Excluding deer increases the proportion of beech saplings originating from seed versus those of root sprout origin

Abstract

Abstract American beech (Fagus grandifolia Ehrh.) regenerates both from seed and also clonally via root sprouts. Regenerating beech saplings often form dense and depauperate understories that cast deep shade and displace co-occurring species. The relative proportion of saplings that originate from seed versus root sprouts varies widely throughout the range of beech. Although the cause for that variation remains unclear, it may be linked to canopy or soil disturbances, the spread of beech bark disease (BBD), or overabundant deer. Here, we asked whether the long-term exclusion of deer and the absence of BBD would favor the regeneration of saplings (20–150 cm tall) of seed origin versus those of sprout origin. We addressed this question using deer exclosures (16 and 60+ yr old) and paired controls in one forest in Pennsylvania where BBD had caused major adult mortality and another where BBD was not present. We found that excluding deer significantly decreased the relative proportion of root sprouts from appr...