• Korean Journal of Plant Resources
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• v.36 no.1
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• pp.91-99
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• 2023

Plus tree selection is the essential first step in a tree improvement program. This study was carried out to select plus trees of black locust (Robinia pseudoacacia L.) for tree improvement in Korea. The candidate plus trees of black locust were selected from twenty-one places in the four provinces (Gangwon, Gyeonggi, Chungcheong and Gyeongsang) following comparison selection. The trees were examined for qualitative and quantitative traits of economic interest like tree height (H), diameter at breast height (DBH), clear bole height (CBH), stem straightness (SS), crown size (CS) and disease resistance. The 64 selected trees showed higher quality in growth characteristics than control trees. Average of height, DBH, CBH, SS and CS were 20.5 m, 31.1 cm, 10.1 m, 1.2 and 5.2 m respectively. In particular, it was shown that the growth characteristics were higher in Chungcheong population. The superiority percentage of selected candidate plus trees of black locust over their respective check trees ranged from 7.3% to 18.9% in height, 20.0% to 40.6% in DBH, 32.8% to 73.5% in CBH, 42.9% to 55.2% in SS and -11.1% to 9.4% in CS, respectively. The selected black locust will be useful in future tree breeding programs based on their clonal and progeny performance.

• Journal of Forest and Environmental Science
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• v.35 no.2
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• pp.115-120
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• 2019

There are many countries having a long history of exotic tree introduction from different countries and several countries including New Zealand, Brazil and Hungary have successfully introduced exotic trees. Korea's tree breeding program for introduction of exotic tree was originally started from 1924. Records reveal that hundreds of tree species were introduced from many countries and tested their germination and viability. About 415 introductions were eliminated since they had been introduced and tested. Subsequently, seven exotic trees that proved successful in trials and plantations have planted for afforestation. Simultaneously, several promising exotic trees are still under the test. In this paper, we will succinctly review and evaluate their comparative growth performance of the exotic trees in the plantation programs of the country to coping with climate change.

• Journal of Environmental Science International
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• v.32 no.1
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• pp.11-24
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• 2023

This study aimed to provide preliminary data for the improvement of the tree doctor qualification test (first written test), which was newly created by enforcing the Forest Protection Act on June 28, 2018., The high demand for system improvement accelerated this study. The results were analyzeds through literature and questionnaire surveys. Writing test questions and the license of the tree doctor qualification exam are currently managed by the Korea Forestry Research Institute, and it is deemed that the test should be entrusted to Human Resources Development Service of Korea for fair and transparent management. Additionally, the plan for the improvement of the subject-wise scope of examination questions writing, difficulty of test questions, and acceptance rate of the first test should be prepared after public hearings or seminars related to the examination questions.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.463-476
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• 2006

R-trees have been traditionally optimized for the I/O performance with the disk page as the tree node. Recently, researchers have proposed cache-conscious variations of R-trees optimized for the CPU cache performance in main memory environments, where the node size is several cache lines wide and more entries are packed in a node by compressing MBR keys. However, because there is a big difference between the node sizes of two types of R-trees, disk-optimized R-trees show poor cache performance while cache-optimized R-trees exhibit poor disk performance. In this paper, we propose a cache and disk optimized R-tree, called the PR-tree (Prefetching R-tree). For the cache performance, the node size of the PR-tree is wider than a cache line, and the prefetch instruction is used to reduce the number of cache misses. For the I/O performance, the nodes of the PR-tree are fitted into one disk page. We represent the detailed analysis of cache misses for range queries, and enumerate all the reasonable in-page leaf and nonleaf node sizes, and heights of in-page trees to figure out tree parameters for best cache and I/O performance. The PR-tree that we propose achieves better cache performance than the disk-optimized R-tree: a factor of 3.5-15.1 improvement for one-by-one insertions, 6.5-15.1 improvement for deletions, 1.3-1.9 improvement for range queries, and 2.7-9.7 improvement for k-nearest neighbor queries. All experimental results do not show notable declines of the I/O performance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.2
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• pp.27-38
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• 2003

This study aimed to provide basic data for future management of roadside trees by analyzing problems associated with plantation and management of roadside trees through categorization of functions and organizational structure, plantation and management, and management regulations and generating improvement opportunities based on the result of a survey on the awareness of government officials who are directly in charge of managing roadside trees in 31 cities & counties within Kyonggi province. The summary of key results of this study is as follows. First, "roadside tree-related function" is still not considered to be independent. About a half of government officials in charge did not majored in this field and they spent only about "2.09hours", in average, in the roadside tree-related function out of 8 working hours per day. Second, regarding problems and improvement opportunities in roadside tree-related function, lack of time was considered to be the biggest problem in overall management of roadside trees. As for improvement opportunities, "increase of dedicated manpower" and "system development" to facilitate efficient processing were suggested. Third, an annual budget for roadside tree-related affairs was merely 92 million won per city/county. A registry for management of roadside trees was kept manually. As for the roles of roadside trees, improvement of landscape and securing of green area itself were valued highly. Fourth, Ginkgo biloba, Zelkova serrata, and Prunus yedoensis were suggested to be the most appropriate species for roadside tree and Platanus occidentalis, Populus albaglandulosa, Populus euramericana, and Robinia pseudo-acacia were mentioned to be the least appropriate species.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.37-42
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• 1997

This study was carried out to track the heated-air flows within the tree disk through measuring the distribution of wood temperatures during explosing the 7.5mm-thick Japanese cedar disk and to investigate the effects of the time for the first explosion cycle and the number of explosion cycles on the improvement of permeability of tree disk. If the tree disk are explosed when the temperatures of the shell and core of it are not equilibrium yet, all of the inflated airs in the shell after explosion don't flow out toward the autoclave and some of them flow into the core of which the air pressures are lower than those of the shell. It is very effective for the improvement of permeability of tree disk to make the first explosion cycle when the temperatures of the shell and the core equilibrate at the setting temperature of steam in the autoclave. The more tree disks were explosed under the same conditions of first explosion, the more their permeabilities were improved.

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.82-86
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• 2018

Loblolly pine (Pinus taeda L.) is widely distributed in the southern part of the United States and it has been used as a major economic species in the region due to its excellent growth and stem straightness. The tree also grows only in the southern part of Korea because it is susceptible to cold. Recently climate changes have had widespread impacts on forest trees. Thus, the use of good quality seeds is prerequisite for assessing assisted migration adaptation trial. In this study, we conducted to investigate its cone and seed characteristics of each family, which is expected to improve seeds productivity for planting valuable timber trees. A total of 14 families were selected from the experimental forest in Boseong, Jeonnam province in 1981. The seed production capacity was estimated to range from 87.2 to 129.4 among families and the average was 111.3. The number of aborted ovules was investigated in the range of 11.4 to 29.5 for the first test and 7.4 to 22.2 for the second test. The average number of empty and filled seeds was 1.4 and 79.2 per cone, respectively. Based on the results, we can conclude that there is a strong correlation between the number of fertile scale and the seed production ability.

• Journal of the Korean Wood Science and Technology
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• v.47 no.5
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• pp.633-643
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• 2019

Growth characteristics [stem diameter (D), tree height (H)] and wood properties [Pilodyn penetration (P) and stress-wave velocity (SWV)] were measured for 65 families of 6-year-old Acacia mangium trees planted in Indonesia, in order to characterize their variation in D, H, P, and SWV. Therefore, the correlations between the measured characteristics were also determined, and their significant differences observed. Furthermore, their low to moderate values of narrow-sense heritability was obtained, and the results indicated the characteristics to be genetically controlled in A. mangium. In addition, highly significant positive correlations were observed among the growth characteristics, suggesting a close relationship, while there was no significant association between the growth characteristics and P, as well as SWV, indicating their independent. Therefore, these results demonstrate a potential for the improvement of both growth and wood properties of A. mangium trees, using the appropriate breeding programs. In addition, 18 families showed good performance in D and SWV, signifying their positive prospect of being considered as plus trees for the next generation breeding cycles.

• Landscaping Tree
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• v.56 no.5_6
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• pp.28-33
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• 2000

• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.40-50
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• 2004

This study was conducted to provide appropriate tending operation strategies for the natural deciduous forest, by the method of evaluating the stand quality, suggesting the removal plan for the undesirable trees, and predicting improvement cutting practice by tree quality evaluation. The results showed that average number of trees per ha was 717 stems, average DBH was 21.1cm. and average height was 13.6m. Canopy dominant species were in the order of Quercus serrata, Q. variabilis, Q. mongolica, Styrax obassia, and Ulmus davidiana var. japonica. Based on grades of four tree form factors for all tree in the study plots, we estimate the change of tree numbers. DBH and height with the improvement cutting by different tree grade. When the higher tree grade was applied to tending operation, the number of stem was decreased, but the values of DBH and height were not changed much, predicted to improve the stand quality.