Area burned by wildfires in Arizona and New Mexico. Annual area burned by wildfires in Arizona and New Mexico on all lands (state, private and federal), 1916 to 1996. The increased area burned in the late-20th century has been most commonly attributed to accumulated living and dead forest fuels since fire suppression began early in the century. However, wetter conditions since the 1970s might also be involved, particularly in ecosystems where plant productivity is ordinarily low, and grasses have increased in importance. Fine fuels, such as grasses and leaves, may be a key factor in these seasonally dry ecosystems where fuel continuity is limiting to fire spread. Expansion of non-native grasses in some parts of the Southwest may also have contributed to this pattern.