Fire Safety Science Digital Archive

The stands of P. yunnanensis and P. kesiya Yar. Jangbianesis less than 8-11 years cannot be under burned and those of 8-11 years must be pretreated once by thinning before under burning practice according to their growth Process. The stands over 15 years can be under burned at the frequency of 1-4 years/ time depending on the closure of the stand and the load of fine fuel under the crown. It is suggested that the factors involving the prescription be divided into two groups--the influential ones and the limiting ones depending on their importance to the under burning. The emphasis is laid on the unified effects of all factors on the under burning. A prescription of under burning of the two species suitable to the climate and geography of Yunnan and proper method of operation and crew organization are given in this paper.