• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.1-6
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• 1996

Extracts from bark have been studied with a view to producing water-proof wood adhesives. Lately many softwoods, such as radiata pine from New Zealand and larch from Siberia, Russia, have been imported and utilized, and their residual barks would be expecting as potential raw materials for something useful chemicals. The great effort toward utilization of bark extractives as a chemical feedstock has been made on a worldwide level. However few report has been done for the utilization of tree bark extractives in Korea. Hot-water extracts were prepared from barks of Japanese larch(Larix leptolepis). Siberian larch(Larix gmelinii) and Radiata pine(Pinus radiata). The effect of various factors, such as particle size, liquor ratio, extraction temperature, and reaction time, on the extractive yields was discussed. Particle sizes affected the hot-water extractives: the finer the particle size, the higher extractives and extract efficiency. Higher temperature and higher liquor ratio were more effective. Extractives from Japanese larch were relatively less than those from Siberian larch and Radiata pine barks. Formaldehyde precipitates was the highest in extractives of Radiata pine barks. It could be concluded that Siberian larch bark was the best raw material for tannin adhesives, because its extractive yield was higher than those of the other barks.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.7-13
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• 1998

In order to reconstruct the traditional technology of Korean golden varnish(Hwangchil) made from the exudates of D. morbifera, this study in the second step was carried out to analyze the chemical composition and oil properties of the exudates for coatings and bark extractives made from the trees of D. morbifera more than 20 years old grown in Wando and Jejudo islands in the southwestern part of Korean peninsula according to the physiological seasons. The results obtained are as follows: 1. The exudates appeared to be a phytoalexin because it exudated after several days in tapping only in summer season. 2. Both the exudates and bark-extracts with acetone contained 50~60% unsaponifiables and 30~50% saponifiables 3. A major component of essential oil in bark-extractives was ${\beta}$-cubebene and reached to 60~80%, while that of exudates included only 34% ${\beta}$-cubebene and some other compounds such as ${\beta}$-cadinene of 12%, aromadendrene of 9%, ${\beta}$-selinene of 9%, CAS030021-74-0 of 10%, etc. in GC-MS spectrometer. 4. A mjor component of fatty oil fraction in bark-extractives was linoleic acid and reached to more than 60%, while the exudates had mostly other components such as terpenes and phenolics instead of fatty acids accordint to GC-MS spectrometer. 5. Iodine value of samples after oil refining had 214mg/g in the exudates and more than than 150mg/g in bark-extractives, so the latter belonged to a drying oil.. 6. Therefore, the exudates from D. morbifera for traditional Korean golden varnish seems to have beeen used to a good varnish because it has some specific compounds different from its bark-extractives or general varnishes.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.706-710
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• 2010

Understanding of chemical composition and energy contents in tree is important to develope strategies of renewable energy policy to cope with climate change. Residual biomass as renewable energy source was evaluated and focused on the bark-containing branches. Chemical analysis studies were conducted for different part of yellow poplar (Liriodendron tulipifera), which were partitioned to inner bark, outer bark, small branches, medium branches, big branches and trunk. The variations in hydrophobic extractives, hydrophilic extractives, lignin, carbohydrate compositions, energy contents (higher heating value) and the ash content were determined. The inner and outer bark had higher ash content, hydrophobic and hydrophilic extractives content, and higher energy content than those of tree trunk. Polysaccharides content in inner and outer bark was quite lower than those of stem or branches. Based on the energy content of residual biomass, replacement of fossil fuel and greenhouse gas emission abatement were calculated.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.51-56
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• 1996

The Bark lignin(alkali- and acid lignin), bark extractives(hot water-and $Na_2SO_3$ extractives) of Quercus acutissima and Pinus densiflora, and flavonoids were used to detect heavy metal adsorption. The adsorption ratio of heavy metals by lignin was assigned for 40 to 50%, but was not dependent on lignin kinds. However, in case of the addition of light metals such as $Ca^{++}$ and $Mg^{++}$ to lignin the adsorption ratio was increased by 20 to 40%, and $Pb^{++}$ was almost completely adsorbed. On hot water extractives, the adsorption ratio was very low because the substrate was water-soluble, so the substrate should be water-insoluble to adsorb the heavy metals. However, the adsorption ratios of $Cd^{++}$ and $Pb^{++}$ on $Na_2SO_3$ extractives were significantly increased, while those of $Zn^{++}$ and $Cu^{++}$, were similar to lignin. When four kinds of heavy metals were treated to $Na_2SO_3$ extractives together, more than 97% of $Pb^{++}$ and $Cu^{++}$ was adsorbed_ and $Zn^{++}$ was more adsorbed by 40%, and $Cd^{++}$ was not changed, comparing with the case that on kind of heavy metal was treated. There were differences between adsorption ratio of the kinds of flavonoids and heavy metals, and the adsorption ratio of heavy metals was assigned to 20 to 45% per 0.1g flavonoid.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.90-97
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• 1988

The rate of utilization of the oak cork (bark of Quercus variabilis Blume) ranges only 40-50%. Therefore, this study was carried out to investigate the chemical properties of the oak cork for increasing the utility. 1) The contents of alkali extractives, organic solvent extractives and ash in the oak cork are similar to those of other barks, but hot and cold water extractives and lignin contents are lower than those of the wood. The carbohydrate (cellulose and hemicellulose) content of the oak cork is similar to that of other barks. The suberin contents in the first and the second bark of the oak cork are 34.8 and 32.2% respectively, in the dry weight. 2) Inorganic component contents of the first bark are similar to those of the second. The pH of the first and the second bark are 3.9 and 4.2%. The caloric values of the first and second bark are 6,263 Kcal/kg, and 5,828 Kcal/kg, respectively, and these caloric values are higher than those of other barks. The sclerencymatous cell content of the first bark which is related to the quality of the oak cork is lower than that of second bark, the contents of the sclerenchymatous cell and lignin show the positive correlation. 3) In the dimension of the cross sectioned cork cell, the first bark is bigger than that of the second. The shape of the cork cell is globular shape in the early bark and discoid shape in the late bark. The cross and the radial section are the same shape, but the tangential section shows difference from the other section.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.24-28
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• 1997

As a way to revive the traditional technology of Korean golden varnish(Hwangchill), the exudates of D. morbifera, this study was carried out at first to investigate the anatomical characteristics and the chemical composition of D. morbifera stems and their exudates. Trees of more than 20 years old were harvested at Wando and Jejudo islands in the southwestern part of Korean peninsula during different physiological seasons of winter, spring, and summer, The results obtained are as follows: 1. In the anatomical aspect of wood, Hwangchil woods is ring-porous wood, has alternate inter-vessel pittings and horizontal intercellular canal in xylem. 2. In the chemical aspect of wood and bark, the general compositions appeared hot to differ from those of other hardwoods, and ash and alcohol-benzene extractives showed little increase with the increase of atmospheric temperature of harvesting season. 3. In the solvent-sequential extraction of bark, wood and exudate, the exudates was extracted up to 80% by ether, but the bark and wood contained a very small amount of ether extractives, about 2% in the bark and 0.5% in the xylem.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.28-33
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• 1994

The chemical compositions of pine bark from mechanical pulp industry were determined, and effect of Ca base acid sulfite on bark cooking was investigated under various conditions. The pine bark was composed of 39.5 % alkali extractives, 50.3 % lignin, and a small amount of carbohydrate. The contents of alkali extractives and lignin were remarkably higher than those of pine wood. The bark was composed of high content of arabinose and xylose, while the wood was composed of high content of mannose. When pine bark was cooked with 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid, but it was very difficult to delignify the bark by 50 % and over under these conditions. In the presence of 60~65 % free acid and at 155~165 $^{\circ}C$, initial cooking rate, delignification, and delignification selectivity were considerably increased, but condensation reaction of lignin was considerable at the end of cooking. Therefore, it was shown that pine bark was very difficult to delignify by the Ca-base acid sulfite cooking.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.42-51
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• 2000

Antimicrobial activity and antioxidative activity of the organosoluble extractives from the leaves, bark and xylem of Quercus dentata were investigated. Antimicrobial activity was tested by paper disk method and bioautography methods, The most pronounced antimicrobial activities of leaves parts were ethyl acetate solubles fraction against the Klebsiella pneumoniae by the paper disk method. The strongest activities of bark parts were ethyl acetate solubles fraction against Bacillus subtilis, Klebsiella pneumoniae. Ethanol extractives from xylem parts showed high activities against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae and Vibrio parahaemolyticus. These antimicrobial activities of ethanol extractives from Quercus dentata were in order to xylem > bark > leaves. The strong inhibition zones of the ethanol extractives and its fractions of xylem showed Rf values in 0.41~0.63. In leaves extractives, the petroleum ether solubles showed lower antioxidative activity and ethyl acetate insolubles showed higher antioxidative activity of 70% compared with the $EC_{50}$ values of the control. Antioxidative activity of bark and xylem extractives showed higher approximately 2 times than the control except the petroleum ether solubles.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.42-52
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• 2001

The barks of Fraxinus rhynchophylla, Fraxinus sieboldiana and Fraxinus mandshurica, ash trees grown in domestic, were collected, extracted with acetone-H$_2$O(7:3, v/v) and freeze dried to give some dark brown powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 and a TSK 40F column using a series of aqueous methanol, ethanol and ethanol-hexane mixture as eluents Some spectrometric analyses such as NMR and FAB-MS including TLC were performed to identify the structures of the isolated compounds. The bark extractives contained a large amount of coumarin derivatives in addition to a small amount of ester compounds.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.56-60
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• 1998

The bark of Fraxinus rhynchophylla, one of ash trees grown in domestic, was collected, extracted with acetone-$H_2O$(7:3, v/v) and freeze dried to give 50g of ethylacetate soluble powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 and a TSK 40F column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The extractives contained a large amount of coumarin derivatives in addition to a small amount of ester compounds such as ligstroside and oleuropein which have not been isolated from this tree species yet. Some spectrometric analyses such as NMR and FAB-MS including TLC were performed to identify the structures of the isolated ester compounds.