Effect of Modified APP on Flame Retardation Of Fuels of Five Common Tree Species in Daxing’anling Mountains

Fuels （dead branch and leaf） of Pinus tabuliformis var. mukdensis, Larix gmelinii, Quercus mongolica, Juglans mandshurica and Tilia amurensis were collected on August 2014 from Daxing’anling Mountains and treated with modified ammonium polyphosphate （KH-550/APP）. Determinations were made on moisture content, caloric value, ash content and extractive content of untreated fuels and cone calorimeter test was implemented on untreated and treated fuels. The results showed that peak heat release rate, total heat release, total smoke production of fuels treated by modified APP decreased and carbon residue ratio increased. The experiment demonstrated that treated fuels of coniferous trees had better effect than that of broad leaf trees, treated dead branch had better effect than treated leaf.