Driving force for forest fragmentation explored by land use change in Song watershed, India

Mehebub Sahana,Raihan Ahmed,Purva Jain,Haroon Sajjad 대한공간정보학회 2016 Spatial Information Research Vol.24 No.6

This study attempts to assess forest fragmentation and degradation in response to land use/land cover changes in Song watershed, India during 1998–2014. Landsat TM and Landsat 8 OLI satellite data across two dates (1998 and 2014) were used to analyze land use/land cover change and its impact on forest cover. The extent of forest degradation was analyzed using fragmentation model. Four categories of disturbance viz. core, perforated, edge and patch were obtained using 200 meters edge width. The result shows overall decrease of 7% in area under forest over 16 years. Area under open forest, mixed land use/land cover I (agriculture, forest and built up) and mixed land use/land cover III (agriculture and built up) has significantly increased while area under dense forest has decreased during the study period. Fragmentation model revealed lots of disturbance in forest located in mixed land use/land cover areas. Perforated and patch classes of forest have experienced a significant increase in their respective areas while core area has decreased at the expense of other fragmentation classes. Degradation of forest occurred at large scale at Hrishikesh and Thano forest ranges of Dehradun district and Gadol range in Tehri Garhwal district lying in the watershed. Rishikesh city in Dehradun district located in southern part of watershed recorded increase in patches due to developmental activities. Remote sensing and fragmentation model showed their effectiveness in analyzing forest degradation and monitoring the health of the forest in the watershed.

토지피복변화에 따른 금강 상류 댐 유역 산림 경관의 구조적 변화 분석

김경태,이현정,김휘문,송원경 한국환경생태학회 2023 한국환경생태학회지 Vol.37 No.4

Forests within watersheds are essential in maintaining ecosystems and are the central infrastructure for constructing an ecological network system. However, due to indiscriminate development projects carried out over past decades, forest fragmentation and land use changes have accelerated, and their original functions have been lost. Since a forest's structural pattern directly impacts ecological processes and functions in understanding forest ecosystems, identifying and analyzing change patterns is essential. Therefore, this study analyzed structural changes in the forest landscape according to the time-series land cover changes using the FRAGSTATS model for the dam watershed of the Geum River upstream. Land cover changes in the dam watershed of the Geum River upstream through land cover change detection showed an increase of 33.12 square kilometers (0.62%) of forests and 67.26 square kilometers (1.26%) of urbanized dry areas and a decrease of 148.25 square kilometers (2.79%) in agricultural areas from the 1980s to the 2010s. The results of no-sampling forest landscape analysis within the watershed indicated landscape percentage (PLAND), area-weighted proximity index (CONTIG_AM), average central area (CORE_MN), and adjacency index (PLADJ) increased, and the number of patches (NP), landscape shape index (LSI), and cohesion index (COHESION) decreased. Identification of structural change patterns through a moving window analysis showed the forest landscape in Sangju City, Gyeongsangbuk Province, Boeun County in Chungcheongbuk Province, and Jinan Province in Jeollabuk Province was relatively well preserved, but fragmentation was ongoing at the border between Okcheon County in Chungcheongbuk Province, Yeongdong and Geumsan Counties in Chungcheongnam Province, and the forest landscape in areas adjacent to Muju and Jangsu Counties in Jeollabuk Province. The results indicate that it is necessary to establish afforestation projects for fragmented areas when preparing a future regional forest management strategy. This study derived areas where fragmentation of forest landscapes is expected and the results may be used as basic data for assessing the health of watershed forests and establishing management plans. 유역 내 산림은 생태계 유지에 있어 중요한 역할을 맡고 있으며 생태네트워크 체계를 구성하는 주요 기반 환경이다. 그러나 지난 수십여 년간 행해진 무분별한 개발사업으로 인해 산림 파편화 및 토지이용 변화가 가속화되었으며 본래의 기능을 상실하게 되었다. 산림 생태계를 파악하는 데 있어 산림의 구조적 패턴은 생태적 과정과 기능에 직접적인 영향을 미치기 때문에 변화패턴을 파악하고 분석하는 것은 중요한 인자라 할 수 있다. 이에 본 연구는 금강 상류 댐 유역을 대상으로 FRAGSTATS 모델을 통해 시계열적인 토지피복변화에 따른 산림 경관의 구조적 변화를 분석하였다. 토지피복 변화탐지를 통한 금강 상류 댐 유역 내 토지피복변화는 1980년대부터 2010년대까지 산림 33.12㎢(0.62%), 시가화건조지역 67.26㎢ (1.26%) 증가하였고 농업지역 148.25㎢(2.79%) 감소하였다. 유역 내 산림 경관분석결과 No sampling 분석에서는 경관백분율(PLAND), 면적가중근접지수(CONTIG_AM), 평균 중심지 면적(CORE_MN), 인접지수(PLADJ)가 증가하였고 패치수(NP), 경관형태지수(LSI), 응집지수(COHESION)가 감소하였다. Moving window 분석을 통해 구조적 변화패턴을 파악한 결과, 경상북도 상주시, 충청북도 보은군, 전라북도 진안군 내 산림 경관은 상대적으로 잘 보전되어 있었으나 충청북도 옥천군, 영동군 그리고 충청남도 금산군 사이의 경계부와 전라북도 무주군과 장수군 인접 지역의 산림 경관에서는 파편화가 진행되고 있었다. 결과를 토대로 추후 해당 지역의 산림 관리전략 수립 시 파편화 지역을 대상으로 조림사업을 수립할 필요가 있을 것으로 사료된다. 본 연구를 통해 산림 경관의 파편화가 예상되는 지역을 도출할 수 있었으며, 유역 산림의 건전성 평가 및 관리계획 수립을 위한 기초자료로써 활용될 가능성을 기대할 수 있다.

통합 산림자원 관리와 디지털 산림정보 구축 지원을 위한 유역 기반 표준산림관리단위의 설정과 활용

노영희,민수희,홍성희,송정은,손학기,김종민 한국지도학회 2023 한국지도학회지 Vol.23 No.2

For efficient forest management, forest zoning methods must be defined with a certain spatial unit. Currently, national forests are divided into compartment and sub-compartment, and public and private forests are divided into parcel units. This dual spatial division system is not efficient in terms of unified forest planning and management. It can also lead to difficulties in creating and managing spatial forest information in the long-term perspective. In this study, we introduced forest zoning system based on mountain ridge watersheds and conducted an overlapping analysis with the current forest zoning system such as compartment and sub-compartment, working plan area, and forest thematic maps for utilization. As a result, we examined the spatial suitability of each scale of forest watershed unit proposed as a standard forest management unit and proposed the utilization of mountain ridge watershed-based standard forest management units for forest management and forest digital spatial data construction.

경기도(京畿道) 양평지역(陽平地域) 산림(山林) 소류역(小流域)의 수수지(水收支)와 계류수(溪流水)의 수질특성(水質特性)

김정유,한상섭,Kim, Jung-You,Han, Sang-Sup 강원대학교 산림과학연구소 2001 Journal of Forest Science Vol.17 No.-

본 연구는 양평군 계정리의 산림내 소유역(35ha)에 유입되는 강우와 유출되는 계류수를 통해 산지 물순환 과정에서 수수지(水收支)와 계류수질의 특성을 구명하기 위해 실시되었다. 산림 소유역의 임외우와 계류수를 대상으로 수량, pH, $Cl^-$, $NO_3{^-}$, $SO_4^{2-}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$ 등의 10개 항목에 대한 수질분석을 1998년 1월부터 1999년 12월까지 24개월 간 수행한 결과 다음과 같이 요약 할 수 있다. 계정리 산림내 소유역의 수수지(水收支)는 1998년 유입량은 1.547mm, 유출량은 958.6mm, 유출율 46.4%이였으며, 1999년 유입량은 1.467mm, 유출량은 872.4mm, 유출율 52.2%이였다. 조사기간동안 강우의 pH 평균은 5.6이였으며, 계류수의 pH 평균은 6.7로 강우에 비해 계류수의 pH가 높았다. 9개 분석 항목중 강우로 유입된 성분 총량(kg/ha)의 크기는 $SO_4{^{2-}}>NO_3{^-}>Ca^{2+}>NH_4{^+}>Cl^->Na^+>K^+>Mg^{2+}$의 순위였으며, 계류수로 유출된 성분 총량(kg/ha)의 크기는 $NO_3{^-}>Ca^{2+}>SO_4{^{2-}}>Na^+>Cl^->K^+>Mg^{2+}>NH_4{^+}$의 순위였다. 계류수의 수질 분석항목 중 $NH_4{^+}$(net:5.29kg/ha)을 제외한 모든 이온이 강우로 유입된 양보다는 계류수로 유출된 양이 더 많았다. This study was carried out to investigate the characteristics of water quality variations by stand water balance in YangPyong-Gun Gejung-Lee small forest watershed. Water quantity. pH, $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$ were monitored in open rainfall for one unit storm and long-term stream water in small forest watershed from January. 1998 to December. 1999. The results were summarized as follows: The runoff rate was 46.4% in 1998 and 52.2% in 1999. The average pH values of rainfall were 4.8 to 6.2 and those of stream water were 6.4 to 7.1 in small forest watershed. Total amount of input anion and cation values (kg/ha) in rainfall were $SO_4{^{2-}}>NO_3{^-}>Ca^{2+}>NH_4{^+}>Cl^->Na^+>K^+>Mg^{2+}$ and in stream water were $NO_3{^-}>Ca^{2+}>SO_4{^{2-}}>Na^+>Cl^->K^+>Mg^{2+}>NH_4{^+}$ in the order, respectively. The dissolved $NH_4{^+}$ was stored 5.29kg/ha and output of the other contents were more flow than input in small forest watershed.

삼림 소유역에 개설된 임도가 부유토사량 변화에 미치는 영향

안영상 ( Young Sang Ahn ),조희두 ( Hi Doo Cho ),오광인 ( Kwang In Oh ),채정기 ( Jyung Ki Chai ),전근우 ( Kun Woo Chun ) 한국산림과학회 2003 한국산림과학회지 Vol.92 No.1

To investigate if the stream in the forest watershed receives suspended sediment from the forest road, observations were carried out at three survey Points that receive effect of the forest road in forest watersheds and at one survey point that does not receive effect of the forest road in forest watersheds. According to the examination of the change of suspended sediments , they increased in place where there was forest road construction during rainfall and the maximum suspended sediment of each surveying Point differed . The suspended sediment in four surveying points was less than standard of drinking water(25mg/ℓ) with daily rainfall of 0mm, Under the 60mm of daily rainfall, suspended sediment of four surveying points did show more than standard of drinking water, under the 406mm of daily rainfall, suspended sediment was 67~246 times more at the surveying Point a, b and c than at the surveying point d.

산청 웅석봉군립공원 내 활엽수림유역의 강수와 유출특성

김기대 ( Ki-dae Kim ),최형태 ( Hyung-tae Choi ),임홍근 ( Hong-geun Lim ),박재현 ( Jae-hyeon Park ) 한국임학회 2017 한국산림과학회지 Vol.106 No.1

본 연구에서는 경상남도 산청군 웅석봉군립공원 내 활엽수림유역을 대상으로 산악성 강수특성과 녹색댐 기능을 구명하기 위해 총 6년 동안(2011~2016년) 수문 모니터링을 실시하였다. 산지(시험유역)와 평지(산청 기상관측소)의 강수특성을 비교한 결과, 평지에 비해 산지에서 강수량이 많았으며, 산지에서 강수강도가 높은 것으로 볼 때 산악성 강수효과가 작용하는 것을 알 수 있었다. 또한 조사대상 기간(2011~2016년)은 평년(1981~2010)에 비해 강수량이 증가하였고, 계절적 강수분배 등이 변화한 것은 나타나 기후변화로 인해 산청지역의 강수환경도 변화한 것으로 나타났다. 한편, 유출률은 봄이 가장 높게 나타났고 겨울, 여름, 가을 순으로 나타났으며, 이는 산지적설과 융설의 영향으로 판단된다. 그리고 유출수량은 여름, 봄, 가을, 겨울 순으로 높았으며, 총 유출량은 10,143.8 ton·ha·yr^-1로 산정되었다. This study aimed to investigate orographic precipitation and green dam (water conservation function) characteristics in a deciduous forest watershed in the region of Mt. Ungseok, Sancheong, Gyeongnam, South Korea. The rainfall and runoff of the watershed were monitored for six years (2011~2016) at the weather station and at the weir of the watershed, respectively. During the study period, the rainfall in the watershed (mountainous area) was larger than that of the meteorological station (flat area) nearest to the watershed. Besides, compared to the normal year (1981~2010), the rainfall has increased and the seasonal distribution of rainfall of the mountainous area has changed. These changes might have been caused by climate change. The runoff ratio was highest in spring, followed by winter, summer and fall, whilst the runoff was highest in summer, followed by spring, fall and winter. This difference seems to be due to the melting of snow in dry spring and intensive rainfall in summer. The total runoff in the watershed was calculated as 10,143.8 ton·ha·yr^-1.

다중시기 항공 LiDAR를 활용한 도시림 개체목 수고생장분석

김성열,김휘문,송원경,최영은,최재용,문건수 한국환경복원기술학회 2019 한국환경복원기술학회지 Vol.22 No.5

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.

산림소유역 유출수의 비강우일 비점오염물질 농도 변화 및 유출 특성 분석

유현주 ( Yoo Hyeon-ju ),최형태 ( Choi Hyung-tae ),김재훈 ( Kim Jae-hoon ),임홍근 ( Lim Hong-geun ),양현제 ( Yang Hyun-je ) 한국환경복원기술학회(구 한국환경복원녹화기술학회) 2020 한국환경복원기술학회지 Vol.23 No.6

This study was carried out to analyze the monthly runoff concentration on non rainfall days in order to prepare basic data to compare the runoff concentration on rainfall days in 7 forest watersheds in the Republic of Korea. Forest stream water has been collected through 15 times of sampling in each watershed and analyzed based on the changes in concentration of Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Organic Carbon(TOC), Total Nitrogen(TN), and Total Phosphorus(TP). The average concentration was 0.8 mg/L for BOD, 1.4 mg/L for COD, 0.8 mg/L for TOC, 1.85 mg/L for TN and 0.002 mg/L for TP during non rainfall days. Coniferous forested watersheds showed higher value of TN and TP concentration. Concentrations of BOD and TP in early March (p<0.01) were affected by melt water flow input in spring season. Significant differences (p<0.01) in concentrations were observed in BOD and TOC, indicating seasonal rainfall and vegetation growth impacts on forest stream quality. Concentration of TN and TP showed significant positive correlation, and weak negative correlation was found in the concentration of BOD and TOC. It is expected that result of forest stream water on non rainfall days could be basic information in managing non-point source from forest watersheds.

VOSviewer 프로그램을 이용한 산림유역 관련 연구동향 분석

이지은 ( Ji-eun Lee ),유리화 ( Rhee-hwa Yoo ),조민재 ( Min-jae Cho ) 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.6

In this study, we collected and analyzed domestic and international studies related to watersheds in the forest sector. Keyword co-occurrence analysis was conducted using the VOSviewer program to identify the research areas of domestic and international studies and the network structure to compare research trends. As a result, the number of research articles in international watershed-related studies showed an overall increasing trend, and the research areas were diverse and located close to each other, indicating that many convergence studies were conducted. On the other hand, the number of papers in domestic watershed-related studies seems to have stagnated overall from the past to the present, and the research areas are mainly focused on forest disasters and hydrology, with limited interdisciplinary convergence studies. In addition, in both domestic and international studies, watersheds are currently mentioned as research sites rather than management or analysis units in the forest sector. It is important to actively promote interdisciplinary research in Korea to provide a scientific and balanced basis for watershed-level forest management planning.

산림이 우세한 유역의 SWAT 모델에서의 유출량 평가

강동균 ( Kang Dong Kyun ),신용철 ( Shin Yong Chul ),최중대 ( Choi Joong Dae ),심혁호 ( Shim Hyuck Ho ),임경재 ( Lim Kyoung Jae ),전지홍 ( Jun Ji Hong ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

The Soil and Water Assessment Tool (SWAT) 모델은 높은 정확성 때문에 수문과 수질 모델링을 위해 여러 나라에서 널리 사용되어져 왔다. 그러나 산림유역에 대한 적용성 검토는 충분히 이루어지지 못해왔다. SWAT을 산림이 우세한 강원도 내린천 유역에 적용하였다. 먼저 모델보정은 4년간 유출량 모의치에 대하여 SLSOIL 인자를 변화시키면서 실시하였다. 모델 보정기간에서의 R²는 0.897, 그리고 E1 는 0.864였다. 보정결과를 모델에 적용하여 다른 4년간의 유출량 모의치에서 모델검정을 실시하였으며 R²는 0.878, 그리고 EI 는 0.842였다. 이러한 통계치는 SWAT이 내린천 유역에서 충분히 활용될 수 있다는 것을 보여준다. SWAT은 수문 자료를 이용해 유역의 토양유실을 모의한다. 향후, 내린천 상류지역에서 토양유실 방지를 위한 최적의 토양관리정책을 마련하는데 SWAT이 유용하게 사용될 수 있을 것이다. The Soil and Water Assessment Tool (SWAT) has been widely used for hydrology and water quality modeling in many countries due to its higher accuracy. However, limited studies have been investigated for its applicability in mountainous watershed. Thus, the SWAT was applied to forest-dominant Naerincheon watershed in Gangwon province, Korea. First the model was calibrated by changing the SLSOIL parameter for 4 year calibration period. The R² is 0.897 and El is 0.864 for the calibration period. The calibrated parameter was used for validation period and the R² is 0.878 and El is 0.842. These statistics show that the SWAT can be efficiently used for hydrologic modeling at Naerincheon watershed. Also, it is expected that the SWAT can be used to estimate water-erosion driven sediment loading to the Narioncheon watershed and to identify the best erosion control practices in upper stream areas in the Naerincheon watershed.