Anomalous earlywood vessel lumen area in black ash (Fraxinus nigra Marsh.) tree rings as a potential indicator of forest fires

Earlywood, latewood, total ring width and cross-sectional earlywood vessel lumen areas were measured in twenty-one Fraxinus nigra trees located in the southern boreal region of Quebec, Canada. Two of the trees survived a severe fire in 1923 during which year almost no latewood was produced. In 1924 both trees produced rings with a strong decrease in the size of the largest earlywood vessels. This synchronized size decrease in cross-sectional earlywood vessel lumen area was not observed in other years and is likely a response of the trees to either direct injury or changes in environmental conditions associated with fire. Vessel characteristics in ring-porous species have the potential to be used in conjunction with other indicators of fire to extend fire history reconstructions on a spatial scale.