Mechanical thinning was carried out in two experiments in Range Management Nursery, Pakistan Forest institute, Peshawar for estimation of biomass of fodder tree species during December, 1991 to January, 1992. Selective parameters of growth of all the sample trees of different fodder tree species were measured. Green weight of stem wood, branch wood, leaves and pods were recorded separately for biomass calculation. Dry weight after 6 weeks was also measured. The results showed that 12 years old Ceratonia siliqua yielded the highest amongst all fodder trees. Its total biomass per plant was 184.4 kg, and was followed by Acacia tortilis, which yielded 80.3 kg. per plant.