What ignites during Stage III of wood combustion?

During Stage III of wood combustion, hydrocarbon gases and tar droplets ignite due to the increasing temperatures and decreasing moisture content within the burning wood. At this stage, the solid components of wood have been mostly converted into gases and vapors as heat continues to rise and the combustion process advances.

The ignition of hydrocarbon gases and tar droplets signifies that the gasification process has reached a point where the byproducts of incomplete combustion are finally igniting, contributing to a more complete combustion. This results in a significant increase in heat and flame production, as these gases are highly flammable and essential for achieving a well-established fire.

Understanding this phase of combustion is crucial for effectively managing wood-burning appliances, ensuring efficient energy use, and minimizing emissions, as the ignition of these gases is indicative of a proper burn cycle.