Satellite data are invaluable for mapping India's remaining forests, but their coarse resolution limits the information they can provide for protection purposes (Nature 489, 14–15; 2012).
For example, individual tree species cannot be identified from satellite data. This encourages selective felling of valuable trees, such as teak, while green cover is maintained to avoid satellite detection. Also, remotely sensed data do not reveal areas where local communities have a close relationship with the forests, as in India's Meghalaya hills.
Mobilizing citizens to provide information on the ground ('crowd sourcing') complements remote-sensing data. Using devices such as mobile phones (see www.geo-wiki.org), this approach provides a means to report illegal logging, catalogue trees that need protection because of their cultural, ecological or economic importance, validate spatial forest data and quantify forest degradation. It also raises awareness and informs public debate on sustainable forest management. In Brazil, for example, citizens have used the Globo Amazônia website since September 2008 to log millions of complaints against illegal activities as a cause of deforestation (see www.globoamazonia.com).
The controversy over India's forest resources is worrying, but it points to an emerging transparency in governance that allows people's concerns to be voiced. Crowd sourcing would enhance this transparency while improving the quality of data.