BURNING TEMPERATURES OF GRASSLANDS IN JAPAN : (3) CONDITION OF FUEL BEFORE AND AFTER BURNING IN GRASSLANDS

Abstract

IWANAMI, Yuuki (Institute for Agricultural Research, Tohoku Univ.) Burning temperatures of grasslands in Japan. (3) Condition of fuel before and after burning in grasslands.Jap.J.Ecol. 21,246-254 (1971) Described are the condition of fuel before and after burning in grasslands situated in the suburbs of Sendai (Kawatabi, south Zao, Sakunami and so on). In the Zoysia type, Miscanthus type and Sasa type grasslands, the amount of fuel before burning was 0.2-0.6,0.25-1 and 1-3 kg/m^2,respectively. In the Miscanthus type grassland, according to whether the dead grass is lying on the ground by the accumulated snow, the type of vertical distribution of the fuel can be classified into two classes, i.e. (1) "Standing dead type" and (2) "Push down type". The disposition of fuel of the Zoysia type grassland belongs to the "Push down type", and that of the Sasa type grassland to the "Standing dead type". In the field fire or burning, it is necessary that the water content in the fuel is low for the fuel to burn well. Generally speaking, the standing dead of Miscanthus burnt well when the water content was less than about 50 per cent. However, that of the "Push down type" sometimes failed to be burnt even when the water content was less than 30 per cent, because evaporation from the fuel was difficult. In the Miscanthus type and the Sasa type grasslands, it was easy to burn 90 per cent or more of the entire fuel. On the other hand, in the Zoysia type grassland, even when it seemed to be burnt quite well, 35-73 per cent of the fuel amount was left unburnt.