Dryland Forest Research Articles

Prediction of erosion and sedimentation rates using SWAT (Soil and Water Assessment Tool) method in the Jenelata Sub Watershed

Erosion and sedimentation are problems that often occur in watershed ecosystems. The SWAT model (Soil and Water Assessment Tool) can be used to determine the output of a watershed’s performance. Jenelata sub-watershed area is one of the largest sub-watersheds of the Jeneberang watershed with 22.800 ha. This study aims to determine the spatial distribution of the hydrologic response unit (HRU) and analyze the rate of erosion and sedimentation in the Jenelata sub-watershed. The results showed that most HRUs are in secondary dryland forests with 447 HRU (19.09%). The level of erosion in the very light category, namely 5.74 ton/ha/year (37.53%) and light 34.71 ton/ha/year (27.76%), was in the villages of Moncongloe, Tana Karaeng, Sicini, Paladindang, Towata, Parang Lampoa, Manuju, and Buakkang. Meanwhile, moderate erosion was 104.07 ton/ha/year (23.92%), high 289.65 ton/ha/year (9.59%), and very high 553.74 ton/ha/year (1.20%) located in the villages of Pattallikang, Mangempang, Bontomanai, Bissoloro, Rannaloe, Jenebatu, and Sapaya. The largest sedimentation is 133.18 ton/ha/year in sub-watershed17, located in Bissoloro and Rannaloe villages.

Land use directions based on the level of land conversion vulnerability in the Padang Watersheds, North Sumatera

Hazardous land conversion in the Padang watersheds harms the hydrological conditions of the watersheds. Land use without considering the capacity and carrying capacity of the land results in decreased land productivity and increased watershed damage. This study aims to recommend directions for land use and land management in the Padang watersheds in areas that have a high and very high level of land conversion vulnerability. Analysis of land conversion vulnerability obtained by spatial modeling using ArcGis 10.3 software. The land cover data used in this study are data from the Ministry of Environment and Forestry in 2000 and 2019. Directions for land use are carried out through literature review in scientific journals, activity reports from both government and non-government agencies. Recommendations for land management directions are differentiated for urban areas and non-urban areas. Shrub cover that is vulnerable to conversion so that reforestation or other productive land uses are carried out with attention to soil and water conservation. Secondary dryland forest cover that is very vulnerable to conversion for partnerships with communities through community forestry/agroforestry schemes, rehabilitation and reforestation, and ecotourism. Plantation cover that is vulnerable to conversion can adopt an intercropping pattern of garden crops and seasonal crops. Agricultural land cover of dry land with high conversion vulnerability can adopt perennial crops at the land boundary and apply soil and water conservation. Residential areas in rural areas can adopt tree planting and make infiltration wells. The management direction for residential land in urban areas is to apply water conservation techniques (infiltration wells and polders) and arrangement of residential areas.

Land cover changes monitoring over ten years in upstream watershed of Deli Serdang Regency North Sumatra Province

Deli Serdang is one of the regencies in North Sumatra Province, experiencing relatively rapid development and population. Increasing in demand for the availability of land as living space. Two sub-districts of upstream watershed experienced changes in land cover, namely; Sinembah Tanjung Muda (STM) Hilir and STM Hulu. Monitoring changes in land cover in both sub-districts is essential, given that they are located in the upstream area of the watershed and will impact other areas in the lower watershed. This study aims to analyse land cover changes in both sub-districts over ten years (2009 - 2019). The method used in calculating land changes that occur is change detection. Field surveys were carried out to ensure that the land cover conditions on the land cover maps followed the field’s actual conditions. The research shows the period of 2009 – 2019, land cover that has increased in the area are mining, industry, open land, settlements, livestock and shrubs. The decrease in the area occurred in land cover, including dryland forest, mixed gardens and cultivated land.

Impact of land use change on hydrological conditions in the Karajae watershed, South Sulawesi Province

Land use is a representation of activities and utilization of land resources by the community. Land use has a big influence on the hydrological condition of a watershed. One of the small watersheds, in general, is the Karajae watershed, but it has a very large impact on the City of Pare-Pare, and the surrounding community. The Karajae watershed is the main water source for the people of Pare-Pare and agriculture. This study aims to analyze land use patterns that have a major impact on hydrological conditions in the Karajae watershed. The analysis begins with remote sensing methods to interpret land use using Landsat 7 image data in 2010 and Landsat 8 imagery in 2020. Next, analyze the pattern of land use change in detail in each forest area with a geographic information system approach. Analysis of hydrological conditions using the Soil and Water Assessment Tools approach with the input of the land use data. Land use Change 2010-2020 in the Karajae watershed shows additional land use in the form of settlements, rice fields, and dryland agriculture as a form of community activity. There are two forest areas in the Karajae watershed, namely production forest and protected forest. Production forest is dominated by dryland agriculture in the form of corn, beans, and horticulture, while the protected forest is dominated by and secondary dryland forest. This has an impact on hydrological conditions that there are fluctuations in discharge and an increase in sediment a decade ago. Optimal application of forest functions reduces discharge and sediment. Different forest planning for each forest function and land use within. Production forest with many activities directed towards community-based forest management such as community forest and village forest. As for the Protected Forest, which is dominated by grassland and shrubs, forest rehabilitation is carried out.

Potential and distribution of Vitex sp and Peronema canescens jack as anti –COVID 19 plants in East Kalimantan Province, Indonesia

Vitex sp and Peronema canescens Jack have long been known by local people in East Kalimantan Province as traditional medicines for fever, cold, diarrhea, hypertension and malaria. Now it is widely used as an alternative medicine for Covid 19 whose symptoms are fever and colds. Although the use of anti-Covid-19 drugs should be studied further, it is very important to know information on the potential and distribution of Vitex sp and Peronema canescens Jack in East Kalimantan. This research was conducted by collecting vegetation data from the seedling level to the tree level, using inventory method on research plots that were established scattered on secondary dryland forest cover in East Kalimantan with purposive sampling technique measuring 20 x 100 meters. The results showed there were 54 individuals of Vitex sp with 36 individuals at the tree level, 16 individuals at the pole level and 2 individuals at the sapling level. Based on density, the distribution of Vitex sp commonly found at the pole vegetation level. Peronema canescens Jack totaled 66 individuals with details of 29 individuals at the tree level, 25 individuals at the pole level, 7 individuals at the sapling level and there were 5 individuals at the seedling level. Based on density, the distribution of Peronema canescens Jack was found at the seedling and sapling levels. The stand volume of Vitex sp is 19.66 m3, with the average of potential volume of 3.61 m3 ha−1 and the highest potential is at the pole level. The stand volume of Peronema canescens Jack is 8.99 m3, with an average of potential volume of 3.22 m3 ha−1, and the highest potential is at the pole level at 5.26 m3 ha−1. The presence of Vitex sp and Peronema canescens Jack trees in secondary dryland forest in East Kalimantan can be a genetic resource for the cultivation of Vitex sp and Peronema canescens Jack trees as anti-COVID 19 plants in East Kalimantan.

Prediction of erosion and sedimentation rates using SWAT (soil and water assessment tool) method in Malino Sub Watershed Jeneberang Watershed

The increase in population will encourage the community to transfer the function of agricultural land in the Malino sub-watershed. Land use dramatically affects the level of erosion and sedimentation. The use of SWAT models can identify, assess, and evaluate the extent of a watershed’s problems. This study aims to determine the spatial distribution of HRU and analyze the rate of erosion and sedimentation in the Malino sub-watershed. The results showed that the most HRU is found in secondary dryland forests, as much as 624 HRU (32.21%). The level of erosion rate of the category is very light with an erosion value of 5.21 tons/ha/year, light 31.19 tons/ha/year, moderate 104.91 tons/ha/year, weight 267.10 tons/ha/year, and hefty 616.74 tons/ha/year. The most significant sedimentation rate was found in sub-watershed 18 of 71.97 tons/ha/year and subwatershed 10 of 13.31 tons/ha/year.

Gum Arabic Production and Population Status of Senegalia senegal (L.) Britton in Dryland Forests in South Omo Zone, Ethiopia

Senegalia senegal (L.) Britton is a multi-purpose dryland tree species that produces gum arabic, a commercially valuable product. However, this resource is underused in Ethiopian dryland areas. The aim of this study was to evaluate the population status and potential gum yield of S. senegal growing in natural stands in South Omo Zone, Ethiopia. Forty-five sample plots, each measuring 20 × 20 m, were established at 500 m intervals along transects, with 1 m2 subplots located within the main plots to determine regeneration. S. senegal trees with a diameter at breast height of between 2 and 12 cm were most prevalent. Forty-two tree species were associated with S. senegal, of which 16 were gum- and resin-producing species. S. senegal was positively associated with Vachellia tortilis, Senegalia mellifera, Vachellia nilotica, Commiphora edulis, and Dobera glabra. Senegalia senegal comprised approximately 35% of regenerating trees. The maximum gum arabic yield obtained was 3948 g tree−1. Linear models of dendrometric variables indicated that gum arabic yield is better predicted by tree diameter than by height. Despite the limitations of this pioneer survey, the population status and yield potential suggest that gum arabic could be sustainably produced and commercialized in natural stands of S. senegal in the studied dryland areas, providing local communities with supplementary seasonal incomes.

Ecosystem services provided by Prosopis cineraria (L.) Druce in the drylands of Southern and Western Asia

ABSTRACT Trees of the Mimosoideae are dominant species in hot subdesert areas worldwide, providing many services for ecosystems and humans. This group includes Prosopis cineraria (L.) Druce, a dominant species from the dryland forests of Southern and Western Asia. Human population density and activities in these arid areas have led to calls for an urgent consideration of ecosystem services and conservation biodiversity. We performed a literature review on P. cineraria, to determine how this species could contribute to ecosystem conservation, ecosystem restoration, and improving ecosystem services in its native distribution range. Prosopis cineraria is at the heart of a network of intricate interactions with biotic and abiotic factors in its environment. Water mobilization, nitrogen fixation, soil stabilization, and the shade and resources provided by P. cineraria are key elements in the consideration of this species for conservation programs. Moreover, P. cineraria is deeply entrenched in local culture and history. It is part of the local cultural identity and provides remedies, agro-ecological, recreational, and regulating services, such as protecting dunes against erosion. Prosopis cineraria is of huge ethnobotanical value in subdesert areas in its native range. Dryland forest conservation strategies could benefit greatly from targeting this species, and should be accompanied by research in the potential of P. cineraria for coping with climate change.

Pemetaan Daerah Rawan Longsor Menggunakan Machine Learning di Kecamatan Muara Tami, Kota Jayapura, Papua

One of the high landslide vulnerability areas in Indonesia is located in Muara Tami District, Jayapura City. The main factors triggering the landslide are steep slopes and high elevations. However, there are still several other factors that also influence the occurrence of landslides, such as vegetation, land cover, and curvature. Landslides that occur can cause damages to all parties, both material and non-material. Therefore, it is necessary to map landslide-prone areas as a non-structural mitigation planning. This planning is useful for identifying areas that are relatively safer from landslides so that the fatalities incurred can be minimized. In this mapping, several parameters are used that are thought to trigger landslides, then they are calculated by machine learning using the random forest method. Based on the parameters used, the eastern and northwestern areas have high slope and elevation values, high curvature contrast values, and dry land forest cover. These results indicate the high potential for landslide vulnerability in both parts of the study area. Meanwhile, areas with low potential for landslide vulnerability have a curvature of 0, a relatively low slope and elevation. The model accuracy value obtained by the random forest method is 0.9. This value is categorized as good enough because it shows that the parameters used are good enough in mapping landslide vulnerability in the study area. These results are also supported by the high sensitivity and specificity values ​​based on the ROC curve. Areas with high potential for landslide vulnerability are Mosso Village and the border between Skow Mabo, Skow Yambe, Koya Tengah, Koya Timur, and Holtekam. Meanwhile, areas with low landslide potential were Skow Sae Village, the central part of East Koya, the northern part of West Koya, and the southern part of Holtekam.

Radial Growth Response of Picea crassifolia to Climatic Conditions in a Dryland Forest Ecosystem in Northwest China

As an important barrier against desert invasion in Northwest China, Helan Mountains (HL), Luoshan Mountains (LS) and their natural forests have an extremely important ecological status. It is of great significance to study the relationship between forest growth and climate in this region under the background of global change. At present, relevant research mostly focuses on the Chinese pine (Pinus tabulaeformis Carr.), and little is known about how Qinghai spruce (Picea crassifolia Kom.) responds to climate change. To investigate the potential relationships between radial growth of P. crassifolia and climatic conditions in Ningxia, China, we collected tree-ring samples from P. crassifolia growing in the HL and LS and then established the standard tree-ring width chronologies for the two sites. Correlation analysis together with multivariate linear regression and relative contribution analyses were used, and results showed that radial growth in the HL was determined by the precipitation in the previous September, by the standardized evapotranspiration index (SPEI) in the current March and June, and by the maximum air temperature in the current September. The maximum air temperature in the current September contributed the most (0.348) to the radial growth in the HL. In the LS, radial growth was determined by the precipitation in the previous September and in the current March and by the minimum air temperature in the current July. The factor that made the most contribution was the precipitation in the current March (0.489). Our results suggested that in the wetting and warming future, growth of P. crassifolia in the HL will increase while that in the LS needs further investigation. Our results also provide a basis for predicting how P. crassifolia in northwest China will grow under the background of future climate change and provide a reference for formulating relevant management measures to achieve ecological protection and sustainable development policies.

The effect of Pare-Pare City’s development on land use/land cover change in Karajae Watershed

Pare-Pare City is one of the centers of industry, trade and sea transportation in Eastern Indonesia. It also continues to be developed marked by changes in land use/land cover (LULC) now and in the future. Pare-pare city’s development will greatly affect the Karajae watershed as a boundary of the hydrological ecosystem. The purpose of the study was to analyze the effect of the development of Pare-Pare City on the LULC of the Karajae watershed. Analysis of LULC change with the approach of Geographic Information Systems (GIS), remote sensing, Cellular Automata Markov Chain (CA-markov) for LULC projection, and Binary Logistic Regression for the impact of City development. Change in LULC in the actual period (2004-2018) indicates a significant increasing of settlement and dryland agriculture area, while secondary dryland forest, grassland and shrub have been reducing. However, the LULC projection in 2032 shows a huge change than the actual period. Settlement experienced an increasing in area twice than the actual period (2004-2018), this was followed by an increasing in deforestation as well. However, it is different from agriculture which has extensive decreasing, and shrub has increasing of area. So that it shows the pattern of shifting cultivation conducted by the farming community. The changes in LULC in the future are influenced by the settlement and the road network.

Analysis of the North Toraja Regency spatial plan by GIS analysis: Recreation ecosystem and ecotourism

Recreation and ecotourism as ecosystem services are pleasures that come from nature. Quantification and mapping as one of the key elements needed to improve the recognition and implementation of ecosystem services into decision making. Mapping of recreational and ecotourism ecosystem services as material for evaluating the RTRW of North Toraja Regency. The results of the evaluation of the RTRW become the basis for the development of tourist areas and plans for the development of infrastructure for the Toraja Regency in the future. This study aims to identify tourism object ecosystem services and analysis of services to the RTRW of North Toraja Regency. The value of ecosystem services is obtained from the weighting and scoring of geomorphology, natural vegetation, and land cover derived from expert opinion and analyzed by the AHP method. Land cover was identified using SPOT 6-7 Year 2019 imagery. 9 geomorphologies are dominated by volcanic mountains made of outer igneous rock with an area of 82,974.92 Ha. Natural vegetation is known that the vegetation of the lower monsoon forest (monsoon lower mountain forest) dominates with an area of 93,809.14 Ha. The mainland cover is secondary dryland forest with an area of 46,803 ha. The results showed that the index value of recreational and ecotourism ecosystem services was dominated by very high class with an area of 5,5014.82 ha. The harmony of tourism objects, ecosystem services and spatial patterns resulted in 10 tourist objects with a very low index. These 10 attractions are then directed as material for evaluating spatial patterns. Land with land cover that is difficult to change is adjusted to its closure. The closure of plantation land, agriculture and dry land agriculture is directed to become a horticultural area. Meanwhile, tourism objects prone to disasters are directed to be protected areas.

Thinning decreased soil respiration differently in two dryland Mediterranean forests with contrasted soil temperature and humidity regimes

The effects of a thinning treatment on soil respiration (Rs) were analysed in two dryland forest types with a Mediterranean climate in east Spain: a dry subhumid holm oak forest (Quercus ilex subsp. ballota) in La Hunde; a semiarid postfire regenerated Aleppo pine (Pinus halepensis) forest in Sierra Calderona. Two twin plots were established at each site: one was thinned and the other was the control. Rs, soil humidity and temperature were measured regularly in the field at nine points per plot distributed into three blocks along the slope for 3 years at HU and for 2 years at CA after forest treatment. Soil heterotrophic activity was measured in laboratory on soil samples obtained bimonthly from December 2012 to June 2013 at the HU site. Seasonal Rs distribution gave low values in winter, began to increase in spring before lowering as soil dried in summer. This scenario indicates that with a semiarid climate, soil respiration is controlled by both soil humidity and soil temperature. Throughout the study period, the mean Rs value in the HU C plot was 13% higher than at HU T, and was 26% higher at CA C than the corresponding CA T plot value, being the differences significantly higher in control plots during active growing periods. Soil microclimatic variables explain the biggest proportion of variability for Rs: soil temperature explained 24.1% of total variability for Rs in the dry subhumid forest; soil humidity accounted for 24.6% of total variability for Rs in the semiarid forest. As Mediterranean climates are characterised by wide interannual variability, Rs showed considerable variability over the years, which can mask the effect caused by thinning treatment.

Habitat Adaptation Mediates the Influence of Leaf Traits on Canopy Productivity: Evidence from a Tropical Freshwater Swamp Forest

Functional traits offer generalizability to the prediction of ecosystem processes such as production, and community-weighted mean trait values are increasingly used for such predictions. However, the underlying causal direction between traits and ecosystem processes are often indirect and sometimes even tenuous. In this study, we aimed to uncover underlying causal mechanisms between traits, habitat adaptation and canopy productivity. We used canopy production data estimated from leaf litter traps, and trait and habitat association data obtained from 40 permanent vegetation plots in the Nee Soon catchment in Singapore, which contains a heterogeneous mix of freshwater swamp and dry-land tropical forests. Mean canopy production across the catchment was estimated to be 768 g m−2 year−1, which is similar to other tropical dry-land forests in the region. Biweekly per-basal-area canopy production was found to be consistently lower in swamp than non-swamp plots, and positively correlated with monthly mean temperature. Structural equation models fitted to data of canopy production, leaf traits, plot type (swamp versus non-swamp), basal areas and habitat adaptations of 69 tree species–plot combinations suggested that tree species possessing leaf traits associated with more conservative resource acquisition strategies, viz. low specific leaf area, high leaf C:N ratio, and thicker leaves, are better adapted to stressful, waterlogged swamp conditions, but that this adaptation also reduces canopy—and likely total—net primary productivity. These observations suggest that the stressful conditions of waterlogged, anoxic swamp habitats significantly reduce the rate at which nutrients are cycled by communities found in such environments.

Environmental effects of development programs: Experimental evidence from West African dryland forests

Environmental effects of development programs are the subject of an ongoing debate. We contribute to this debate by studying effects of a randomly allocated, nationwide development program in The Gambia on deforestation, focusing on parts of the country with meaningful baseline forest cover. Our main finding is that the program caused significant increases in annual forest loss. Conservative benchmark estimates imply that 5.6% of all forest loss occurring within 1km of treatment villages during the eight post-program years resulted from the program. Accounting for spillovers, we estimate that the program explains about one quarter of the forest loss around all villages. Looking at possible channels, we find moderate treatment effects of the development program on household wealth and livestock holdings. Further, villages with limited access to markets drive the effect of the program on deforestation.

Rainfall-Runoff Simulation Using HEC-HMS Model in the Benanain Watershed, Timor Island

Floods in a watershed area are caused by reduced water recharge due to changes in land use, increasing their discharge volume. Benanain watershed is an extensive area with many tributaries. Watershed morphometrics provides initial information about the hydrological behavior and the hydrograph shape of flooding in these areas. Furthermore, rainfall-runoff modeling uses as a unit to approach the hydrological values of the flooding process. This study determines the physical characteristics of the Benanain watershed based on curve number (CN) values, land cover, peak discharge, and peak time. It was conducted on the Benanain watershed with 29 sub-watersheds covering 3,181.521 km2. Data were collected on the rainfall experienced for 13 years from 1996 to 2008 and analyzed using the Log Pearson Type III method, while the HEC HMS model was used for flood discharge analysis. HEC-HMS model must calibrate by adjusting the model parameter values until the model results match historical data such as initial abstraction, lag time, recession, baseflow values, and curve number. The results show that the curve number values range from 56.55 - 73.90, comprising secondary dryland forest and shrubs. Moreover, the rock lithology in the Benanain watershed is dominated by scaly clay and other rock blocks. This means the area has low to very low permeability, which affects the volume of runoff. The return period of a 1000-year flood discharge obtained a peak of 5,794.50 m3/s, with a peak time of ± 14 hours. Morphometry of the Temef watershed with large catchment, radial shape pattern, an average of steep slope river, and meandering affects the peak of flood discharge hydrograph and the peak time of the flood.

PERUBAHAN TUTUPAN LAHAN DI HUTAN KEMASYARAKATAN GAPOKTAN JAYA LESTARI PROVINSI LAMPUNG

The research, which was conducted at the Gapoktan HKm Jaya Lestari at the Bukit Punggur KPH, aimed to find out changes in land cover in the HKm work area in 2000, 2009 and 2017, and to determine the effect of the implementation of the HKm program on the condition of forest cover in these locations. This research data analysis used Geographic Information Systems (GIS). Image data analysis includes analysis of land changes carried out by identifying changes in objects in different images at the study site. The extent of each class was calculated from all image data series (2000, 2009 and 2017), then interpretation through descriptive data analysis. Based on the results of this study, the period 2000-2009 added the largest area of land cover in the Secondary Dry Land Forest (Hs) class (1.34% to 83.56%). The addition occurred due to a decreasing in the area of dryland agriculture cover (Pt) 55.48%, Open land (T) 12.91%, Primary dry land forest (Hp) 6.57%, Settlement (Pm) 4.95%, and shrubs (B) 2.34%. The 2009-2017 period of forest land cover which experienced the biggest change was the secondary dryland forest class (Hs), which experienced a decrease in area (83.56% to 46.08%) then primary dryland forest (HP) 7.06%, compared to inverted with settlement class (Pm) which increased 2.69%, followed by shrubs (B) 24.71%, open land (T) 20.56%, and dry land Agriculture (Pt) 3.54%. This provides an important finding and is based on the results of scientific analysis that the land cover in the form of forest trees in the area of Gapoktan management is reduced after the IUP-HKm is accepted by the community. It can be seen from the amount of additional cover in the form of shrubs, settlements and open land. Based on these conditions it is necessary to make efforts to improve the management system of HKm Gapoktan Lestari Jaya area through an agroforestry program.

ANALISIS KECUKUPAN RUANG TERBUKA HIJAU (RTH) KOTA BATAM

Batam City is an industrial city and has a total area of 1,570.35 km2 with a land area of 715 km2. Following the economic development and increasing population, the green open space in Batam City is decreasing. The purpose of this research was to analyze the adequacy of Batam’s green open space based on the criteria of Law No. 26 of 2007 concerning Spatial Planning and Minister of Public Works Regulation No. 5 of 2008 concerning Guidelines and Utilization of Green Open Space. This research was conducted with a spatial analysis method based on land cover information from the interpretation of Landsat 8 OLI image recording on 05-06-2018. Based on the results showed that Batam’s green open space is still 221.400 ha or 32.05% from land area. It means, Batam City’s open space is still sufficient at least 30% according to Law No. 26 of 2007 and Minister of Public Works Regulation No. 5 of 2008. The largest type of land cover in green open space is secondary dry land forest, covering 79.200 ha (11.45%). Keyword : Batam City, analysis, green open space.

Land Use-Land Cover Changed Analysis in Ogan Watershed, South SumatraDuring 2014-2019 Period

Land use-land cover (LULC) is one of the indicators commonly used in monitoring the quality of natural resources. Mostof the Ogan watershed is a peat ecosystem that plays an important role in maintaining the balance of the ecosystem andwater supply. During the 2014-2019 period the Ogan watershed experienced several wildfires and infrastructure development,particularly freeways. This study aims to analyze changes in the LULC in the Ogan watershed during the 2014-2019 period.LULC analysis uses remote sensing technology by utilizing Sentinel and Landsat satellite imagery data. LULC identificationused the visual image interpretation method, while LULC changes were analyzed using the GIS technique with the spatialoverlay method. The results showed that changes in LULC led to the LULC managed class, where the increase in areaoccurred in the rubber and oil palm plantation classes. Meanwhile, the highest reduction in area occurred in the dry landforest class. Changes in LULC that occurred during the observation period had a negative impact on the watershed in theform of land degradation, decreased levels of biodiversity and increased fire vulnerability. Based on these results, land use inthe Ogan watershed needs to be controlled and land management practices must pay attention to environmental sustainabilityaspects.

Assessment of land cover change over a period of five years in Deli Serdang, North Sumatra

Deli Serdang Regency is one of the districts in North Sumatra Province. Medan City is surrounded by Deli Serdang Regency. This study aimed to evaluate land cover changes that occurred during a period of five years (2014-2019) in Deli Serdang Regency by using a Geographical Information System (GIS). Changes in land cover are analyzed spatially using change detection available in the GIS application. Ground check is conducted to match the land cover type from the land cover map with actual conditions in the field. The land cover points taken in the field are taken using a Global Positioning System (GPS). The results showed that in a period of 5 years (2014-2019) there was a change in land use in Deli Serdang. The area of land use has increased, including: mangrove forest (5,176.57 ha to 5,645.23 ha), mining (211.93 ha to 387.47 ha), industry (2,944.64 ha to 3,316.39 ha), open land (726.12 ha to 1,063.57 ha), plantations (82,138.73 ha to 88,411.56 ha), settlements (20,537.91 ha to 21,347.85 ha), livestock (807.14 ha to 895.67 ha) and shrubs (3,761.61 ha to 3,013.33 ha). Areas of reduced land use include: dry land forest, mixed gardens, cultivation, rice fields, shrubs and ponds.