• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.1-9
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• 2012

Densified fuels from biomass are widely used in North America and Europe as a regenerable and clean bioenergy. In this study, the fuel characteristics and densification characteristics of Japanese larch and Hyunsasi poplar were studied using a piston-type briquetting machine. The effects of pressure, pressure holding time, species, and particle size on briquette characteristics were studied. At room temperature, the highly densified briquettes of Japanese larch and Hyunsasi poplar can be produced at a compression pressure of 110~170 MPa. The produced briquettes have densities between 0.66 and 0.94 g/$cm^3$ after 28 days of storage at room temperature. The optimum pressure holding time was found to be 12 seconds. There is a linear increase in pressure with increase in density. The densities of briquettes from Japanese larch were higher than those of briquettes from Hyunsasi poplar. Also, the coarser particle size resulted in higher densities in briquettes than the finer particle size.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.54-59
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• 2003

Recently, densified pellet fuel from wood biomass is widely used at North America and Europe as a regenerable and clean carbon neutral bioenergy. High-pressure compaction of sawdust of Hyunsasi-poplar (Populus alba ${\times}$ P. glandulosa) to form a densified fuel was studied. Calorific and elemental analysis were carried out to assess Hyunsasi-poplar clones as fuels. Hot-press process was adopted for compaction of sawdust and compaction was performed under temperature from 100 to 180$^{\circ}C$, at pressure of 250 to 1000 kgf/$\textrm{cm}^2$, and for 2.5 to 10 minutes. Densified fuels were evaluated by its oven-dry density and fines after 5-minute shaking test. The target density and fines of densified fuels were over 1.2 g/$\textrm{cm}^2$ and below 0.5%, respectively. When the press-temperature is over 160$^{\circ}C$, densified fuels with density eve. 1.2 g/$\textrm{cm}^2$ and with fines below 0.5% can be produced. And the pressure over 750 kgf/$\textrm{cm}^2$ was effective for this production. It was found that the optimum press condition for preparation of densified fuel was 180$^{\circ}C$ -1000 kgf/$\textrm{cm}^2$ minutes.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.4
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• pp.171-175
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• 2011

This study was conducted to determine the susceptibility of 15 clones of native and foreign poplar species and their hybrids to Melampsora leaf rust and to select resistant clones at a nursery stool bed. Rust severities of individual trees were determined by estimating the percentage of infected leaves on the trees in addition to comparing the infected leaves with the infection diagrams. Three hybrids out of 15 clones were selected as resistant clones to the Melampsora leaf rust in Korea. Bong-wha 1 and Hyunsasi 3 belong to section Leuce, and Dorskamp belongs to section Aigeiros. Based on our results, we recommend Dorskamp as the best resistant clone to poplar leaf rust.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.15-21
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• 2006

The objective of this research is to develop the technique for carbonization of wood pellet and analyze a possibility for the utilization of carbonized wood pellet. The properties of wood pellet charcoals, such as density, yield, elemental composition, higher heating value, and methyleneblue adsorption, were analyzed. Wood pellet was made of sawdust of Hyunsasi-poplar, Japanese larch, Korean pine, Korean red pine, and Jolcharn-oak (serrate oak), respectively. The high density charcoal ($0.5{\sim}0.7g/cm^3$) was yielded from densified wood pellet. The carbon contents and calorific values of wood pellet charcoals were increased with the increase of carbonization temperature. The methyleneblue adsorptivity of wood pellet charcoal was similar to that of wood charcoal.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.291-296
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• 2012

Triploids are a useful tool for biomass production and molecular breeding of trees with a long life span. Triploids of the poplar 'Hyunsasi' (Populus alba ${\times}$ P. glandulosa) have been developed by crossing between female diploids and a male tetraploid. The tetraploid was developed around the 1970s at Korea Forest Research Institute by colchicine-induced chromosome doubling. Seedlings of the $F_1$ generation were analyzed using flow cytometry to verify their ploidy status. The mean relative fluorescence index of 3 F1 poplars, labeled as Line- 1, Line-17, Line-18, were approximately 1.5 times higher than those of diploid poplars, and the results clearly indicated that they were triploids. The phenotype of the F1 poplars included larger leaves and thicker stem than diploids, and abnormal leaf morphology, especially in the triploid 'Line-18'. Three triploid lines developed roots more slowly and had less roots than diploid. However, 3 poplar cytotypes (2x, Line-1, Line-17) rooted within 10 days on MS medium. In contrast, compared with the 3 cytotypes, the Line-18 showed about 80% and 70% in the rooting rate and the number of roots. The triploid poplars could be directly utilized for biomass production and with their sterility, they could serve as basic material for genetic transformation. In addition, flow cytometric analysis proved to be an effective and reliable method for screening forest trees for their ploidy level.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.198-203
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• 2013

Herein we analyzed the nuclear DNA content and the histological characteristics of the triploid of the 'Hyunsasi' (Populus alba ${\times}$ P. glandulosa $F_1$) which were developed for biomass production and molecular breeding research. The flow cytometric analysis showed that the nuclear DNA content of the 3 triploids were 1.6 times greater than those of the diploid. In terms of histological characteristics, the cross-section area of the stem of 'Line-18' was 1.6 times larger than that of the diploid. The area of pith, and cortex and phloem of the stem of 'Line-18' was also 1.6 and 2.0 times larger than that of the diploid, respectively. Moreover, the length and area of guard cell of 'Line-18' was 1.2 times larger than that of the diploid. These results helps to understand the cytological characteristics of the triploid poplar clones, and further investigations in the growth rate and wood properties of the triploids growing in the field will determine whether the triploid poplars are good candidates for molecular breeding programs and for the improvement of industrial biomass productivity.