Herbivory and fire influence white oak (Quercus alba L.) seedling vigor

We manipulated arthropod and mammalian herbivory levels on white oak seedlings using a combination of insecticide applications and fencing and employed a split-split-plot design to assess the impact of single- and multiple-year burns on seedling growth over a 2 yr period. Herbivory levels increased over time on all sites, but there was no significant difference in herbivore pressure on seedlings in single-year burned, multiple-year burned, and nonburned plots. Insecticide-treated seedlings suffered less herbivore pressure than did noninsecticide treated seedlings, and mammalian herbivory was significantly reduced by the presence of a fence. Seedling height growth, shoot elongation, diameter growth, and specific leaf mass were greatest on once-burned sites, intermediate on twice-burned sites, and least on nonburned sites. Bud expansion was the only seedling performance parameter unaffected by burn treatment. Arthropod feeding was the greater component of overall herbivory, but this herbivory did not impede seedling growth. Seedling height growth and shoot elongation were more closely linked to mammalian herbivory. These results suggest that the observed herbivory may play a negligible role, and prescribed fire may be a beneficial component of a management program designed to enhance oak regeneration.