The successful development of early stages of blight-resistant hybrid stock has increased hopes for restoration of American chestnut (Castanea dentata) to eastern North American forests. However, these forests have undergone substantial ecological change in the century since the functional extirpation of American chestnut, and it remains unknown to what extent American chestnut will be able to recolonize contemporary forests. In particular, high densities of white-tailed deer (Odocoileus virginianus) and competition with mesophytic tree species such as maple (Acer) may impede chestnut regeneration, much as they affect oak (Quercus). We used a split-plot analysis of variance (ANOVA) design to examine the effects of canopy gaps and herbivory on survival and growth of third generation backcrossed (BC3) hybrid chestnut seedlings over two growing seasons in central Indiana, U.S.A. Only 4 of 588 (0.7%) seedlings in closed-canopy plots survived to the end of the study, as opposed to 264 of 589 (45%) seedlings in gap plots. Within the gap treatment, fencing was associated with reduced chestnut survival as well as reduced herbivory and increased cover of non-chestnut vegetation. Our results indicate that herbivory may indirectly benefit chestnut regeneration by suppressing competition. However, this beneficial effect is likely context-dependent and additional work is needed to establish the conditions under which it occurs.
