1 Impact of Fire on Moist Deciduous Forest Ecosystem of Southern Tropical Forests of India A.R.R. Menon, A.O. Varghese and K.J. Martin Lowel Kerala Forest Research Institute, Peechi, Thrissur, Kerala, India-680653,Fax : 0487 - 782247, E-mail : libkfri @ md 2.vsnl.net. in Abstract One of the most complex problems facing in tropical forests, particularly the deciduous forests, is the recurrent incidence of fire. It is well known that fire causes extensive damage in the forest ecosystem by quantitatively as well as qualitatively. In India 75 % of the total forest cover are coming under highly fire prone forest types like moist deciduous, dry deciduous and thorn forests. The main objectives of the present study are to characterise the physical aspects of fire in the moist deciduous forest, to study the changes brought about by fire on vegetation and their regeneration and to explore the feasibility of silvicultural techniques such as stump planting to improve upon fire survival of tree seedlings. The study area is located in the moist deciduous forest of Thrissur forest division, Kerala State, India. Impacts of fire on forests mainly depend on the intensity and periodicity of fire. Hence, to study fire ecological aspects, twelve 0.25ha (50m x 50m) plots were established for different burning treatments, viz. early-burn, late-burn, one year and two year fire frequencies and control, with three replications. Regenerating elements of tree species (1-10cm dbh), shrubs (with height above 50cm and dbh below 1cm) and herbs (below 50cm height) were identified, tagged and enumerated in all plots before and after prescribed burning and compared with the control (no burn) plots. It is observed that once the fuel quantity and fuel moisture content cross a certain limit which is sufficient for occurrence of fire, further change in fire behaviour is controlled by fuel porosity and fuel continuity. Other factors which control the rate of fire spread are size and thickness of leaves, rate of decomposition, soil moisture regime, wind and presence of grasses. The paper elucidates the different aspects of this experiment The results indicate that impact of fire is more in lower diameter classes (1-2.5cm dbh and 2.6- 5cm dbh), whereas regeneration above 5cm dbh is less effected. Among the different moist deciduous tree species, thick bark species such as Gmelina arborea and Pterocarpus marsupium were found to be more resistant to fire. Paper concludes on the possible impact of fire on the status of moist deciduous forests in this part of India. Suhartoyo, H. and T. Toma (eds.) 1999. Impacts of fire and human activities on forest ecosystems in the tropics. Proc. Third International Symposium of Tropical Forest Management, Samarinda, 20-23 September 1999. Tropical Forest Research Center Mulawarman University and Japan International Cooperation Agency, Samarinda, Indonesia. PUSREHUT Spec. Pub. No. 8, 630 p.