• 한국산림과학회지
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• 제97권5호
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• pp.501-507
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• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.219-235
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• 2016

Forest tree diversity inventory and its periodical monitoring are important to understand changes in tree population structure and to provide information useful for biodiversity conservation and reserve management. In a long-term forest dynamics program in Indian tropical dry evergreen forest, this communication deals with tree diversity changes at decadal interval. The initial inventory of tree diversity was carried out in 2003, in four tropical dry evergreen forest sites - (much disturbed sites Shanmuganathapuram - SP and Araiyapatti - AP and moderately disturbed sites - Karisakkadu - KR and Maramadakki - MM) on the Coromandel Coast of peninsular India, by establishing four 1ha permanent plots, one in each site. In 2013, the four plots were re-inventoried for tree diversity (${\geq}10cm\;gbh$) changes which yielded 56 species from 46 genera and 26 families. The studied forest sites are threatened by disturbance due to multiple reasons; cutting of trees inside of the forest, grazing by goats, construction of temple approach road, and some aspects cultural attachment of local people like constructing new, additional strctures of temple by denuding a portion of forest etc.. Tree species richness over a decade increased by four species in site SP, two species in site AP, and one species in site KR, but decreased by one species in site MM. Tree density decreased drastically by 480 (28.92%) and 102 (12.63%) stems $ha^{-1}$ respectively in sites SP and AP, but moderately increased by 82 (12.09%) stems $ha^{-1}$ in site KR and 26 (3.46%) stems $ha^{-1}$ in site MM. Tree basal area declined in site KR from $21.6m^2$ to $20.26m^2ha^{-1}$ and in site SP from 21.1 to $20.38m^2ha^{-1}$, but increased from $19.1m^2$ to $19.43m^2$ and from 15.5 to $18.63m^2ha^{-1}$ in sites AP and MM respectively. Three tree species (Allophylus serratus, Maytenus emarginata and Ehretia pubescens) were lost out of the 57 species recorded in 2003, and two species (Jatropha gossypiifolia and Streblus asper) were new additions in ten years. The long-term forest monitoring data will be valuable to understand forest dynamics and for conservation and management of this and similar tropical forests.

• 한국산림과학회지
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• 제107권4호
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• pp.402-411
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• 2018

본 연구는 국가산림자원조사(NFI) 고정표본점 자료를 기반으로 우리나라에 분포하는 강원지방소나무와 중부지방소나무의 진계생장 추정식을 개발하기 위한 목적으로 수행되었다. 이를 위해 5년 동안의 진계생장량을 파악할 수 있는 정보를 제공하는 제5차 및 제6차 NFI의 동일 표본점 자료를 활용하였다. 진계생장 추정식 개발을 위한 2단계 접근법에 따라 첫 번째 단계에서는 진계생장 발생확률을 추정하기 위해 로지스틱 회귀모형을 이용하여 분석을 수행하였으며, 두 번째 단계에서는 진계생장이 발생한 표본점만을 대상으로 회귀식을 이용하여 진계생장량을 추정하였다. 또한 최적 모형의 선정은 회귀계수가 추정된 후보모형에 대해 모형의 평균편의(MD), 모형의 정도(SDD), 그리고 모형의 표준오차(SED)의 3가지 평가통계량을 분석한 결과에 근거하여 도출하였다. 그 결과 진계확률 추정식은 진계가 발생하지 않은 표본점 수에 기반한 로지스틱 회귀모형(모형 VI)이 선정되었고, 진계생장량 추정식에는 수종구성(SC) 변수를 포함한 지수함수식(모형 VII)이 최적모형으로 분석되었다. 이상과 같이 개발된 진계생장 추정식은 다양한 임분조건에 대해 추정능력을 평가하였으며, 적합도나 활용적인 측면에서 문제가 없는 것으로 평가되었다.

• Journal of Forest and Environmental Science
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• 제24권3호
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• pp.127-135
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• 2008

The mission of the Forest Inventory and Analyis (FIA) program of the Forest Service, U.S. Department of Agriculture, is to conduct the national forest inventory of the United States of America for purposes of estimating the area of forest land; the volume, growth, and removal of forest resources; and the health of the forest. Users of FIA data, estimates, and related products include land managers, policy and decision-makers, forest industry, environmental organizations, and university researchers. To accomplish its mission, the FIA program has established a sampling design with an intensity of approximately one permanent plot per 2,400 ha across the entire country. Depending on the region of the country, each plot is remeasured at intervals of five or 10 years. The program releases data annually and reports estimates at the county level for each state every five years. Due to budgetary constraints and natural variability among plot observations, sufficient numbers of plots cannot be measured to satisfy precision guidelines for the estimates of many variables unless the estimation process is enhanced using ancillary data. Classified satellite imagery has been demonstrated to be a source of ancillary data that can be used with stratified estimation techniques to increase the precision of estimates with little corresponding increase in costs. A crucial factor restricting the utility of FIA data is that the exact locations of inventory plots cannot be released to the public. Thus, users are generally not able to obtain estimates for small areas or for their own areas of interest if exact plot locations are required. To compensate, satellite imagery, inventory plot data, and the k-Nearest Neighbors technique are being used to construct Internet-based maps of forest attributes from which estimates for arbitrary user-defined areas of interest may be obtained.

• 인간식물환경학회지
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• 제24권6호
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• pp.629-638
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• 2021

Background and objective: This study was conducted to develop diameter growth models for thinned Quercus glauca Thunb. (QGT) stands to inform production goals for treatment and provide the information necessary for the systematic management of this stands. Methods: This study was conducted on QGT stands, of which initial thinning was completed in 2013 to develop a treatment system. To analyze the tree growth and trait response for each thinning treatment, forestry surveys were conducted in 2014 and 2021, and a one-way analysis of variance (ANOVA) was executed. In addition, non-linear least squares regression of the PROC NLIN procedure was used to develop an optimal diameter growth model. Results: Based on growth and trait analyses, the height and height-to-diameter (H/D) ratio were not different according to treatment plot (p > .05). For the diameter of basal height (DBH), the heavy thinning (HT) treatment plot was significantly larger than the control plot (p < .05). As a result of the development of diameter growth models by treatment plot, the mean squared error (MSE) of the Gompertz polymorphic equation (control: 2.2381, light thinning: 0.8478, and heavy thinning: 0.8679) was the lowest in all treatment plots, and the Shapiro-Wilk statistic was found to follow a normal distribution (p > .95), so it was selected as an equation fit for the diameter growth model. Conclusion: The findings of this study provide basic data for the systematic management of Quercus glauca Thunb. stands. It is necessary to construct permanent sample plots (PSP) that consider stand status, location conditions, and climatic environments.

• 한국산림과학회지
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• 제100권1호
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• pp.1-7
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• 2011

본 연구는 기존의 잣나무임분 거리독립 개체목 생장모델을 개선하기 위해 수행되었다. 직경생장함수 및 고사율함수의 매개변수들을 고정표본점의 정기평균생장량을 토대로 추정하고, 이 함수들의 특성을 기존의 총평균생장량을 토대로 추정한 모델과 비교하였다. 여기서 생장함수는 수관율함수, 잠재직경생장함수 및 임분을 구성하는 임목간 경쟁효과를 고려하기 위한 수정율함수를 의미한다. 고사율예측함수의 경우에는 고정표본점 자료의 한계로 인해 정기평균생장량 측정값을 구할 수 없어 대신 총평균생장량과의 관계식을 추정하여 대체하여 적용하였다. 연구결과 정기평균생장량을 토대로 하는 직경생장함수가 총평균생장량을 토대로 추정한 함수에 비해 개체목의 생장특성을 보다 현실적으로 반영하는 것을 보여주었다. 고사율함수의 경우, 총평균생장량을 적용하여 개발한 경우 고사율이 과대한 것으로 나타나는 문제가 있었으나 새로운 모델에서는 이 문제가 개선된 것으로 나타났다.

• Journal of Forest and Environmental Science
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• 제24권3호
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• pp.119-126
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• 2008

Growth and yield prediction methods, ranging from whole-stand models to individual-tree models, have been developed for forest types managed for wood production. The resultant models are used for a host of purposes including inventory updating, management planning, evaluation of silvicultural alternatives, and harvest scheduling. Because of the large investment in developing growth and yield models for improved genotypes and silvicultural practices for loblolly pine (Pinus taeda) in the Southern United States, this region serves to illustrate approaches for modelling intensively managed forests. Analytical methods and computing power generally do not restrict development of reliable growth and yield models. However, long-term empirical observations on stand development, which are time consuming and expensive to obtain, often limit modelling efforts. Given that growth and yield models are used to project present volumes and to evaluate alternative treatment effects, data of both the inventory type and the experimental type are needed. Data for developing stand simulators for loblolly pine plantations have been obtained from a combination of permanent plots in operational forest stands and silvicultural experiments; these data collection efforts are described and summarized. Modelling is essential for integrating and synthesizing diverse information, identifying knowledge gaps, and making informed decisions. The questions being posed today are more complex than in the past, thus further accentuating the need for comprehensive models for stand development.

• 한국응용곤충학회지
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• 제21권4호
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• pp.195-199
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• 1982

전국 9개 고정조사지에서 1968년이래 13개년간 조사한 솔나방의 10월의 밀도를 종합검토한바 다음과 같은 결과를 얻었다. 1. 13개년간에 솔나방의 10월밀도가 특히 높았던 년도는 '70년과 75년의 2회였으며 '76년이후는 단속 저밀도를 유지하고 있다. 2. 밀도가 현저하게 감소하였던 년도는 72년도와 76년도로서 8월중의 강우량 특히 24시간내 최대강우량이 밀접한 관계를 가지고 있었다. 3. 9개 조사지의 솔나방밀도증감은 대체적으로 유사한 경향을 보였으며 이것은 전국적인 강우의 대체적인 동시성에 기인한다고 본다. 4 8월중 일부 최다강우량이 100mm을 넘을 경우 솔나방밀도가 감소하는 확률은 $100\%$였다.

• Journal of Magnetics
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• 제22권1호
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• pp.60-64
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• 2017

Mischmetal of Bayan Obo ore was utilized to prepare the high performance $(Pr_{7.34}Nd_{21.86})_{1-x}MM_xFe_{68.7}Al_{0.1}Cu_{0.12}Co_{0.88}B$ ribbons using melt-spinning method. Phase composition and magnetic properties were investigated at room temperature. The ribbons mainly consist of $R_2Fe_{14}B$ phase in isotropic nanostructure. Both coercivity and maximum energy product decrease with the increase of MM content. The magnetic parameters of the ribbons with MM = 20 % in mass are $B_r=7.38kGs$, $H_{cj}=13.66kOe$, $(BH)_{max}=11.81MGOe$. Henkel plots were applied to demonstrate the exchange coupling interaction between grains.

• 한국산림과학회지
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• 제111권1호
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• pp.150-164
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• 2022

본 연구는 잣나무(Pinus koraiensis Siebold & Zucc.) 인공림을 대상으로 1차 및 2차 간벌에 따른 입목의 생장특성을 규명하여 산림시업지침 및 매뉴얼 개발을 위한 기초자료를 제공하고자 수행되었다. 사용된 연구자료는 간벌강도에 따라 설치된 잣나무 인공림 영구고정표준지로부터 수집되었으며, 각 간벌시험림별 4~5회 반복조사된 자료를 토대로 임령 19~43년생 시기의 흉고직경, 재적, 고사목 등 주요 입목 및 임분 현황을 분석하였다. 간벌강도에 따른 일원분산분석에서 개체목의 흉고직경 및 재적 변화는 유의적인 차이를 보였으며(p<0.05), 특히 간벌강도가 클수록 시간이 경과함에 따라 경급분포는 더 오른쪽에 위치하여 입목의 경급이 더 큰 것으로 관측되었다. 흉고직경 정기평균생장량의 경우, 간벌강도가 강하고 간벌 후 경과기간이 짧을수록 생장량이 높았는데, 구체적으로 임령 19~24년생 때 간벌강도별 생장량 범위는 0.48~0.95 cm/year이었다. 이후 2차 간벌에 따른 정기평균생장량도 강도간벌구에서 더 큰 것으로 분석되었으며, 임령 37~42년생 때 간벌강도별 생장량 범위는 0.29~0.67 cm/year이었다. 개체목 재적의 정기평균생장량은 간벌강도에 따라 차이가 있었으며, 흉고직경과 달리 시간이 지나도 크게 줄어들지 않는 경향이 나타났다. 임분 재적은 전반적으로 임분밀도가 밀한 표준지에서 높은 경향이었으나, 임분재적 정기평균생장량은 시기에 따라 무간벌뿐만 아니라 약도간벌이 이루어진 임분에서 더 높은 것으로도 분석되었다. 고사목은 무간벌구에서 가장 많이 발생하였으며, 반복조사가 진행될수록 임분밀도에 따른 고사목 본수 차이는 더욱 증가하였다. 종합적으로 임분밀도가 밀할수록 개체목의 흉고직경과 재적 생장량은 낮아지는 경향이었으나, 적절한 1차 및 2차 간벌이 시행되면 생장량은 다시 촉진되었다.