FLAMMABILITY STUDIES OF SOME FIRE TOLERANT TREES OF SOUTH-EAST, NIGERIA
Bush fire is a common hazard in South Eastern Nigeria as in other parts of the country during the harmattan. Every year, thousands of hectares of forests as well as suburban lands are severely burnt. These forest fires have been catastrophic, destroying large areas of tropical rain forests. However, some trees in these forests have proven to be fire resistant. These tree species were identified by local people. Flammability studies of fifteen of these fire tolerant trees of South Eastern region of the country were carried out with a view to encouraging their use in afforestation. The flame characteristics, viz., ignition time, flame propagation rate, after glow time, flame duration, char formation, and limiting oxygen indices of these tree species were carried out. In addition, physical properties such as densities and moisture contents were evaluated in order to determine their effects on their burning parameters. The values for these parameters vary among the selected tree species. Density in particular, related to the ignition and flame spread behaviours, although, for the denser hard woods above 0.50g/cm3 and this dependence is less straight forward. Attempts were made to explain these observations on the basis of thermal conductivities, cellular structures, and presence of special flame resistant pyrolysates at flaming temperature.