Fire and Recruitment of Quercus in a Postagricultural Field

-We investigated the relation between fire and oak recruitment in a mosaic of grassland and forest communities in S-central Iowa. Fire caused high ramet mortality, but low genet mortality among oaks ?50 cm in height. In addition to increased sprouting, fire promoted terminal dominance in oak ramets and more vigorous height growth. This vigorous height growth resulted in a larger proportion of stems in the >50-cm height class at the end of the study in the burned areas compared to the unburned area. The patterns of recruitment during our 4-yr study included 1 yr of high recruitment followed by 3 yr of low but steady recruitment. Annual variation in oak recruitment proved to be statistically significant, but differences in recruitment rates between burned and unburned areas were not significant. On average, recruitment rates for oak were low in our study area, but mortality rates were also low on this dry, S-facing slope. Quercus was neither a rapid colonizer nor necessarily a rapid grower during its early development on the site. It can be best characterized as persistent with its opportunity for establishment enhanced by fire.