• 수산해양기술연구
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• 제58권1호
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• pp.39-48
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• 2022

Using environmental DNA (eDNA) in the fisheries and oceanography fields, research on the diversity of biological species, the presence or absence of specific species and quantitative evaluation of species has considerably been performed. Up to date, no study on eDNA has been tried in the area of fisheries acoustics in Korea. In this study, the biomass of a dominant species in the northwestern waters of Jeju Island was examined using 1) the catch ratio of the species from trawl survey results and 2) the ranking ratio of the species from the eDNA results. The dominant species was Zoarces gillii, and its trawl catch ratio was 68.2% and its eDNA ratio was 81.3%. The Zoarces gillii biomass from the two methods was 7199.4 tons (trawl) and 8584.6 tons (eDNA), respectively. The mean and standard deviation of the acoustic backscattering strength values (120 kHz) from the entire survey area were 135.5 and 157.7 m²/nm², respectively. The strongest echo signal occurred at latitude 34° and longitude 126°15' (northwest of Jeju Island). High echo signals were observed in a specific oceanographic feature (salinity range of 32-33 psu and the water temperature range of 19-20℃). This study was a pilot study on evaluating quantitatively aquatic resources by applying the eDNA technique into acoustic-trawl survey method. Points to be considered for high-quality quantitative estimation using the eDNA to fisheries acosutics were discussed.

• 한국산림과학회지
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• 제83권2호
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• pp.246-253
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• 1994

참나무류 주요 수종의 물질생산(物質生産)및 현존량추정식(現存量推定式)을 파악하기 위하여 전라남도 모후산지역(母后山地域) 순천대학교 연습림에 위치하고 있는 임관층(林冠層) 평균수령 26-29년생 상수리나무림, 굴참나무림, 졸참나무림과 36년생 신갈나무림 등 4개 수종 임분을 대상으로 임분별 10주씩 총 40주의 표본목(標本木)을 선정 벌목하여 조사하였다. 흉고직경 또는 흉고직경과 수고를 독립변수로 하는 3개 유형의 현존량(現存量) 대수회귀식(對數回歸式)을 임분별, 부위별 유도 검정한 결과 적합도(適合度)와 실용성(實用性)을 고려할 때 흉고직경을 독립변수로 하는 대수회귀식(logWt=A+BlogD)이 효과적인 것으로 나타났다. 흉고직경을 독립변수로 하는 4개 수종별 현존량 대수회귀식의 기울기와 절편간에는 유의적인 차이가 없음으로써, 참나무류의 현존량(現存量) 일괄추정식(一括推定式)의 가능성이 시사되었다. 임분(林分) 현존량(現存量)은 상수리나무림 164.0t/ha, 굴참나무림 158.9t/ha, 졸참나무림 115.3t/ha, 신갈나무림 118.8t/ha로써 상수리나무림과 굴참나무림이 졸참나무림과 신갈나무림에 비하여 40-50t/ha/yr. 정도 많았다 임분(林分) 순생산량(純生産量)은 상수리나무림 25.0t/ha/yr., 굴참나무림 23.2t/ha/yr., 졸참나무림 14.5t/ha/yr., 신갈나무림 12.6t/ha의 순으로 많았다. 임관층 평균수령과 순생산량을 고려할 때, 동일 임령의 경우 현존량(現存量)은 상수리나무림, 굴참나무림, 졸참나무림, 신갈나무림의 순으로 끊을 것으로 추정되었다. 신갈나무림의 경우 뿌리의 현존량(現存量)과 순생산량(純生産量) 구성비(構成比)가 다른 수종에 비하여 높은 값을 보였다. 순동화율(純同化率)은 졸참나무림 3.20, 신갈나무림 2.95, 상수리나무림 2.87, 굴참나무림 2.80의 순으로 높았다. 졸참나무림과 신갈나무림은 상수리나무림과 굴참나무림에 비하여 잎의 생산능률(生産能率)은 높은 반면 현존량(現存量)이 적기 때문에 임분(林分) 현존량(現存量)과 순생산량(純生産量)이 적은 것으로 나타났다.

• 대한원격탐사학회지
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• 제28권6호
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• pp.661-670
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• 2012

Urban forests provide great ecosystem services to population in metropolitan areas even though they occupy little green space in a huge gray landscape. Unfortunately, urbanization inherently results in threatening the green infrastructure, and the recent urbanization trends drew great attention of scientists and policy makers on how to preserve or restore green infrastructure in metropolitan area. For this reason, mapping the spatial distribution of the green infrastructure is important in urban environments since the resulting map helps us identify hot green spots and set up long term plan on how to preserve or restore green infrastructure in urban environments. As a preliminary step for mapping green infrastructure utilizing multi-source remote sensing data in urban environments, the objective of this study is to map vegetation volume by fusing LiDAR and multispectral data in urban environments. Multispectral imageries are used to identify the two dimensional distribution of green infrastructure, while LiDAR data are utilized to characterize the vertical structure of the identified green structure. Vegetation volume was calculated over the metropolitan Chicago city area, and the vegetation volume was summarized over 16 NLCD classes. The experimental results indicated that vegetation volume varies greatly even in the same land cover class, and traditional land cover map based above ground biomass estimation approach may introduce bias in the estimation results.

• 수산해양기술연구
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• 제60권1호
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• pp.27-36
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• 2024

The towing distance, which is speed over the ground, and the water flow quantity, which is speed through the water, were used when estimating the amount of Metapenaeus joyneri resources that rose to the surface at night using the swept area method in order to compare and analyze the difference. It was conducted using a shrimp dredge, trial fishing gear for catching Metapenaeus joyneri. Catch during the entire survey period was 188.9 kg. Monthly catch ranged from 3.1 to 109.2 kg, highest in June and lowest in September. The swept volume calculated using the speed over the ground was about 13% higher than using the speed through the water. Metapenaeus joyneri resources estimated using the towing distance ranged from 320.1 to 14,649.8 kg. Resources estimated using the water flow quantity ranged from 278.5 to 12,886.3 kg. Therefore, the amount of Metapenaeus joyneri resources estimated using the speed over the ground was about 14% higher than the method using the speed through the water, indicating that the amount of resources was overestimated.

• Journal of Forest and Environmental Science
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• 제30권4호
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• pp.351-361
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• 2014

Leaf area ($A_0$) and leaf biomass ($M_0$) estimation are significant prerequisites to studying tree physiological processes and modeling in the forest ecosystem. The objective of this study was to develop allometric models for estimating $A_0$ and $M_0$ of Swietenia mahagoni L. from different tree parameters such as DBH and tree height of mahogany plantations in the northeastern region of Bangladesh. A total of 850 healthy and well formed trees were selected randomly for sampling in the five study sites. Then, twenty two models were developed based on different statistical criteria that propose reliable and accurate models for estimating the $A_0$ and $M_0$ using non-destructive measurements. The results exposed that model iv and xv were selected on a single predictor of DBH and showed more statistically accuracy than other models. The selected models were also validated with an additional test data set on the basis of linear regression and t-test for mean difference between observed and predicted values. After that, a comparison between the best logarithmic and non-linear allometric model shows that the non-linear model produces systematic biases and underestimates $A_0$ and $M_0$ for larger trees. As a result, it showed that the bias-corrected logarithmic model iv and xv can be used to help quantify forest structure and functions, particularly valuable in future research for estimating $A_0$ and $M_0$ of S. mahagoni in this region.

• 자원ㆍ환경경제연구
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• 제28권3호
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• pp.415-435
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• 2019

본 연구의 목적은 중서부태평양(WCPFC) 수역 우리나라 원양연승어업의 눈다랑어 생산함수를 추정하여 규모 수익을 분석하는 것이다. 분석에 있어 투입요소는 선원수, 선박톤수, 투입낚시수, 눈다랑어 자원량 그리고 산출요소는 눈다랑어 생산량으로 하는 Cobb-Douglas 형태의 생산함수를 추정하였다. 함수 추정에 앞서 투입요소 중 눈다랑어 자원량은 Bayesian State-space 모델로 추정하였다. 생산함수 추정 결과, 하우즈만 검정을 통해 고정효과 모델이 선택되었고, 선원수를 제외한 선박톤수, 투입낚시수, 눈다랑어 자원량이 눈다랑어 생산량에 직접적인 영향을 미치는 것으로 나타났다. 추정된 생산함수의 투입요소를 바탕으로 규모 수익 수준을 분석한 결과, WCPFC 수역에서 눈다랑어를 조업하는 원양연승어업은 규모 수익 체증(IRS)의 성격인 것으로 추정되었다.

• 한국산림과학회지
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• 제99권1호
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• pp.62-67
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• 2010

경상남도 서부지역인 산청, 함양, 하동 3지역의 유사한 입지환경에서 생육한 약 40년생의 소나무임분을 대상으로 각 지역별 biomass 추정식을 개발하고, 소나무 biomass가 지역별로 차이가 있는지를 비교한 결과 흉고직경을 독립변수로 하고 소나무 각 부위별 건중량을 종속변수로 하는 상대생장식의 유의성이 인정되었으며(P<0.05), 결정계수($R^2$)의 값도 0.87-0.99 이상으로 회귀식의 적합도가 높게 나타났다. 소나무임분의 biomass는 지역간 유의적인 차이가(P<0.05) 나타났으며, 하동지역이 173.3Mg/ha로 가장 많은 양이 저장되어 있었고, 산청 131.0 Mg/ha, 함양 66.5 Mg/ha 순으로 나타났다. 현존량분포비율의 경우 3지역 모두 줄기>가지>줄기수피>잎 순으로 이중 줄기목질부 70.4-77.1%, 가지 10.9-15.2%, 줄기수피 8.9-10.4%, 잎 3.1-4.4% 정도 분포하였다. 본 연구결과에 따르면 경상남도 서부 지역 소나무임분의 지상부 현존량은 임목밀도와 지위 등이 원인이 되어 지역 간에 차이가 있었다.

• 한국산림과학회지
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• 제90권3호
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• pp.338-345
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• 2001

본 연구는 독일가문비나무의 지하부인 뿌리구조와 지상부인 수관과의 상호관계를 밝혀, 어렵게 뿌리를 굴취하거나 침엽 생체량을 측정하지 않고도 수고와 흉고직경에 의한 상대적인 뿌리와 침엽 생체량 추정을 위한 회귀식을 구하기 위하여 실시하였다. 독일 중부 Harz 지방의 Barbis 임분에서 30~40년생의 우세목 5본과 준우세목 3본을 선발한 후 조사목의 지상부에 대하여 수고, 흉고직경, 지하고, 침엽량, 가지량, 횡단면, 변재면 등을 조사하였다. 그리고 5본에 대해서는 지하부의 뿌리길이, 뿌리수, 뿌리무게, 뿌리횡단면 등을 수평과 수직뿌리로 구분하여 조사하였다. 조사된 염분에서 독일가문비나무의 지상부(수고, 흉고직경, 침엽량, 가지량 등)와 지하부(뿌리길이, 무게, 수, 횡단면 등) 생체량 사이에는 서로 밀접한 상관을 나타내었다. 측정이 용이한 흉고직경에 대한 지하부 뿌리생체량은 Y = 3.56X - 45.94의 관계식으로 결정계수가 0.96으로 매우 높은 상관관계를 나타내었다. 가지량, 침엽량과 수고에 있어서도 지하부 생체량과 높은 상관관계를 나타내었다. 본 연구에서 얻어진 회귀식은 30~40년생 독일 가문비나무 임분에서 흉고직경을 이용하여 지하부의 상대적인 뿌리 생체량을 추정하는데 유용하게 이용될 수 있을 것이다.

• Journal of Forest and Environmental Science
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• 제38권3호
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• pp.184-194
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• 2022

Triplochiton scleroxylon K. Schum is the plant species most affected by logging activities in the East Region of Cameroon due to its market value. This logging has impacted the ecological niche of the fern plant for which limited research has been done. The aim of this study is to contribute towards improving knowledge of fern richness and biomass on T. scleroxylon within the Central African sub-region. Fern data collection was done on 20 felled/harvested T. scleroxylon where, in addition to fern inventory, fern biomass was collected by the destructive method. The diameter and height of T. scleroxylon measured were used as explanatory variables in allometric equations for fern biomass estimation. Fern inventory was characterized using diversity index. Eight fern species were recorded on T. scleroxylon (≈5 species/T. scleroxylon). The minimum diameter where fern could be found is 59.4 cm. The average fern biomass found was 23.62 kg/T. scleroxylon. Pearson correlation coefficient showed a positive correlation (r>0.55) between fern biomass and T. scleroxylon diameter. For allometric equation, the logarithmic model improved better the adjustment than the non-logarithmic model. However, the quality of the adjustment is improved more when only the diameter is considered as an explanatory variable. Fern biomass is estimated to 90.08 kg/ha^-1 with 76.02 kg/ha^-1 being lost due to T. scleroxylon exploitation in the study area. This study is a contribution towards increasing knowledge of fern diversity specific to T. scleroxylon, and also fern biomass contribution to climate change mitigation and the potential carbon loss due to T. scleroxylon exploitation.

• 한국수산과학회지
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• 제42권5호
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• pp.487-493
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• 2009

Available ecological and fishery data of sailfin sandfish, Arctoscopus japonicus, was examined to ascertain its population dynamic parameters in Korean waters. The instantaneous coefficient of total mortality (Z) was estimated to be 1.361/yr, and annual survival rate (S) was 0.256. The estimated instantaneous coefficient of natural mortality (M) was 0.482/yr, and the instantaneous coefficient of fishing mortality (F) for recent years was calculated to be 0.879/yr from Z and M values. Age at first capture was estimated to be 1.958 years. These parameters, in conjunction with catch landings data between 1991 and 2008, were used to estimate annual biomass using a biomass-based cohort analysis. The biomass of A. japonicus was estimated at approximately 7,600 mt in 1991, but since 1994 decreased to below 4,000 mt by 2001. After 2002 they started to increase gradually, and showed the level of more than 5,000 mt in recent years.