Planting stock type and seasonality of simulated browsing affect regeneration establishment of Quercus rubra

Animal herbivory is a major limiting factor to successful oak (Quercus spp.) regeneration. Although bare-root seedlings are the most commonly used nursery stock type for oak plantings in the eastern United States, container seedlings may better resist planting stress and help enable seedlings to overcome browsing pressure. Four stock types (1 + 0 bare-root seedlings and seedlings in 164, 336, and 520 mL containers) of northern red oak (Quercus rubra L.) were planted on two reforestation sites in Indiana, USA, which were fenced to exclude white-tailed deer (Odocoileus virginianus Zimmerman). Seedlings were then subjected to three simulated browsing treatments (control unclipped, dormant clipped, and summer clipped). Container seedlings exhibited higher relative growth rates on both sites; for example, at one site, control seedlings in 336 mL containers had relative height growth of 558% compared with 79% for bare-root control seedlings. On both sites, summer-browsed seedlings of all stock types had negligible height growth, and summer browsing reduced survival at one site by 23% for all stock types compared with control seedlings. Browsing of seedlings during the dormant period did not affect growth for any stock type. Container seedlings may help facilitate rapid establishment of planted oak seedlings, but browse protection is necessary to ensure oak regeneration success in areas of large populations of deer.