In seasonally dry climates oaks are often fire-resistant , particularly in open grasslands , as a grass fire is insufficient to ignite the scattered trees . In contrast , a eucalyptus forest tends to promote fire because of the volatile and highly combustible oils produced by the leaves , as well as the production of large amounts of litter high in phenolics , preventing its breakdown by fungi and thus accumulating as large amounts of dry , combustible fuel . Consequently , dense eucalypt plantings may be subject to catastrophic firestorms . In fact , almost thirty years before the Oakland firestorm of 1991 , a study of eucalyptus in the area warned that the litter beneath the trees builds up very rapidly and should be regularly monitored and removed . It has been estimated that 70 % of the energy released through the combustion of vegetation in the Oakland fire was due to eucalyptus . In a National Park Service study , it was found that the fuel load ( in tons per acre ) of non-native eucalyptus woods is almost three times as great as native oak woodland
Oakland firestorm of 1991
Oakland firestorm of 1991
Eucalyptus