Abstract
Results of field investigation of some forest fires in Japan are described :
1) It is known that the one-side burning of trunks of timber stand indicates the direction of the spreading flame or wind there. Making use of this phenomenon for the field investigation of forest fires, it is shown that the suppression at the leeside of the mountain was successful where the topographic or convectional wind direction was opposite to the spreading of the flame.
2) The spreading speed of forest fires are estimated on some cases amounting to about.
3) It is confirmed that the burning barked skin of the trunk of Cryptomeria Japonica leaped and made secondary fires in other places.
