COMBUSTIBILITY OF FRESH LEAVES OF 26 FOREST SPECIES IN CHINA

In subtropical evergreen forest in East China, forest fires cause huge economic losses. Flammability of fresh leaves can play an important role in determining fire spread. Therefore, a study on the influence of fire on evergreen trees is of great importance to investigate the ecological properties of forest fire and protection of tree species. The combustibility of fresh leaves of 26 dominant evergreen plant species in East China were compared and suitable species for use as fire-resistant tree species were recommended. Using the cone calorimeter, variations of 12 burning parameters through time were described. The principal components affecting combustibility of fresh leaves were smoke, heat and time. Most burning characteristics were correlated with heat. Based on thermal—calorimetry analysis and smoke spread test data, 17 species were slow combustible species, with relatively longer ignition delay time, lower heat release rates and peak of heat release rate, longer time to peak of heat release rate, less total heat release and higher smoke production. All results indicate that species which have higher release of total smoke will have lower heat release rate. Thus, less flammable species are recommended to be used as fire-resistant tree species and in the construction of renewed forest. Kebakaran hutan di hutan malar hijau subtropika di China Timur menyebabkan kerugian ekonomi yang besar. Kemudahbakaran daun segar boleh memainkan peranan penting dalam perebakan api. Oleh itu, kajian kesan api terhadap pokok malar hijau penting untuk meninjau ciri ekologi kebakaran hutan dan perlindungan spesies pokok. Keterbakaran daun segar 26 spesies pokok malar hijau yang dominan di China Timur dikaji dan spesies yang sesuai disyorkan sebagai spesies pokok tahan kebakaran. Variasi 12 parameter kebakaran dengan masa dihuraikan menggunakan kalorimeter kon. Komponen utama yang mempengaruhi keterbakaran daun segar ialah asap, haba dan masa. Kebanyakan ciri kebakaran berkorelasi dengan haba. Berdasarkan analisis haba—kalori dan data perebakan asap, 17 spesies didapati terbakar dengan lambat. Secara perbandingan, spesies ini mempunyai masa menyala yang lambat, kadar pembebasan haba yang rendah, puncak kadar pembebasan haba yang rendah, masa yang lama untuk mencapai puncak kadar pembebasan haba, jumlah pembebasan haba yang rendah dan penghasilan asap yang tinggi. Semua keputusan menunjukkan bahawa spesies yang mengeluarkan asap yang banyak mempunyai kadar pembebasan haba ya