Add Global Biomass maps

[saranda-2811]

Estimation of biomass using satellite data (GLAS lidar) is done here. Refer to the "supporting information" for more data.

The below paper clearly explains how the lidar data is obtained and there's data on AGB in different countries. It also gives data on carbon stocks.
pnas.201019576si.pdf
st02.docx

Here's another helpful paper. Refer to the supplementary material for more data.

[saranda-2811]

Combining satellite lidar, airborne lidar, and ground plots to estimate the amount and distribution of aboveground biomass in the boreal forest of North America