Most recently a Mr. S. A. Channiwala 1992 thesis, The Indian Institute of Technology, Bombay) collected data on over 200 species of biomass and fitted the following equation to the data:
HHV (in kJ/g) = 0.3491C + 1.1783 H - 0.1034 O - 0.0211 A + 0.1005 S -0.0151 N
Where C is the weight fraction of carbon; H of hydrogen; O of oxygen; A of ash; S of sulfur and N of nitrogen appearing in the sltimate analysis.
This equation fitted the experimental data with an average error of 1.45%, typical of the error of most measurements. This equation permits using heat values in calculations and models of biomass processes.
However, I am giving here the table for fuels indicating their ultimate analysis & HHV.
Source: - BioMass Energy Website