Forests are multi-faceted natural resources. They are valuable sources of industrial wood and fuel, but they also play many other important roles.
They are significant as sites of rich biodiversity, bulwarks against soil erosion, modifiers of local climate and stores of carbon - as well as often serving as important recreational features and tourist attractions.
The sustainable management and exploitation of forest systems for the long term requires balancing all these different roles, a difficult task made simpler by the ability to obtain regularly-updated views of how they change over time.
This is no easy task: despite extensive deforestation during the last century, forests still cover almost a third of global land surface area.
However Earth observation can provide the information required, with the potential to capture entire forests in a handful of acquisitions. Satellites have a proven ability to identify forest boundaries and distinguish between different tree species and biomass density and health.
Land-cover change maps derived from satellite imagery can show forested areas undergoing logging as well as land clearances, burn scars, secondary growth, settlement and agriculture.
Illicit intrusion onto forested areas can be swiftly highlighted, and forest managers can also use these maps as information tools to update their inventories, limit logging to sustainable levels while monitoring the success of reforestation efforts.
Such maps and associated information products also serve as hard evidence of national compliance with international treaties concerned with forests, such as the Kyoto Protocol and the Convention on Biological Diversity.