It is deep beneath the bark, the spark: waiting. Something has contrived to put it there, in case of emergency.
There is a day when the flames come. The tree is fuel, a friend to the fire; letting it climb into the sky, tickle the orange clouds. The tree is eaten by fire and spat upon the ground. Branches are bitter crumbs; leaves breathed out in hot heaves, borne off upon the breeze. Now there is no ladder between earth and cloud.
The spark survives. It seeds another tree, in time, and the song of wood and flame begins again.