• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.242-250
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• 2022

Here we aimed to date the year and season of the resin collection from Korean red pines at Worak mountain and investigate the natural healing ability of the wounds using the tree-ring analysis technique. We determined the dating of the resin collection based on the synchronization between the ring-width time series from the wound surface of the experimental trees and the local master chronology, which is the mean time series from the sound surface on the opposite side of the wounds. For the dating of resin collection, we selected thirteen Korean red pines with resin wounds. For the investigation on the annual healing ability of the wounds, we sampled three dead trees out of 13 trees as disks. Through the comparison of the individual ring-width time series from the wounds with the local master chronology, it was verified that the resin collection was undertaken between the spring of 1962 and the autumn of 1975. The mean healing length of the wounds was 15.8 cm over the preceding 42 years, making their annual mean healing 0.38 cm. Through our study we successfully verified the healing ability of the wounded Korean red pines for the resin collection as well as the undocumented resin collection history.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.305-312
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• 2010

The purpose of this study is to compare the relative growth of annual ring width of red pine(Pinus densiflora), black pine(Pinus thunbergii) and pitch pine(Pinus rigida) by means of multiple regression method according to Graybill hypothesis. The obtained results are as follows. 1. The changes of rainfall have affected to tree growth during the periods of 1975 through 1978. 2. Among these pine trees, red pine was mostly influenced by environmental factors. 3. The growth of annual ring width was sensitively responded to the changes of rainfall and air temperature. 4. Among the heavy metals analyzed, the concentrations(ppm) of Lead(Pb) and Copper(Cu) were negatively effected on the growth of annual ring width of pine trees. 5. The analytical technique of annual ring width may be useful for estimation of the pollution in forest areas near industrial complexes.

• Computers and Concrete
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• v.34 no.4
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• pp.477-487
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• 2024

The in-situ stresses of concrete are an essential index for assessing the safety performance of concrete structures. Conventional methods for pore pressure release often face challenges in selecting drilling ring parameters, uncontrollable stress release, and unstable detection accuracy. In this paper, the parameters affecting the results of the concrete ring hole stress release method are cross-combined, and finite elements are used to simulate the combined parameters and extract the stress release values to establish a training set. The GridSearchCV function is utilized to determine the optimal hyperparameters. The mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R²) are used as evaluation indexes to train the gradient boosting decision tree (GBDT) algorithm, and the other three common algorithms are compared. The RMSE of the GBDT algorithm for the test set is 4.499, and the R² of the GBDT algorithm for the test set is 0.962, which is 9.66% higher than the R² of the best-performing comparison algorithm. The model generated by the GBDT algorithm can accurately calculate the concrete in-situ stresses based on the drilling ring parameters and the corresponding stress release values and has a high accuracy and generalization ability.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.469-476
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• 2021

Tricholoma matsutake is commercially important wild edible mushroom. The only method for cultivation of T. matsutake has been to use matsutake-infected pine trees. In this study, twenty-one fruiting bodies were collected from the matsutake-infected pine trees in the Hongcheon experimental site in 2020. The fruiting bodies from the existing production area of matsutake-infected pine tree and from its transplantation site were found to be identical through monitoring and analysis of 13 microsatellite markers. Transplanted matsutake-infected pine trees succeeded in fairy-ring formation and matsutake fruiting in 2010 and 2017 to 2020. In conclusion, the matsutake mycelium of transplanted matsutake-infected pine tree originates from the existing matsutake-infected pine tree production.

• Journal of Climate Change Research
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• v.9 no.3
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• pp.293-302
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• 2018

This study was carried out to provide basic information on efficient preservation and management of an Abies koreana forest through analyzing the ecological characteristics by slope in Seseok, Mt. Jirisan. Soil moisture content at southern and northern slopes was 29.9% and 21.7%, respectively, and there was no significant difference among soil properties between southern and northern slopes. The importance value of A. koreana in the southern and northern slopes was high for tree and subtree layers, respectively. It is noteworthy that many seedling and saplings of A. koreana were present on the southern slope. The species diversity was 0.413 for the tree layer, 0.632 for the subtree layer, and 0.609 for the shrub layer on the southern slope and 0.396 for the tree layer, 0.783 for the subtree layer, and 1.215 for the shrub layer on the northern slope. Evenness and dominance ranged from 0.371 to 0.609 and 0.629 to 0.391 on the southern slope and from 0.380 to 0.968 and 0.620 to 0.032 on the northern slope, respectively. The mortality of A. koreana was 9.6% on the southern slope and 24.4% on the northern slope, a distinct difference between the slopes. The mortality type at two slopes was the highest proportion of standing dead. Annual mean tree ring growth of A. koreana on the southern slope (1.76 mm/yr) was higher than that on the northern slope (1.64 mm/yr).

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.51-60
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• 2007

In this study, we consider the minimum ADM problem which is the fundamental problem for the cost-effective design of SONET ADM embedded in WDM ring networks. To minimize the number of SONET ADMs, efficient algorithms for the routing and wavelength assignment are needed. We propose a mathematical model based on the graph theory for the problem and propose a branch-and-price approach to solve the suggested model effectively within reasonable time. By exploiting the mathematical structure of ring networks, we developed polynomial time algorithms for column generation subroutine at branch-and-bound tree. In a computer simulation study, the suggested approach can find the optimal solution for sufficient size networks and shows better performance than the greedy heuristic method.

• 한국문화재보존과학회:학술대회논문집
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• 2003.03a
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• pp.27-27
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• 2003

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.146-151
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• 2001

No Abstract (See Full-text)

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.139-144
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• 2003

The purpose of this study is to identify the species and to date the woods used in the Keunjung-jeon Hall, main building of the Kyungbok palace in Seoul. Samples (144) were divided into two parts, pillars (52) and other wood materials (92). Only two species were identified. They were Abies holophylla Max. and Pinus densiflora Sieb. et Zucc.Eleven among 20 Pyungju (outer pillars) were Abies holophylla, and 9 were Pinus densiflora. Seven among 12 Naejinkoju (inner pillars) were Abies holophylla, and 5 were Pinus densiflora. Three among 4 Gwikoju (inner corner pillars) were Abies holophylla, and one was Pinus densiflora. In the other wood materials, only 2 of 92 were Abies holophylla, and the others were Pinus densiflora. Tree-ring dating proved that this building was reconstructed during late 1860s. It also revealed that the old woods cut in the 17th century were reused.

• Journal of the Korean Wood Science and Technology
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• v.51 no.5
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• pp.345-357
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• 2023

The present study conducted a stem analysis to trace growth information of Japanese larch (Larix kaempferi) and predict the future changes in growth volume. For this purpose, six L. kaempferi trees over 47 years old were cut at 1-2 m intervals from a height of 0.2 m, and circular plates of 5 cm thickness were collected for stem analysis. The analysis indicated that approximately 1-8 years are required to grow up to chest height. The annual height and diameter growth increased rapidly until the trees are 15 years old and gradually decreased after 20 years. The volume of 30-year-old trees in Oegam-ri forests, which were well-managed after artificial reforestation, was 0.4837 m³, whereas that in unmanaged Singi-ri forests was 0.1956 m³. Although the volume of individual trees differed greatly depending on the forest management status, it was found that the volume increased by 1.67-1.76, 2.49, and 3.49 times at 40, 50, and 60 years age, respectively, compared to the legal harvesting age 30. Therefore, factors such as the carbon dioxide reduction effect, forest management benefits, and the condition of trees at the site should be considered before harvesting trees.