Pyrography or pyrogravure is the art of decorating wood or other materials with burn marks resulting from the controlled application of a heated object such as a poker. It is also known as pokerwork or wood burning.
 

The term means "writing with fire", from the Greek pur (fire) and graphics (writing). It can be practiced using specialized modern pyrography tools using a metal implement heated in a fire, or even sunlight concentrated with a magnifying lens.
 
Pyrography is also popular among gourd crafters and artists, where designs are burned onto the exterior of a dried hard-shell gourd, usually with dramatic results.
(Wikipedia)