Forest above-ground Biomass estimations
Forest above-ground biomass, USA 2011 (Source: Woods Hole Research Center)
Determination of forest biomass has become increasingly important in line with climate change issues and reduced emissions from deforestation and degradation (REDD and REDD+) activities. EO data have become an important data source especially for determining above-ground forest biomass estimations.
Many methods are used to estimate and map forest biomass from EO data, depending on the input data available. Significant progress has been made in recent years regarding the application of EO for the mapping of forest biophysical attributes, such as tree cover density, tree height, and forest type (species), over large-areas. Based on these products it is possible to estimate above-ground biomass, measured in tons per hectare.
Other EO techniques use radar to penetrate into the forest canopy to derive information on stem volume. Stem volume can be related to above-ground biomass and carbon stock by calibrating and correlating with in situ data from forest inventories. Vegetation indices (NDVI and LAI) from optical sensors can also be used to improve biomass estimations.
Information and accurate characterization of variability and trends in forest biomass at local to national scales is required for accounting of global carbon sources and sinks and monitoring their dynamic. Furthermore, maps of aboveground biomass and carbon stocks are valuable in the supporting of biodiversity conservation activities.
This product delivers maps or raster digital files that delineate and identify:
EO biomass estimations are anticipated to improve with the launch of the ALOS-2 satellite which allows for more timely estimations of forest changes. ESA is also developing the Biomass Earth Explorer mission.
Known restrictions / limitations
In tropical rain forest areas, frequent cloud cover can be an issue for the production of optical imagery. Furthermore, the availability of VHR1 data must be ensured for the generation of density samples.
Tree height information is a standard parameter used to calculate biomass. It is possible to estimate canopy height using optical stereo data or a combination of optical (single image) and radar (stereo image). If optical stereo data for generation of DSM, DTM and nDSM are used, the effects of clouds, cloud shadows as well as shadow areas caused by terrain must be accounted for to prevent the omission of elevation information.
Lifecycle stage and demand
Pre-Licensing & Exploration:
Development, Production & Decommission:
Geographic coverage and demand
Globally in forested or densely vegetated areas.
HC:4104 Mapping of forest extent and quality for environmental baseline and/or impact assessment
Input data sources
Optical: VHR1, VHR2, HR1, HR2
Radar: VHR1, VHR2, HR1, HR2
Spatial resolution and coverage
Spatial resolution: 1 - 30 m pixel size resampled to 25 – 50 m grid
Minimum Mapping Unit (MMU)
n/a (the product is directly based on the input data; the smallest unit is one pixel)
Accuracy / constraints
Thematic accuracy: n/a
Spatial accuracy: The goal would be one pixel, but it depends on reference data
Accuracy assessment approach & quality control measures
Comparison of confidence intervals for the estimates against field data following the standard UNFCCC approach - good practice guidance.
Frequency / timeliness
Observation frequency: The frequency is constrained by satellite revisit and acquisition timeframes and also the processing requirements. Depending on the requirements of the customer the most suitable satellite sensor has to be selected, considering spatial / spectral resolution as well as revisit frequency. Typically, long-term changes are detected on a 3 to 5 year basis (frequency can be lower or higher depending on demand).
Timeliness of deliverable: This varies with size of the mapped area and resolution required. Initial product outputs can be derived quickly (1 – 2 days). Analysis, modelling and mapping require more time (2 – 4 weeks).
VHR1 and VHR2 data must be commercially acquired. If spectral-based data is used, large MMU methods, Landsat-8 etc. are appropriate. For example forest biomass was measured in Canada with 1 km AVHRR for many years.
Delivery / output format
|Peer Reviewer:||Hatfield Consultants|
Maria Lemper, Jan Militzer
Forest above-ground Biomass estimations
# of Pages:
Internal – Project consortium and science partners
External – ESA
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