DOI: 10.5061/dryad.4b8gthtkk
title: Data for: Floristic changes following the chestnut blight may be delayed for decades

description: 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 and species less tolerant of shade were generally
 better represented in the canopy. Hemlock declined, and oaks were less
 common in the canopy. 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.
description: We resurveyed 10 sites in White Oak Canyon in 1977 and again in
 2021. Lucy Braun published a survey of the canopy trees in the canyon that
 she sampled prior to the arrival of the chestnut blight around 1930 (Braun
 1950:225). She did not provide precise sampling locations. In August 1977
 we surveyed 100 randomly selected canopy trees at each of ten
 southeast-facing sites in White Oak Canyon although these are not
 necessarily the same sites that Braun surveyed. We returned to these 10
 sites in 2021 and resurveyed 100 canopy trees at each site.
 In 1977 we surveyed 400 sampling points in White Oak Canyon, 176
 of which had chestnut sprouts. We returned to those sites in 2021 and
 searched for chestnut sprouts or boles. When we located a chestnut sprout
 in 2021 we recoreded the species identity of trees that were growing over
 any part of the space immediately above the chestnut sprout and noted
 whether these other trees reached the canopy or were only in the
 understory. We moved 20m in each of the four cardinal directions from each
 chestnut sprout and recorded the canopy and understory trees above each of
 these points that were taller than 2m.
description: # Data for Floristic Changes Following the Chestnut Blight May Be Delayed
 For Decades ## Description
 of the data and file structure Table 1 shows the frequency of canopy tree
 species in White Oak Canyon (Shenandoah National Park) during Braun’s
 survey that preceded the chestnut blight (roughly 1930) and surveys that
 we conducted in 1977 and 2021. We also include the number of canopy trees
 for the 2021 survey. The letters next to each tree species indicate
 whether that species was classified as early (E), middle (M), or late (L)
 in the successional sequence. Table 2 shows the number of canopy and
 understory individuals that were recorded above chestnut sprouts and above
 the four control points in the vicinity of each chestnut sprout in 2021.