Quantification of global forest change has been lacking despite the recognized importance of forest ecosystem services. In this study, Earth observation satellite data were used to map global forest loss (2.3 million square kilometers) and gain (0.8 million square kilometers) from 2000 to 2012 at a spatial resolution of 30 meters. The tropics were the only climate domain to exhibit a trend, with forest loss increasing by 2101 square kilometers per year. Brazil's well-documented reduction in deforestation was offset by increasing forest loss in Indonesia, Malaysia, Paraguay, Bolivia, Zambia, Angola, and elsewhere. Intensive forestry practiced within subtropical forests resulted in the highest rates of forest change globally. Boreal forest loss due largely to fire and forestry was second to that in the tropics in absolute and proportional terms. These results depict a globally consistent and locally relevant record of forest change.

High-Resolution Global Maps of 21st-Century Forest Cover Change

http://www.dpi.inpe.br/Miguel/Michelle/Referencias/Ecologia_da_Paisagem/BiologicalConservation_SpecialIssue_2009/02_Ribeiro_et_al_biocons_2009.pdf

The Brazilian Atlantic Forest:: how much is left and how is the remaining forest distributed? Implications for conservation

Timely and accurate change detection of Earth's surface features is extremely important for understanding relationships and interactions between human and natural phenomena in order to promote better decision making. Remote sensing data are primary sources extensively used for change detection in recent decades. Many change detection techniques have been developed. This paper summarizes and reviews these techniques. Previous literature has shown that image differencing, principal component analysis and post-classification comparison are the most common methods used for change detection. In recent years, spectral mixture analysis, artificial neural networks and integration of geographical information system and remote sensing data have become important techniques for change detection applications. Different change detection algorithms have their own merits and no single approach is optimal and applicable to all cases. In practice, different algorithms are often compared to find the best change detection results for a specific application. Research of change detection techniques is still an active topic and new techniques are needed to effectively use the increasingly diverse and complex remotely sensed data available or projected to be soon available from satellite and airborne sensors. This paper is a comprehensive exploration of all the major change detection approaches implemented as found in the literature.

/pdf/change-detection-techniques-4g34rgajio.pdf

Change detection techniques

▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

Mitigation and Adaptation Strategies for Global Change

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1056&context=civilengfacpub

Landsat-8: Science and Product Vision for Terrestrial Global Change Research

Tropical deforestation is a key contributor to species extinction and climate change, yet the extent of tropical forests and their rate of destruction and degradation through fragmentation remain poorly known. Madagascar's forests are among the most biologically rich and unique in the world but, in spite of longstanding concern about their destruction, past estimates of forest cover and deforestation have varied widely. Analysis of aerial photographs (c. 1953) and Landsat images (c. 1973, c. 1990 and c. 2000) indicates that forest cover decreased by almost 40% from the 1950s to c. 2000, with a reduction in ‘core forest’ > 1 km from a non-forest edge of almost 80%. This forest destruction and degradation threaten thousands of species with extinction. Country-wide coverage of high-resolution validated forest cover and deforestation data enables the precise monitoring of trends in habitat extent and fragmentation critical for assessment of species' conservation status.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0376892907004262

Fifty years of deforestation and forest fragmentation in Madagascar

NASA has sponsored the creation of an orthorectified and geodetically accurate global land data set of Landsat Multispectral Scanner, Thematic Mapper, and Enhanced Thematic Mapper data, from the 1970s, circa 1990, and circa 2000, respectively, to support a variety of scientific studies and educational purposes. This is the first time a geodetically accurate global compendium of orthorectified multi-epoch digital satellite data at the 30- to 80-m spatial scale spanning 30 years has been produced for use by the international scientific and educational communities. We describe data selection, orthorectification, accuracy, access, and other aspects of these data.

NASA’s Global Orthorectified Landsat Data Set

Biomass burning in the tropics, a large source of trace gases, has expanded drastically in the last decade due to increase in the controlled and uncontrolled deforestation in South America (Setzer et al. 1988; Malingreau and Tucker 1988), and due to an increase in the area of cultivated land with the expansion of population in Africa and South America (Seiler and Crutzen 1980; Houghton et al. 1987). In the burning process trace gases and particulates are emitted to the atmosphere, and the ability of the earth to fix CO2 is substantially reduced (17% of the primary productivity occurs in the humid tropical forests — Atjay et al. 1979; Mooney et al. 1987), and as a result has a strong contribution to the anticipated climate change (Houghton and Woodwell 1989).

Remote Sensing of Biomass Burning in the Tropics

Measuring the aerial extent of tropical deforestation for other than localized areas requires the use of satellite data. We present evidence to show that an accurate determination of tropical deforestation is very di A cult to achieve by a ' random sampling' analysis of Landsat or similar high spatial resolution data unless a very high percentage of the area to be studied is sampled. In order to achieve a Landsat-derived deforestation estimate within O 20% of the actual deforestation amount 90% of the time, 37 of 40 scenes, 55 of 61 scenes and 37 of 45 scenes were required for Bolivia, Colombia and Peru respectively.

Strategies for monitoring tropical deforestation using satellite data.

The distributions of forest and deforestation throughout the tropics are poorly known despite their importance to regional biodiversity and global climate and biodiversity. Deforestation estimates based on surveys or sampling have large errors, and high-resolution, wall-to-wall mapping of tropical forests is necessary to assess the impacts of fragmentation. Landsat satellite images from the mid-1980s and early 1990s were thus used to map closed-canopy tropical forest extent and anthropogenic deforestation in an approximately 700 000 km 2 area of Amazonian Bolivia with precipitation >1000 mm yr -1 . Total potential forest cover extent, including tropical deciduous forest, was 448 700 km 2 , while the area of natural non-forest formations was 245 100 km 2 . The area deforested was 15 500 km 2 in the mid-1980s and 24 700 km 2 by the early 1990s. The rate of tropical deforestation in the forest zone of Bolivia with >1000 mm yr -1 precipitation below 1500m elevation and north of 19° S, was 1529 km 2 yr -1 from 1985-1986 to 1992-1994. Our estimates of deforestation are significantly lower than those reported by the Food and Agriculture Organization of the United Nations (FAO). We document a spatially-concentrated 'deforestation zone' in Santa Cruz where >60% of the Bolivian deforestation has occurred. These results indicate that the rate of deforestation in Bolivia has been rapid despite a relatively small human population, and, as in Brazil, clearance has concentrated in the more deciduous forests.

/pdf/tropical-deforestation-in-the-bolivian-amazon-12dzupa1tq.pdf

Compton J. Tucker

Papers

Fifty years of deforestation and forest fragmentation in Madagascar

NASA’s Global Orthorectified Landsat Data Set

Remote Sensing of Biomass Burning in the Tropics

Strategies for monitoring tropical deforestation using satellite data.

Tropical deforestation in the Bolivian Amazon