Which factor is identified as a burning characteristic of wood?

• A. Size and form
• B. Density
• C. Moisture content
• D. Rate of preheating

Answer: (C)

Moisture content governs how wood behaves in a fire because the water trapped in the wood must be heated and turned into steam before the wood can reach temperatures where it pyrolyzes and ignites. That energy goes into vaporizing water, which cools the material and absorbs heat, delaying ignition and reducing the rate at which flames develop. Higher moisture means more energy is spent on evaporating water rather than producing flammable gases, so ignition is slower and flames are less intense until the wood dries out. Once the wood is dry, ignition becomes easier and burning becomes more vigorous. Other factors like size and form or density influence fire behavior as well, but moisture content has the most direct and significant effect on how wood burns.