Combustion experiments were performed over a flat-flame burner that provided the heat source for multiple leaf samples. Interactions of the combustion behavior between two leaf samples were studied. Two leaves were placed in the path of the flat-flame burner, with the top leaf 2.5 cm above the bottom leaf. Local gas and particle temperatures, as well as local oxygen concentrations, were measured along with burning characteristics of both leaves. Results showed that the time to ignition of the upper leaf was not significantly affected by the presence of the lower leaf. The major difference observed was that the time of flame duration of the upper leaf was significantly affected by the presence of the lower leaf. Causes for the prolonged flame were found to be the consumption of oxygen by the burning lower leaf and the obstruction provided by the lower leaf, causing a wake effect, thus altering the combustion behavior of the upper leaf.
Pickett, Brent M.; Isackson, Carl; Wunder, Rebecca; Fletcher, Thomas H.; Butler, Bret W.; Weise, David R. 2009. Flame interactions and burning characteristics of two live leaf samples. International Journal of Wildland Fire. 18: 865-874.