• Korean Journal of Environment and Ecology
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• v.14 no.4
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• pp.296-302
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• 2001

계룡산국립공원 연천봉고개(해발 700m)를 중심으로 남향사면인 시원사~원천봉고개와 북향사면인 갑사~연천봉고개를 대상으로 사면방향과 해발고에 따른 교목층과 아교목층의 산림구조를 조사분석하였다. 남향사면은 북향사면에 비하여 교목측의 밀도는 높은 반면 평균흉고직경은 작았다. 특수한 지형인 주능선부에 위치하는 정부를 제외하며, 해발고가 높아짐에 따라 교목층과 아교목층 전체의 평균흉고직경과 흉고단면적인 남향사면에서는 감소하는 경향을 보였다. 북향사면은 남향사면에 비하여 교목층과 아교목층 전체의 동다양도와 균재고가 높았다. 남향사면에서 해발고가 높아짐에 따라 중요치가 증가하는 수종은 느티나무, 졸참나무, 까지박달, 신갈나무등이었으며, 중요치가 감소하는 수종은 굴참나무, 서어나무, 때죽나무 등이었다. 북향사면의 경우 해발고가 높아짐에 따라 중요치가 증가하는 수종은 까치박달, 쪽동백나무 등이며, 중요치가 감소하는 수종은 때죽나무, 졸참나무 등이었다. Cluster 분석결과 남향사면중, 하부의 굴참나무-낙엽활엽수군집지, 남향사면 상부와 북향사면상, 중의 신갈나무-낙엽활엽수군집, 북향사면 하부와 정부의 신갈나무-소나무군집 등 3개 군집으로 구분되었다. 굴참나무, 산벚나무, 밤나무 등 3개 수종간에는 유의적인 정의 상관이 있었으며, 유의적인 정의 상관을 보인 굴참나무, 산벚나무, 밤나무 등 3개 수종은 당당풍과 유의적인 부의 상관이 있었다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.427-435
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• 2023

Changes in flowering time due to weather fluctuations impact plant growth and ecosystem dynamics. Accurate prediction of flowering timing is crucial for effective forest ecosystem management. This study uses a process-based model to predict flowering timing in 2023 for five major tree species in Korean forests. Models are developed based on nine years (2009-2017) of flowering data for Abeliophyllum distichum, Robinia pseudoacacia, Rhododendron schlippenbachii, Rhododendron yedoense f. poukhanense, and Sorbus commixta, distributed across 28 regions in the country, including mountains. Weather data from the Automatic Mountain Meteorology Observation System (AMOS) and the Korea Meteorological Administration (KMA) are utilized as inputs for the models. The Single Triangle Degree Days (STDD) and Growing Degree Days (GDD) models, known for their superior performance, are employed to predict flowering dates. Daily temperature readings at a 1 km spatial resolution are obtained by merging AMOS and KMA data. To improve prediction accuracy nationwide, random forest machine learning is used to generate region-specific correction coefficients. Applying these coefficients results in minimal prediction errors, particularly for Abeliophyllum distichum, Robinia pseudoacacia, and Rhododendron schlippenbachii, with root mean square errors (RMSEs) of 1.2, 0.6, and 1.2 days, respectively. Model performance is evaluated using ten random sampling tests per species, selecting the model with the highest R². The models with applied correction coefficients achieve R² values ranging from 0.07 to 0.7, except for Sorbus commixta, and exhibit a final explanatory power of 0.75-0.9. This study provides valuable insights into seasonal changes in plant phenology, aiding in identifying honey harvesting seasons affected by abnormal weather conditions, such as those of Robinia pseudoacacia. Detailed information on flowering timing for various plant species and regions enhances understanding of the climate-plant phenology relationship.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.279-285
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• 2012

This study was conducted to offer preliminary data for forest management from March and December 2011. Based on the number of standing trees by DBH classes, it is recommended to practice thinning and pruning to change the current young stand to mature stand. In Livelihood Environment Forest Protected Areas, young (0-10 years or 0-10 cm DBH) and detected trees need to be removed and selected healthy trees need to be heavily tended. Also, selected trees in age 20-30 (20-30 cm DBH class) need to receive concentrated tending. Since Livelihood Environment Forest Protected Areas had been vulnerable for erosion, the diversity of understory layer is low. In order to diversify deciduous trees, it is recommended to introduce new species and thin and prune existing trees. It is not proper to adapt clear cutting in a short time and should be partially regenerated using shelter-wood method or proper tending practices to the Pinus rigida dominanted forest. Tending existing under-story species including Quercus alina, Quercus variabilis, and Quercus serrata would be important.

• Korean Journal of Environment and Ecology
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• v.19 no.1
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• pp.19-30
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• 2005

The objective of this study was to monitor the edge vegetation development process after timber harvesting at deciduous hardwood forest in Seoul National University Forests of Baekwoonsan(Mt), Korea. From 1994 to 1999, Woody plants were monitored on two experimental plots established in 1994. The edge vegetation development pattern during the last six years(1994-1999) after timber harvesting is summarized as follows; Weigela subsessilis, Lindera erythrocarpa, Stephanandra incisa, Zanthoxylum schinifolium appeared to be a competitive species at the harvested forest edge. Staphylea bumalda, Lindera erythrocarpa, Viburnum erosum appeared to be a competitive species at harvested forest border between the harvested forest edge and the harvested interior. Weigela subsessilis, finders erythrocarpa, Lindera obtusiloba appeared to be a competitive species at the forest interior. The mean relative important value of major species were changed along the distance from the forest edge to the forest interior and seemed to be affected by aspect, and existing woody plants. But similarity indices seemed to be affected by distance. Species composition of forest edge(0-10m) was dissimilar to that of the other forest edge(40-50m). Species diversity indices, number of species and individuals were decreased according to the distance from the forest edge to the forest interior with passing time.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.540-547
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• 2011

This study was conducted to compare classification accuracy by tree species using QuickBird imagery for pixel- and segment-based classifications that have been mostly applied to classify land covers. A total of 398 points was used as training and reference data. Based on this points, the points were classified into fourteen land cover classes: four coniferous and seven deciduous tree species in forest classes, and three non-forested classes. In pixel-based classification, three images obtained by using raw spectral values, three tasseled indices, and three components from principal component analysis were produced. For the both classification processes, the maximum likelihood method was applied. In the pixel-based classification, it was resulted that the classification accuracy with raw spectral values was better than those by the other band combinations. As resulted that, the segment-based classification with a scale factor of 50% provided the most accurate classification (overall accuracy:76% and ${\hat{k}}$ value:0.74) compared to the other scale factors and pixel-based classification.

• Journal of Korean Society of Forest Science
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• v.5 no.1
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• pp.33-36
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• 1966

한국산(韓國産) 목재(木材)의 해부학적성질(解剖學的性質)에 관(關)한 연구(硏究)는 일정시수원고등농림학교(日政時水原高等農林學校)(현(現) 서울대학교(大學校)의 전신(前身)) 교수(敎授)인 일본인(日本人) 산림진씨(山林進氏)에 의(依)하여 이미 수백종(數百種)이 연구보고(硏究報告)된바 있다. 그러나 현재(現在)에는 도입(導入)된 외래수종(外來樹種)이 많고 또 이들 외래수종(外來樹種)으로 부터 생산(生産)되는 국산재(國産材)가 점차(漸次) 경제적(經濟的)으로 중요성(重要性)을 가증(加增)함에 따라 이들 목재(木材)에 관(關)한 기초적(基礎的)인 성질연구(性質硏究)가 시급(時急)하다고 생각(生覺)한다. 그러므로 이 시험(試驗)에서는 한국산외래수종(韓國産外來樹種)의 목재성질(木材性質)에 관(關)한 연구(硏究)의 일부분(一部分)으로 수십년전(數十年前)에 도입(導入)되어 비교적(比較的) 중요(重要)하다고 인정(認定)되는 일본원산(日本原産) 외래수종(外來樹種)의 목재(木材)에 관(關)한 현미경적성질(顯微鏡的性質)을 조사(調査)하여 보고(報告)하고져 한다. 이 시험(試驗)에서 사용(使用)된 공시재(供試材)는 경기도(京畿道) 수원(水原) 연습림(演習林)과 전라남도(全羅南道) 광양연습림(光陽演習林)에 생장(生長)하고 있는 35~48년생(年生)의 소나무, 곰솔, 일본잎갈나무, 일본젓나무, 편백, 삼나무, 및 일본목련 등 7개(個) 수종(樹種)에서 건전(健全)한 15개체(個體)가 선정시험(選定試驗)되었으며 결과(結果)는 중요(重要)한것들만 수종별(樹種別)로 종합(綜合)되었고 원문(原文)과 같이 간략(簡略)하게 기재(記載)되었다.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.387-396
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• 2005

Having employed the transitional probability model based on Markov chain, the study was carried out to examine successional trends for community types in the natural deciduous forest of Mt. Jumbong. The species composition of oncoming generation in overstory was estimated from that of mid-story, and the species composition in mid-story was based upon that of understory. Successional trend for each community was predicted from the reorganized probability matrix of tree replacement by the square of climax index, which was evaluated by the factors of light absorption, reproduction, and wood quality. As the result of analysis, following table shows the oncoming generation of steady state and dominant species in overstory and mid-story by community types. Even though Acer pseudo-sieboldianum and Carpinus cordata could hardly reach the canopy layer due to the intrinsic growth form, these species were predicted to maintain high compositional ratio so as to play an important ecological role in the study forest ecosystem.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.4
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• pp.247-254
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• 2003

This study was conducted to develop site index equations by main species grown in Gyunggi and Chungcheong provinces using environmental factors obtained from a digital forest site map. For this, 28 environmental factors were regressed on site index by species. Four to five environmental factors by species were selected as independent variables in the best site index equations (coefficients of determination greater than 0.91). For these site index equations, three evaluation statistics, mean difference, standard deviation of difference, and standard error of difference, were applied to the data set. Site index equations by species relationships developed in this study effectively estimate forest productivity in the study area. However, the site index equation of Larix leptolepis showed a larger than expected bias between the estimated and the measured site index. The reason is not clear in this situation, but might be because of the small sample set. It will be necessary, therefore, to conduct more studies to determine the exact reason. It is also expected that the site index equations with a few environmental factors as independent variables could provide valuable information about species well suited to given site conditions. Site index equations for other species should be developed to establish a rational policy about the selection of best species for site conditions.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.215-231
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• 2020

Forest landscape models (FLMs) can be used to investigate the complex interactions of various ecological processes and patterns, which makes them useful tools to evaluate how environmental and anthropogenic variables can influence forest ecosystems. However, due to the large spatio-temporal scales in FLMs studies, parameterization and validation can be extremely challenging when applying to new study areas. To address this issue, we focused on the parameterization and application of a spatially explicit forest landscape model, LANDIS-II, to Mt. Gyebang, South Korea, with the use of the National Forest Inventory (NFI) and long-term ecological research (LTER) site data. In this study, we present the followings for the biomass succession extension of LANDIS-II: 1) species-specific and spatial parameters estimation for the biomass succession extension of LANDIS-II, 2) calibration, and 3) application and validation for Mt. Gyebang. For the biomass succession extension, we selected 14 tree species, and parameterized ecoregion map, initial community map, species growth characteristics. We produced ecoregion map using elevation, aspect, and topographic wetness index based on digital elevation model. Initial community map was produced based on NFI and sub-alpine survey data. Tree species growth parameters, such as aboveground net primary production and maximum aboveground biomass, were estimated from PnET-II model based on species physiological factors and environmental variables. Literature data were used to estimate species physiological factors, such as FolN, SLWmax, HalfSat, growing temperature, and shade tolerance. For calibration and validation purposes, we compared species-specific aboveground biomass of model outputs and NFI and sub-alpine survey data and calculated coefficient of determination (R²) and root mean square error (RMSE). The final model performed very well, with 0. 98 R² and 8. 9 RMSE. This study can serve as a foundation for the use of FLMs to other applications such as comparing alternative forest management scenarios and natural disturbance effects.

• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.23-30
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• 2020

The use of increased computing power, machine learning, and deep learning techniques have dramatically increased in various sectors. In particular, image detection algorithms are broadly used in forestry and remote sensing areas to identify forest types and tree species. However, in South Korea, machine learning has rarely, if ever, been applied in forestry image detection, especially to classify tree species. This study integrates the application of machine learning and forest image detection; specifically, we compared the ability of two machine learning data collection methods, namely image data captured by forest experts (D1) and web-crawling (D2), to automate the classification of five trees species. In addition, two methods of characterization to train/test the system were investigated. The results indicated a significant difference in classification accuracy between D1 and D2: the classification accuracy of D1 was higher than that of D2. In order to increase the classification accuracy of D2, additional data filtering techniques were required to reduce the noise of uncensored image data.