The objective of this study is to determine the above ground plant biomass of the Mogi-Guaçu river gallery forest and to identity the best equation to predict the above ground tree biomass. This study was carried out in a remaining fragment of mesophyllous forest, located in Itapira, São Paulo (22(0)21'S and 46(0)51'W). Twelve plots of 25 m² were established to determine the above ground plant biomass by destructive method. Trees were identified and cut down at ground level. Each tree had its height and basal perimeter registered. Leaves and woody material were manually separated and the fresh weight for these two fractions was determined. Herbs and shrubs lower than 1.3 m height in a 3 m² of each plot were cut down at ground level and fresh weight of the woody and non-woody fractions was also determined. The same procedure was used to evaluate the biomass of lianas. Samples of each fraction were dried at 80(0)C to constant weight the determine the dry weight. The total phytomass estimated for the forest was 133.3 t/ha. The tree layer accounted for 88.5%, and lianas and herbs for 11,3% and 0.2%, respectively. The best equation to predict tree biomass in similar forests is: Total tree biomass = [ 0.523 + 0.053 perimeter]³.
Allometry; biomass; gallery forest