improved 10-24 percent over the bending processing property of steam-bent specimen. 15. Three plasticity coefficients - load-strain coefficient, strain coefficient, and energy coefficient - were evaluated to be appropriate for the index of bending processing property because the coefficients had highly significant correlation with the bending radius. The fitness of the coefficients as the index was good at load-strain coefficient, energy coefficient, and strain coefficient, in order.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.49-59
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• 1981

In order to elucidate the process of plant succession of the Japanese red pine forests caused by pine gall midge, Thecodoplosis japonensis, in the area of Chungbuk and Kyongbuk, 12 study plots, 4 plots from each three districts, were set up. Districts A (Cheongwon)not attacked by this insect, as the check, District B(Gumi) in which the insect outbreak occured 5 years ago, and District C(Yeongdong)in which the insect outbreak occured 10 years ago, were sampled. The surveyed were some environmental factors, the number of woody plants, relative density, relative dominance values, species composition of plots by layer(upper, middle and ground), importance values, species diversity, similarity and dissimilarity index, etc. The results obtained are summarized as follows: The accumulation of litter on the ground was increased with the lengthening the insect damage duration. Through the crown opening and litter accumulation, the light intensity, temperature condition and soil moisture and nutrient content might be altered. According to the changes of species composition were forced. In general, the Genus Quercus, as a compensation species, has sprung up. The relative importance values for Q.aliena, Q.serrata, and Q.variabilis were significantly increased in the insect infested forests. 2. the stand structure and species composition of the insect attacked forest about 5 years later after the outbreak become complex and diverse. However, since this time, the simplicity of these regards become restored up to 10 years after the outbreak. 3. As the synthetic analysis of plant succession process, the relative values calculated from the relative density and the relative dominance values shown the dominant status of Genus Quercus in the heavily damaged forests. In addition, Genus Rhododendron and Genus Lespedeza with higher frequency become the ground vegetation components. They were gradually increased along the time elapsing after the insect out-break. 4. The differences in connection with the soil moisture contents, the organic matter contents which might give some influences to the vegetation change were hardly recognizable statistically among the studied plots by three district groups. We estimated that the annual mean precipitation and the annual mean temperature did not operated any meaningful effects on the vegetation alteration among plots between districts.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.718-732
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• 2013

The purpose of this study was to provide data for the basic research to found the effective conservation and management plan for the Geumdangsil Pine Forest of Yecheon designated as Natural Monument No. 469. Furthermore, this paper suggest efficient sustainable forest preservation and using. In order to achieve the sustainable forest preservation, this study was to analyse topography, land use, tree growth, soil environment, forest usage and forest management, etc. According to analysis the results, the site area is located in the flatlands where is from 130 to 140 m above sea level. The around forest was transformed into agricultural land. The 565 individuals of Pinus densiflora grows in the forest, whereas, 25 trees was cut down or died. There are signs of 25 stumps. The most of 565 trees' diameter at breast height(DBH) was centerized between 30 cm and 50 cm, moreover, the average life expectancy of trees were 85.4 years. The oldest age of tree was estimated to be 200 years. The Sample trees of rate of branch growth is from 4.3 cm to 5.1 cm per year. The middle branch which is more vigorous growth grow 24.2 cm for 3 years. Moreover, the result of soil physico-chemical properties analysis of 7 plots, 4 categories which is soil organic matter, total nitrogen, available phosphoric acid, specific electrical conductance was generally good, however, the 2 categories which is soil pH, exchangeable cation needed improvement. Currently, the site was not pressured by facilities and usage, however, there might be threaten by agriculture such as encroaching on forest. Therefore, there should establish comprehensive ecosystem management such as facility management, visitors management and operation management In this paper considered 4 fields that is ecosystem management, facility management, visitors management and operation management for sustainable management.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.280-292
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• 2017

Hail is not a frequently occurring weather event, and there are even fewer reports of hail damages to forest stands. Since the 2000s, an increase in hail incidence has been documented in Europe and the United States. In Korea, severe hails occurred in Jeollanam-do province on May 31 and in Gyeongsangbuk-do province on June 1, 2017. Hail size was ranged from 0.5 to 5.0 cm in diameter in Jeollanam-do, and from 1.5 to 3.0 cm in Gyeongsangbuk-do. This study was aimed to analyze the hail damages to forests by species and topography based on damage-categorized maps created by using drones and aerial photographs, and to analyze relationships of the damages with meteorological factors. The total damaged forest area was 1,163.1ha in Jeollanam-do, and 2,942.3ha in Gyeongsangbuk-do. Among the 'severe' damaged area 326.7ha, 91% was distributed in Jeollanam-do, and concentrated in the city of Hwasun which covers 57.2% of the total 'severe' damaged area. The most heavily damaged species was Korean red pine(Pinus densiflora S. & Z.) followed by P. rigida. Most broad-leaved trees species including oaks were recovered without any dead trees found. Liliodendron tulipifera was the most severely damaged in terms of the rate of 'severe' degree individuals which are needed to be checked whether they will die or be recovered. Cause of the death of pines was considered as the combination of physical damage caused by the hail and long-lasting drought with high air temperature that occurred before and after the hail event. No pathogens and insects were found which might have affected to tree deaths. We suggested a dieback mechanism of the pine trees damaged by hail and drought.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.49-56
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• 2000

This study was designed to investigate the adsorption of heavy metal ions by untreated bark according to the treatment conditions of aqueous solution. The effect of temperature and pH of aqueous solution, particle size of bark, addition of light metal ions on the adsorption was examined, and the competition in adsorption among heavy metal ions was also evaluated. te The adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased with increasing themperature of solution from $-5^{\circ}C$ to $10^{\circ}C$ however, it was relatively constant at temperatures between $10^{\circ}C$ and $55^{\circ}C$. The adsorption ratio of $Cr^{6+}$ increased continuously with increasing the temperature of solution. The maximum adsorption ratio of $Cu^{2+}$, $Zn^{2+}$, and $Pb^{2+}$ was noted at pHs ranged 6 to 7; however, the adsorption ratio declined sharply on either sides of the optimum. The adsorption ratio of $Cr^{6+}$ decreased continuously with increasing the pH of solution. The adsorption ratio increased as decreasing the particle size of bark, and there was little differences in adsorption tendency between pine and oak bark. By the addition of $Ca^{2+}$ or $Mg^{2+}$(10~25 ppm), the adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased. An increase of the adsorption ratio was higher in oak bark than in pine bark. However, the adsorption ratio of $Pb^{2+}$ and $Cr^{6+}$ was not affected by the addition of light metal ions. As the mixed solution of 2 or 3 kinds of heavy metal ions($Cu^{2+}$, $Zn^{2+}$, $Pb^{2+}$) was treated with the untreated bark, the adsorption of $Zn^{2+}$ decreased considerably because of the competitive adsorption among heavy metal ions. Also the adsorption of $Cu^{2+}$ was more and less reduced. However the adsorption of $Pb^{2+}$ was not affected by the presence of other heavy metal ions.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.678-688
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• 2021

This study was conducted to provide growth characteristics and stand information in preparation for natural regeneration method and silvicultural treatment of seed tree method in Korean red pine stands by using the field inventoried data 18 years after the seed tree regeneration method in 2001 and analyzing the stand and sapling characteristics. The study area was located in the Research Forest of Kangwon National University, Chuncheon-si, Gangwon-do. In November 2018, we collected tree measurement factors, such as diameter at breast height (DBH), height, crown class, stem quality, tree age, and annual height increment on the established plots. We calculated the basal area, volume, height-diameter ratio (HD ratio), and additional stand density variables such as the relative density and %stocking to analyze the managed stands. The number of mother trees was 58 trees/ha, with a 17.7% stocking level, whereas the number of saplings was 2,330 trees/ha, with a 79.0% stocking level. In germination, the age distribution of saplings ranged from 2001 to 2007, with most belonging to 15-16 years. The development condition of saplings was 10 cm in DBH and 8 m in height. DBH and height were higher as the crown class is more dominant, and this difference was statistically significant in the analysis of variance and Duncan's multiple comparison test (p<0.0001). HD ratio ranged mostly between 80% and 90%, and more than 95% of sapling stems were of high quality, with a straight, unbroken top, non-sweep, and non-diseased stem. On average, the annual height increment of saplings was 21.9 cm at 1 year, 43.3 cm at 5 years, 54.3 cm at 10 years, and 64.3 cm at 15 years. The overall height growth with age increased smoothly. According to the analysis of covariance, the annual height growth by crown class differed significantly. The regression analysis parameters revealed that annual height growth increased with age and dominant crown class.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.327-348
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• 2004

In this study, after analyzing several local climate characteristics of South Korea, I validated distribution, invasion, foraging, underground activities, attack season as ecological characteristics and also temperature, relative humidity, and tree species as preference characteristics of Korean termites (Reticulitermes speratus kyushuensis Morimoto). Especially, southern part of the Korean peninsula is a suitable area for inhabitation and motion of termites holding same ecological characteristic like R. speratus kyushuensis. Busan is a neighboring district at field distribution north limiting temperature of Coptotermes formosanus Shiraki and Chuncheon is a passing area through the Korean Peninsula of field distribution north limiting temperature of Reticulitermes speratus Kolbe. The termite attack of wood devices was about 34.5% for 3 years in the forest of Jongmyo. Although the attack rate of termite increased each year, the detection rate decreased and the missing rate was high by degrees. I confirmed a foraging habits which is a part of termite colony was a role of continuous decomposition and another was a role of new food hunt as experimental results. The foraging termites were found under ground at Jongmyo in Seoul from April to November in the 2001 and the most active period was on July and August. The termite invasion rate of bait station increased in every monitoring. Through the increasing attack rate of bait station during 2nd monitoring (November, 2000) and 3rd monitoring(March, 2001), I confirmed that termites moved into the deep underground in winter, and were working continuously to forage. R. speratus kyushuensis inhabiting at the Korean Peninsula is a species which has food consumption rate with higher temperature. The termite revealed the greatest amount of food(filter paper) at $30^{\circ}C$(90% RH), but showed increasing death rate at over $32^{\circ}C$. Also, survival rate of this termite was 97% at 84% RH($30^{\circ}C$), but killed 100% at 52% RH($30^{\circ}C$) and 70% RH($30^{\circ}C$). For wood feeding, this was observed the preference in a pine tree(Pinus densiflora) above all others. Survival of termites was high(87%) at a pine tree, but low(13.5%) at a paulownia tree(Paulownia coreana). In this study, I presented the biological characteristic of termite(R. speratus kyushuensis Morimoto) and confirmed the deterioration degree of termite on wooden cultural heritage in Korea. Depending on climate and soil temperature, each area in the southern part of the Korea Peninsula, has some different active period and different distribution of R. speratus kyushensis. With these results, I expect that this report helps to prepare the integrated pest management(IPM) of the termite on wooden cultural heritage in Korea, and it may help to reduce the economical loss from termite damage in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.46-52
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• 2009

Deposition of atmospheric N that is depleted in $^{15}N$ has shown to decrease N isotope ratio ($^{15}N/^{14}N$,expressed as ${\delta}^{15}N$) of forest samples such as tree rings, foliage, and total soil-N. However, its effect on ${\delta}^{15}N$ of mineral soil-N which is biologically active N pool has never been tested. In this study, ${\delta}^{15}N$ of mineral N($NH{_4}^+$ and $NO_3{^-}$) in forest soils from organic and two depths of mineral soil layers (0 to 20 cm and 20 to 40cm depth) of Pinus densiflora stands located at two distinct areas (rural and industrial areas) in southern Korea was analyzed to investigate if there is any difference in ${\delta}^{15}N$ of mineral N between these areas. We also evaluated potential N loss of the study sites using ${\delta}^{15}N$ of mineral N. Across the soil layers, the ${\delta}^{15}N$ of $NH{_4}^+$ ranged from +8.9 to +24.8‰ in the rural area and from +4.4 to +13.8‰ in the industrial area. Soils from organic layer (+4.4‰) and mineral layer between 0 and 20 cm (+13.8‰) of industrial area showed significantly lower ${\delta}^{15}N$ of $NH{_4}^+$ than those of rural area (+8.9 and +24.3‰, respectively), probably indicating the greater contribution of $^{15}N$-depleted $NH{_4}^+$ from atmospheric deposition to forest in the industrial area than in the rural area. Meanwhile, ${\delta}^{15}N$ of $NO_3{^-}$ was not different between the rural and industrial areas, probably because ${\delta}^{15}N$ of $NO_3{^-}$ is more likely to be altered by the N loss that causes $^{15}N$ enrichment of the remaining soil N pool. Compared with the ${\delta}^{15}N$ of soil mineral N reported by other studies (from -10.9 to +15.6‰ for $NH{_4}^+$ and -14.8 to +5.6‰ for $NO_3{^-}$), the ${\delta}^{15}N$ observed in our study was substantially high, suggesting that the study sites are more subject to the N loss. It was concluded that $NH{_4}^+$ rather than $NO_3{^-}$ can conserve the ${\delta}^{15}N$ signature of atmospheric N deposition in forest ecosystems.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.1-20
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• 1972

The trend and achievements of forest genetics research in abroad were investigated through observation tours and reference work and following facts were found to be important aspects which should be adopted in the forest genetics research program in Korea. Because of world wide recognization on the urgency of taking a measure to reserve some areas of the representative forest type on the globe before the extingtion of such forest type as the results of continuous exploitations of the natural forests to meet the timber demand all over the world, it is urgently needed to take a measure to reserve certain areas of natural stand of Pinus koraiensis, Pinus parviflora, Pinus densiflora f. erectra, Abies koreana, Quercus sp., Populus sp., etc. as gene pool to be used for the future program of forest tree improvement. And the genetic studies of those natural forest of economic tree species are also to be performed. 1. Increase of the number of selected tree for breeding purpose. Because of the fact that the number of plus tree at present is too small to carry out selection program for tree improvement, particularly for the formation of source population for recurrent selection of parent trees of the 2nd generation seed orchard it is to be strongly emphasized to increase the number of plus tree by alleviating selection criteria in order to enlarge the population size of plus trees to make the selection program more efficient. 2. Progeny testing More stress should be placed on carrying out progeny testing of selected trees with open pollinated seeds. And particular efforts are to be made for conducting studies on adult/juvenile correlation of important traits with a view to enable to predict adult performances with some traits revealed in juvenile age thus to save time for progeny testing. 3. Genotype-environment interaction Studies on genotype and environment interaction should be conducted in order to elucidate whether the plus trees selected on the good site express their superiority on the poor site or not and how the environment affect the genotype. And the justification of present classification of seed distribution area should be examined. 4. Seed orchard of broad leaf tree species. Due to the difficulty of accurate comparison of growth rate of neighbouring trees of broad leaf tree species in natural stand, it is recommended that for the improvement of broad leaf trees a seedling seed orchard is to be made by roguing the progeny test plantation planted densely with control pollinated seedlings of selected trees. 5. Breeding for insect resistant varieties. In the light of the fact that the resistant characteristics against insect such as pine gall midge (Thiecodiplosis japonensis U. et I.) and pine bark beetle (Myelophilus pinipera L.) are highly correlated with the amount and quality of resin which are known as gene controlled characteristics, breeding for insect resistance should be carried out. 6. Breeding for timber properties. With the tree species for pulp wood in particular, emphasis should be placed upon breeding for high specific gravity of timber. 7. Introduction of Cryptomeria and Japanese Cypress In the light of the fact that the major clones of Cryptomeria are originated from Yoshino source and are being planted up to considerably north and high elevation in Japan, those species should be examined on their cold resistance in Korea by planting them in further northern part of the country.

• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.167-176
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• 2016

This study was carried out to compare soil physicochemical properties and nutrient concentrations of tree leaf between planted forests following forest fire and an undisturbed forest in the Bongdaesan mountain, where is located in the Ulsan metropolitan city. We established three deciduous tree planting (Liriodendron tulipifera L., Prunus yedoensis Matsum and Quercus acutissima Carruth.) plots, one unplanted plot following four-year forest fire and one undisturbed plot (Pinus densiflora S et. Z). Carbon (C) stocks in the organic horizon were significantly lower in the tree planted plots ($2394-3551kg{\cdot}C{\cdot}ha^{-1}$) or the unplanted plots ($3689kg{\cdot}C{\cdot}ha^{-1}$) than in the undisturbed plot ($9388kg{\cdot}C{\cdot}ha^{-1}$). However, phosphorus (P), potassium (K) and magnesium (Mg) stocks in the organic horizon were not significantly different among the treatments. Soil water phase and soil pH were significantly higher in the P. yedoensis plot (water phase: 13.7-18.4%; soil pH: 4.62- 4.80) than in the undisturbed plots (water phase: 7.0%; soil pH: 4.10). Soil organic C concentration was slightly higher in the tree planted plots (1.89-3.60%) than in the unplanted (1.41%) plots. Soil Ca and Mg stocks at 10 cm of soil depth were significantly higher in the P. yedoensis and L. tulipifera plots than in the unplanted or undisturbed plots. Nutrient concentrations (Ca and Mg) of leaf were significantly higher in the L. tulipifera than in the Q. acutissima and the undisturbed pine plots. The results indicate that P, Ca, and Mg stocks in the organic horizon was not affected by tree planting, but Ca and Mg stocks at 10 cm of the soil depth were enhanced by the tree species established following four-year forest fire.