Fire in the Venezuelan Amazon 1: fuel biomass and fire chemistry in the evergreen rainforest of Venezuela

Total surface fuel biomass which consisted of the root mat, litter layer, and downed woody materials ranged from 13 t ha^-1 in an open canopy, low stature upland forest type (Bana) to 253 t ha^-1 in a floodplain forest type (Low Igapo). Most of the fuel biomass was composed of the root mat and large (>7.6 cm diam.) woody debris. Chemical contents of vegetation may play an important role in fire behavior. Energy contents of fuels affect fire severity while compounds in the ash content may act as flame retardants. The energy content, total ash and acid insoluble ash fractions of litter layers and individual plant species varied greatly among communities. Energy content (gross heat of combustion) of the leaf litter layer ranged from ~19 000 to 25 000 kJ kg^-1. Forest floor litter ash content varied from 0.8-7.7% and acid-insoluble ash varied from 0.4-6.2. -from Authors