Deforestation in Madagascar: debates over the island’s forest cover and challenges of measuring forest change

2014 ◽  
pp. 91-128
Keyword(s):  
Forest Cover ◽  
Forest Change

scholarly journals Evaluating Forest Cover and Fragmentation in Costa Rica with a Corrected Global Tree Cover Map

2020 ◽  
Vol 12 (19) ◽  
pp. 3226
Author(s):  
Daniel Cunningham ◽  
Paul Cunningham ◽  
Matthew E. Fagan
Keyword(s):  
Costa Rica ◽  
Forest Cover ◽  
Agricultural Land ◽  
Forest Area ◽  
Tree Cover ◽  
Agricultural Crop ◽  
Forest Change ◽  
Alos Palsar ◽  
Tropical Regions ◽  
The Impact

Global tree cover products face challenges in accurately predicting tree cover across biophysical gradients, such as precipitation or agricultural cover. To generate a natural forest cover map for Costa Rica, biases in tree cover estimation in the most widely used tree cover product (the Global Forest Change product (GFC) were quantified and corrected, and the impact of map biases on estimates of forest cover and fragmentation was examined. First, a forest reference dataset was developed to examine how the difference between reference and GFC-predicted tree cover estimates varied along gradients of precipitation and elevation, and nonlinear statistical models were fit to predict the bias. Next, an agricultural land cover map was generated by classifying Landsat and ALOS PalSAR imagery (overall accuracy of 97%) to allow removing six common agricultural crops from estimates of tree cover. Finally, the GFC product was corrected through an integrated process using the nonlinear predictions of precipitation and elevation biases and the agricultural crop map as inputs. The accuracy of tree cover prediction increased by ≈29% over the original global forest change product (the R2 rose from 0.416 to 0.538). Using an optimized 89% tree cover threshold to create a forest/nonforest map, we found that fragmentation declined and core forest area and connectivity increased in the corrected forest cover map, especially in dry tropical forests, protected areas, and designated habitat corridors. By contrast, the core forest area decreased locally where agricultural fields were removed from estimates of natural tree cover. This research demonstrates a simple, transferable methodology to correct for observed biases in the Global Forest Change product. The use of uncorrected tree cover products may markedly over- or underestimate forest cover and fragmentation, especially in tropical regions with low precipitation, significant topography, and/or perennial agricultural production.

Suitability of Global Forest Change data to report forest cover estimates at national level in Gabon

2016 ◽  
Vol 173 ◽  
pp. 326-338 ◽  
Author(s):  
Christophe Sannier ◽  
Ronald E. McRoberts ◽  
Louis-Vincent Fichet
Keyword(s):  
Forest Cover ◽  
National Level ◽  
Forest Change

scholarly journals The importance of glacier and forest change in hydrological climate-impact studies

2013 ◽  
Vol 17 (2) ◽  
pp. 619-635 ◽  
Author(s):  
N. Köplin ◽  
B. Schädler ◽  
D. Viviroli ◽  
R. Weingartner
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Catchment Area ◽  
Forest Cover ◽  
Control Period ◽  
Climate Impact ◽  
Glacier Retreat ◽  
Climate Scenarios ◽  
Forest Change ◽  
Impact Studies

Abstract. Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. The climate scenarios were derived from ten regional climate models from the ENSEMBLES project. Their respective temperature and precipitation changes between the scenario period (2074–2095) and the control period (1984–2005) were used to run a hydrological model. The relative importance of each of the three types of scenarios (climate, glacier, forest) was assessed through an analysis of variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland were analysed, exhibiting different degrees of glaciation during the control period (0–51%) and different degrees of forest cover increase under scenarios of change (12–55% of the catchment area). The results show that even an extreme change in forest cover is negligible with respect to changes in runoff, but it is crucial as soon as changes in evaporation or soil moisture are concerned. For the latter two variables, the relative impact of forest change is proportional to the magnitude of its change. For changes that concern 35% of the catchment area or more, the effect of forest change on summer evapotranspiration is equally or even more important than the climate signal. For catchments with a glaciation of 10% or more in the control period, the glacier retreat significantly determines summer and annual runoff. The most important source of uncertainty in this study, though, is the climate scenario and it is highly recommended to apply an ensemble of climate scenarios in the impact studies. The results presented here are valid for the climatic region they were tested for, i.e., a humid, mid-latitude mountainous environment. They might be different for regions where the evaporation is a major component of the water balance, for example. Nevertheless, a hydrological climate-impact study that assesses the additional impacts of forest and glacier change is new so far and provides insight into the question whether or not it is necessary to account for land cover changes as part of climate change impacts on hydrological systems.

scholarly journals Bi-Temporal Analysis of Spatial Changes of Boreal Forest Cover and Species in Siberia for the Years 1985 and 2015

2020 ◽  
Vol 12 (24) ◽  
pp. 4116
Author(s):  
Lei Tian ◽  
Wenxue Fu
Keyword(s):  
Boreal Forest ◽  
Forest Cover ◽  
Coniferous Forest ◽  
Temporal Analysis ◽  
Quantitative Information ◽  
Forest Change ◽  
Landsat Images ◽  
Latitude Zone ◽  
Broad Leaved Forest ◽  
Leaved Forest

Boreal forest is a sensitive indicator of the influence of climate change. It can quantify the level and spatial divergence of forest change for forest resources and carbon cycle research. This study selected a typical boreal forest affected by few human activities as a research area, in Siberia, with a latitude span of 51°N–69°N. A total of 150 Landsat images of this area acquired in 1985 and 2015 were collected. A hierarchical classification approach was first established to retrieve the information of forest cover and species. The forested and nonforested lands were discriminated by the decision tree method and, furthermore, the forested land was classified to broad-leaved and coniferous forests by a random forest algorithm. The overall accuracy was 90.37%, which indicates the validity of the approach. Finally, the quantitative information of the forest cover and species changes in each latitude zone of every 2° was analyzed. The results show that the overall boreal forest cover increased by 5.11% over the past three decades, with broad-leaved forest increasing by 3.54% and coniferous forest increasing by 1.57%. In addition, boreal forest increased in every latitude zone, and the spatial divergence of the changes of the boreal forest cover and species in different latitude zones were significant. Finally, broad-leaved forest increased more rapidly than coniferous forest, and the greatest increase, of up to 5.77%, occurred in the zone of 55°N–57°N.

scholarly journals Mapping Mangrove Forest Change in Nijhum Dwip Island

2019 ◽  
Vol 11 (1-2) ◽  
pp. 217-225
Author(s):  
MM Rahman ◽  
MAT Pramanik ◽  
MI Islam ◽  
S Razia
Keyword(s):  
Mangrove Forest ◽  
Forest Cover ◽  
Storm Surges ◽  
Forest Loss ◽  
Forest Conversion ◽  
Forest Cover Change ◽  
Forest Change ◽  
Change Analysis ◽  
Coastal Belt ◽  
Land Covers

Mangroves have been planting in the coastal belt of Bangladesh to protect the inhabitants of the coastal areas from cyclones and storm surges. Nijhum Dwip is located at the southern part of Hatiya Island. Most part of the island has been planted with the mangroves in the 1970s and 1980s; while parts of the mangroves have been deforested during the past few decades. The objectives of this research were to delineate and quantify the changes in the extent of mangroves in the island. The Landsat data of 1989, 2001, 2010 and 2018 have been utilized in the study. Three major land covers, namely forest, water and other land have been interpreted and delineated by using on-screen digitizing. The quantity of mangrove forest loss in the island is estimated as 1,024 ha, while 395 ha were afforested during 1989-2018. In the decadal change analysis, it was revealed that net forest cover change was higher in 2000s compared to other two decades and it was -425 ha. The result of the study is helpful to understand the extent and pattern of forest conversion in the island and to halt further forest loss and conserve the remaining forest. J. Environ. Sci. & Natural Resources, 11(1-2): 217-225 2018

20 years of forest change in Natura 2000 protected areas network

2020 ◽  
Author(s):  
Marinela-Adriana Chețan ◽  
Andrei Dornik
Keyword(s):  
Protected Areas ◽  
Satellite Data ◽  
Forest Cover ◽  
Natura 2000 ◽  
Temporal Analysis ◽  
Mean Value ◽  
Google Earth ◽  
Forest Change ◽  
Forest Protection ◽  
Forest Area Change

<p>Natura 2000 network, the world's largest network of protected areas, is considered a success for habitat and biodiversity protection, in the last decades. Our objective is to develop an algorithm for satellite data temporal analysis of protected areas, and to apply subsequently this algorithm for analysis of all Natura 2000 sites in Europe. We have developed an algorithm for satellite data temporal analysis of protected areas using JavaScript in Google Earth Engine, which is a web interface for the massive analysis of geospatial data, providing access to huge amount of data and facilitating development of complex workflows. This work focused on analysis of Global Forest Change dataset representing forest change, at 30 meters resolution, globally, between 2000 and 2018. Our results show that at least regarding forest protection, the network is not very successful, the 25350 sites losing 35246.8 km<sup>2</sup> of forest cover between 2000 and 2018, gaining only 9862.1 km<sup>2</sup>. All 28 countries recorded a negative forest net change, with a mean value of -906.6 km<sup>2</sup>, the largest forest area change recording Spain (-5106.4 km<sup>2</sup> in 1631 sites), Poland (-4529 km<sup>2</sup> in 962 sites), Portugal (-2781.9 km<sup>2</sup> in 120 sites), Romania (-1601.4 km<sup>2</sup> in 569 sites), Germany (-1365.7 km<sup>2</sup> in 5049 sites) and France (-1270.9 km<sup>2</sup> in 1520 sites). Among countries with the lowest values in net forest change is Ireland (-17.4 km<sup>2</sup> in 447 sites), Estonia (-104.1 km<sup>2</sup> in 518 sites), Netherlands (-132.3 km<sup>2</sup> in 152 sites), Finland (-268.6 km<sup>2</sup> in 1722 sites) and Sweden (-341.6 km<sup>2</sup> in 3786 sites).</p>

Global analysis of mountain forest distribution and change during 2000 to 2018

2020 ◽  
Author(s):  
Xinyue He ◽  
Dominick Spracklen ◽  
Joseph Holden ◽  
Zhenzhong Zeng
Keyword(s):  
Forest Cover ◽  
River Flow ◽  
Global Analysis ◽  
Tree Cover ◽  
Mountain Forest ◽  
Mountain Forests ◽  
Forest Change ◽  
Elevation Data ◽  
Forest Distribution ◽  
Hydrological Cycles

<p>Mountain forests cover a small fraction of the Earth’s surface, but may exert important influence on the hydrological cycles of river basins (e.g., evapotranspiration, river flow). Many montane ecosystems are currently experiencing forest loss or gain, due to direct land-use change and due to changes in climate. Previous studies revealed most deforestation and afforestation occur in the lowlands, while how forest cover changes at different altitudes in the mountains has not been fully understood. Here we present a study that aims to better understand the distribution of mountain forest change. We use a high-resolution global map of forest change during 2000-2018 combined with elevation data to complete a global analysis of the relationship of elevation with tree cover and tree cover loss and gain. We also assess which climate variables (temperature, rainfall, wind speed) might explain observed variations in tree cover. Our analysis provides new information on how and why mountain forests are changing.</p>

scholarly journals The importance of glacier and forest change in hydrological climate-impact studies

2012 ◽  
Vol 9 (5) ◽  
pp. 5983-6021 ◽  
Author(s):  
N. Köplin ◽  
B. Schädler ◽  
D. Viviroli ◽  
R. Weingartner
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Catchment Area ◽  
Forest Cover ◽  
Control Period ◽  
Climate Impact ◽  
Glacier Retreat ◽  
Climate Scenarios ◽  
Forest Change ◽  
Impact Studies

Abstract. Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. The climate scenarios consist of ten regional climate models from the ENSEMBLES project; their respective temperature and precipitation deltas are used to run a hydrological model. The relative importance of each of the three types of scenarios (climate, glacier, forest) is assessed through an analysis of variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland are analysed, exhibiting different degrees of glaciation during the control period (0–51%) and different degrees of forest cover increase under scenarios of change (12–55% of the catchment area). The results show that even an extreme change in forest cover is negligible with respect to changes in runoff, but it is crucial as soon as evaporation or soil moisture is concerned. For the latter two variables, the relative impact of forest change is proportional to the magnitude of its change. For changes that concern 35% of the catchment area or more, the effect of forest change on summer evapotranspiration is equally or even more important than the climate signal. For catchment with a glaciation of 10% or more in the control period, the glacier retreat significantly determines summer and annual runoff. The most important source of uncertainty in hydrological climate impact studies is the climate scenario, though, and it is highly recommended to apply an ensemble of climate scenarios in impact studies. The results presented here are valid for the climatic region they were tested for, i.e. a humid, mid-latitude mountainous environment. They might be different for regions where the evaporation is a major component of the water balance, for example. Nevertheless, a hydrological climate-impact study that assesses the additional impacts of forest and glacier change is new so far and provides insight into the question whether or not it is necessary to account for land cover changes as part of climate change impacts on hydrological systems.

scholarly journals STUDY OF THE STATE OF FORESTS OF THE ROSTOV REGION WITH THE USE OF MODERN GEOINFORMATION TECHNOLOGIES

2021 ◽  
Vol 2 (6) ◽  
pp. 100-109
Author(s):  
M.M. Streltsova ◽  
◽  
, O.E. Arkhipova ◽  
Keyword(s):  
Forest Fires ◽  
Forest Cover ◽  
Temporal Dynamics ◽  
Remote Sensing Data ◽  
Steppe Zone ◽  
The State ◽  
Forest Change ◽  
Space Images ◽  
Rostov Region ◽  
Geoinformation Technologies

The work is devoted to the study of the forests of the Rostov region, the determination of the spatio-temporal dynamics of the area of the territory covered with forest, using remote sensing data and geoinformation systems. The relevance of the study is due to the active anthropogenic impact on forests in the steppe zone, in a region with a forest deficit cover. The purpose of the study is to study the state of forests based on the use of modern geoinformation technologies, to assess the dynamics of forest cover in the forest fund of the Rostov region. The object of research is one of the most wooded areas of the Rostov region – the Verkhnedonsky. To study the state of the forests of the Rostov region, satellite images obtained using the Sentinel-2 spacecraft and data from the Global Forest Change application were used. Earth Engine. The efficiency of application of various methods of classification of space images has been investigated. It was revealed that despite the forest fires that affect the forests of the region due to climatic and natural factors, the area of gum massifs since 2015, in accordance with the classification carried out, has increased by about 300 hectares.

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