Estimate of total biomass is incorrect. 

The page defines biomass as:

"Biomass is organic non-fossil material, collectively. In other words, 'biomass' describes the mass of all biological organisms, dead or alive..."

and then goes on to state:

"The entire earth contains about 75 billion tons of biomass."

Assuming 1 billion is 10^9, this estimate is too low to be consistent with the definition.

To give an example, in its "Global Forest Resources Assessment 2000", the FAO estimates that the "global total above-ground woody biomass was 422 billion tonnes"

(http://www.fao.org/documents/show_cdr.asp?url_file=/DOCREP/004/Y1997E/y1997e01.htm).

David Wardle.