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Land Use Change

According to the European Union’s Renewable Energy Directive (EU RED) biomass is not allowed to be claimed as sustainable when it originates from land that has been converted into cropland after January 2008. Identifying these areas was an unsolved problem within the past years of sustainability assessment.

Land Use Change

Land use change (LUC) verification takes an important role within sustainability certification. The demand for arable land is growing, though land is a finite ressource. Thus, conversion of land for agriculture is regarded as unsustainable. Although LUC could refer to any change it is common sense that it generally describes the conversion of e.g. forest or any other land use category into agricultural land, especially arable land.

However, finding a reliable proof if and when LUC took place is rather difficult. There is no clear evidence on-site that gives hints if a field was converted 20 years or 20 months ago except for local witnesses or official land use documents. Reality shows that a good information source is often either not existing or not reliable.

But technology development of the past years makes it possible to have a good eye witness on-site almost everywhere, almost everytime (at least in high-frequent time steps): Satellites. We can actually see what happened and when it happened. GRAS offers an innovative solution to identify conversion of forest or grassland into agricultural cropland via analysis of up-to-date satellite imagery. GRAS in collaboration with experts from German Aerospace Center (DLR) use state-of-the-art methodology. Together we processed hundreds of gigabytes of remote sensing images from 2000 till today to detect LUC.  Each 3 month we process new gigabytes of images to ensure an up-to-date result of LUC detection.

The methodology is based on detecting LUC from MODIS (Moderate-resolution Imaging Spectroradiometer) greenness index time series (spatial resolution 250m x 250m, temporal resolution: 16 days). The index is called Enhanced Vegetation Index (EVI) with values range from 0 to 1, the higher the values the more green the soil cover is. From one EVI image we can differentiate between bare soil and green cover. From more than 300 EVI images in GRAS we can differentiate among the types of green cover, see the history of the land, and indeed detect LUC. Grassland would look like calm sea waves with minor changes around EVI value of 0.3-0.4 (see picture below). The same would apply for perennial trees such as rain forests but on a higher EVI value of about 0.6 (see second picture below). Conversion would appear as a clear change in those waves with a drop of EVI to a value below 0.2. Arable land used for crops always appears as very regular huge waves (see picture below).

GRAS greenness time series could be used for risk assessment, farm auditing and even for land use change scientific research

However, although EVI can give you the point of time when a change of land use appears it is hard to determine similar land use types, e.g. natural rain forest and palm oil plantation. For a clear identification, GRAS offers a tailored solution that manually analyses high resolution Landsat imagery. GRAS offers this service on demand.

For further information about the development of the GRAS LUC algorithm and EVI time series please read Methodology.

In addition, our partner Genscape Inc. develops an easy-to-use split-screen-tool. The tool makes it possible to conduct a quick visual before-after-evaluation of an area of interest and thus makes land use change visible 1:1. Genscape uses high-resolution aerial imagery (1-2 m) from the USDA (United States Department of Agriculture) National Agriculture Imagery Program (NAIP) from the years 2007 and 2012. GRAS prepares to implement this add-on-tool for USA: