• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.171-177
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• 2004

The endoxylanase (642 bp; 213 amino acids) and $\beta$-xylosidase (1,602 bp; 533 amino acids) genes from Bacillus sp. were amplified by PCR and separately inserted into the downstream of the yeast ADH1 promoters, resulting in the pAEDX-1 (7.63 kb) and pAEX (8.47 kb) plasmids, respectively. When the yeast transformants, S. cerevisiae SEY2102 harboring pAEDX-1 or pAEX, were grown on YPD medium, the total activities of the enzymes were approximately 9.8 unit/ml for endoxylanase and 2.9 unit/m1 for $\beta$-xylosidase. When the three kinds of xylan from oat spelts, birch wood, and corncob were hydrolyzed by treating with recombinant endoxylanase and $\beta$-xylosidase, it was found that xylose, xylobiose, and xylotriose were produced. To efficiently hydrolyze xylan, various reaction conditions such as amount of enzymes, substrate type, substrate concentration, temperature, and reaction time were examined. The optimized conditions for the hydrolysis of xylan were as follows: amount of endoxylanase, 10 units; amount of $\beta$-xylosidase, 10 units; temperature, $50^\circ{C}$; substrate type, oat spelts xylan; substrate concentration, 6%; reaction time, 1 h. Under the optimal condition, xylose was mainly produced from oat spelts xylan by cooperative action of endoxylanase and $\beta$-xylosidase.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.167-176
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• 2008

Airborne pollen is known as one of the major causal agents to respiratory allergic reactions. Daily number of pollen grains was monitored using Burkard volumetric spore traps at seven locations including Seoul and Jeju during 1997-2007. Pollen grains were observed throughout the year especially from February to November. They showed similar distribution patterns of species among locations except in Jeju, where Japanese cedar vegetation is uniquely found. Peak seasons for pollen grains from trees and weeds were March to May and August to October, respectively. Tree pollens were mainly composed of pine, oak, alder, and birch. Weed pollens were mainly from Japanese hop, Worm wood, and ragweed. Diameter of pollen grains, which has a typical range of $20{\sim}60{\mu}m$, has close relationship with allergenicity. Allergenicity of tree and weed pollens is higher than that of grass pollens in general. In the case of trees and shrubs, pine trees account for about 70% of all tree pollens. However, pine pollens are weak allergens. The remaining 30% of tree pollens, including alder trees, white birches, and oaks, are moderate to strong allergens despite the smaller numbers. Grass and weeds are also highly likely to cause allergies. Especially, the pollens of Wormwood and Japanese hop are highly likely to cause allergies. Daily fluctuations in the number of pollens have to do with a variety of meteorological factors, such as temperature and rainfall.

• Journal of the Korean Wood Science and Technology
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• v.17 no.1
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• pp.3-11
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• 1989

This study was carried out to investigate the physical and mechanical properties. durability of adhesive bond and paint film for the basic data which were required to determine the suitability as a raw material for furniture the laminated veneer lumber (LVL) with pitch pine (Pinus rigida Mill). The results obtained were as follows; 1) The proper pressing time for making the LVL was over 45 second per milimeter of LVL thickness. 2) The bending strength of the LVL was lower than that of the solid wood but the compressive strength of the LVL was similar to that of the solid wood. The strength increased with the decrease of veneer thickness. 3) The impact bending absorbed energy of the LVL was 0 to 0.3 kg.m/$cm^2$ in the direction of parallel to the grain. The energy of the LVL was lower than that of the solid wood (0.68 kg.m/$cm^2$). 4) In warm water soaking and cold-dry tests, delamination of adhered layers surface crack, swelling, and color change were not found when the hot pressing time was over 45 second per milimeter of LVL thickness. As a result of soak under vacuum test shrinkage in the direction of parallel to the grain was about -1.0 percent and. was about 3.0 percent in the direction of the perpendicular to the grain. 6) The film cacks on the LVL's surface after the wet and cold-dry test were not found at all. 7) In the use of the LVL for interior decoration it was considered that the surface of the LVL be overlaid crossly with fancy veneers of birch and paulownia, etc. This cross overlayirg methods have resulted in few cracks on the fancy veneer.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.239-249
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• 1982

The outlines of superior stands, including species mixed, age classes, canopies, and ecological conditions of the stands, were examined in the forests of west Germany, Sweden, and Netherland. The establishment schemes of tree seed orchards for the production of high genetic quality seed were also investigated in the present study. 1. The meteorological conditions, abundant in precipitation and high in relative humidity, prove it to be oceanic climate characteristics in the Scandinavia located in high latitude and north-western part of Europe. The photo periodical characteristics following to day-length and the frost times determine the patterns of tree growth and distribution as well as the tree adaptability due to bud-setting and bud-flushing in Sweden forest. 2. The European forests are generally characterized by dense multistoried forest type composed of upper stories of tall tree species such as Norway spruce, fir, Scots pine and beech, lower stories of shade tolerant poles and saplings of spruce, fir, beech, and floor vegetations covered with birch, oak and hornbeam etc. 3. The single tree selection method and group shelterwood method are commonly applied for silvicultural system but shelterwood method and clearcutting method practiced partially in limited area. Badischer Femelschlagbetrieb and Bayerischer Femelschlagbetrieb are popularized to the regeneration of Schwarzwald but selection method applied in part. 4. Tree cuttings are properly limited so as not to exceed annual increment volume for the sustained yield and the preservation of ecosystem in European forest management. Land preservation and recreation function are more interested with the promotion of wood production in the forest management. 5. Careful attentions are paid to the reforestation of the introduced exotic species, such as Douglas-fir, red oak, pines from America, Japanese larch, Italian poplar etc., with concern against the insect and pest damage, and the meteorological damage. 6. Some intensive studies on tree improvement, such as selection of plus tree, selection of plus stand for seed collection, provenance trial, progeny test of clone, hybrid seed orchard for clone complexing, are performed in the countries and the great part of the seed required for reforestation are supplied from the seed orchard established in Sweden and Netherland.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.1-24
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• 1981

Kangweon-Do is rich in sightseeing resources. There are three sightseeing areas;first, mountain area including Seolak and Ohdae National Parks, and chiak Provincial Park; second eastern coastal area; third lake area including the watersheds of North Han River. In this paper, several methods of forestation were studied for landscaping the North Han River watersheds centering around Chounchon. In Chunchon lake complex, there are four lakes; Uiam, Chunchon, Soyang and Paro from down to upper stream. The total surface area of the above four lakes is $14.4km^2$ the total pondage of them 4,155 million $m^3$, the total generation of electric power of them 410 thousand Kw, and the total forest area bordering on them $1,208km^2$. The bordering forest consists of planned management forest ($745km^2$) and non-planned management forest ($463km^2$). The latter is divided into green belt zone, natural conservation area, and protection forest. The forest in green belt amounts to $177km^2$ and centers around the 10km radios from Chunchon. The forest in natural conservation area amounts to $165km^2$, which is established within 2km sight range from the Soyang-lake sides. Protection forest surrounding the lakes is $121km^2$ There are many scenic places, recreation gardens, cultural goods and ruins in this lake complex, which are the same good tourist resources as lakes and forest. The forest encirelng the lakes has the poor average growing stock of $15m^3/ha$, because 70% of the forest consists of the young plantation of 1 to 2 age class. The ration of the needle-leaved forest, the broad-leaved forest and the mixed forest in 35:37:28. From the standpoint of ownership, the forest consists of national forest (36%), provincial forest (14%), Gun forest (5%) and private forest(45%). The greater part of the forest soil, originated from granite and gneiss, is much liable to weathering. Because the surface soil is mostly sterile, the fertilization for improving the soil quality is strongly urged. Considering the above-mentioned, the forestation methods for improving landscape of the North Han River Watersheds are suggested as follows: 1) The mature-stage forest should be induced by means of fertilizing and tendering, as the forest in this area is the young plantation with poor soil. 2) The bare land should be afforested by planting the rapid growing species, such as rigida pine, alder, and etc. 3) The bare land in the canyon with moderate moist and comparatively rich soil should be planted with Korean-pine, larch, ro fir. 4) Japaness-pine stand should be changed into Korean-pine, fir, spruce or hemlock stand from ravine to top gradually, because the Japanese-pine has poor capacity of water conservation and great liability to pine gall midge. 5) Present hard-wood forest, consisting of miscellaneous trees comparatively less valuable from the point of wood quality and scenerity, should be change into oak, maple, fraxinus-rhynchophylla, birch or juglan stand which is comparatively more valuable. 6) In the mountain foot within the sight-range, stands should be established with such species as cherry, weeping willow, white poplar, machilus, maiden-hair tree, juniper, chestnut or apricot. 7) The regeneration of some broad-leaved forests should be induced to the middle forest type, leading to the harmonious arrangement of the two storied forest and the coppice. 8) For the preservation of scenery, the reproduction of the soft-wood forest should be done under the selection method or the shelter-wood system. 9) Mixed forest should be regenerated under the middle forest system with upper needle-leaved forest and lower broad-leaved forest. In brief, the nature's mysteriousness should be conserved by combining the womanly elegance of the lakes and the manly grandeur of the forest.