Floristic changes following the chestnut blight may be delayed for decades

A survey conducted in the 1920s, prior to the chestnut blight, indicated that chestnuts and oaks were codominant canopy species in White Oak Canyon, Shenandoah National Park, Virginia. A second survey in 1977 suggested that chestnuts were being replaced by tree species present before the blight, particularly oaks. In 2021, we resurveyed the 10 sites included in our 1977 survey and also recorded canopy and understory trees that grew above remnant chestnut sprouts. The canopy changed more substantially during the second interval (since 1977). Birch and maples were now more abundant. Hemlock declined, and oaks were less common in the canopy. In general, the trees considered as early to mid-successional have replaced oaks and hemlock. Chestnut sprouts have become much less common since 1977, presumably as repeated cycles of diebacks have weakened rootstocks. Those sites where chestnut sprouts have persisted until 2021 differed from neighboring sites without them. Chestnut sprouts were rare in sites with birch and hemlock; chestnut has persisted in locations with red oaks in the canopy and with few other understory competitors. This survey has been conducted over a longer time interval than previous studies that asked similar questions and our results suggest that changes to the forest composition following the loss of the American chestnut may be greater than previously recognized although the relative contribution of losing this codominant species is unclear.