source: http://www.montana.edu/wwwpb/pubs/mt8405.htmlAs the wood surface temperature rises beyond 212° F to about 450° F, major gases abundant in creosote are produced: carbon dioxide, carbon monoxide and acetic and formic acids. <<<SNIP>>> The process by which gases are released from wood and burned is called primary combustion. Primary combustion begins at about 540° F, continues toward 900° F