3.1. Seedling survival
Chestnut seedling survival averaged 57% after two growing
seasons across the five locations. Canopy treatment had no effect
on seedling mortality (oneway ANOVA; p = 0.905), although
average survival differed widely (26–90%) among the five study
locations. Mortality was highest in the midstory (92%) and
shelterwood (88%) plantings on the Robinson Forest xeric site.
Seedling mortality was also high at a second location (Carpenter
Branch xeric site) that underwent extensive canopy breakage
during a severe windstorm (Fig. 1).
Basal phloem cankers associated with chestnut blight were
present on 23% of the dead seedlings; canker incidence was nearly
two-fold higher on xeric compared to mesic sites (31% vs. 16%,
respectively). Visible symptoms of root disease (i.e., root collar
necrosis or root detachment in the absence of blight cankers)
occurred on 11% of dead seedlings and were twice as common on
deceased seedlings found in shelterwood (15%) compared to
midstory (7%) sites. Eighty percent of all seedlings suffered mild
insect herbivory; severe defoliation that removed the majority of
the photosynthetic surface affected 4% of the seedlings.
Across all sites and aspects, chestnut survival was negatively
related to both sand and coarse fragment content (Spearman’s rho:
0.54, and 0.68 for percent sand and coarse fragment respectively;
p 0.01). Excluding the midstory and shelterwood sites
affected by severe canopy damage, coarse fragment and sand
content explained 46 and 31% of the variability in seedling survival
3.1. Seedling survivalChestnut seedling survival averaged 57% after two growingseasons across the five locations. Canopy treatment had no effecton seedling mortality (oneway ANOVA; p = 0.905), althoughaverage survival differed widely (26–90%) among the five studylocations. Mortality was highest in the midstory (92%) andshelterwood (88%) plantings on the Robinson Forest xeric site.Seedling mortality was also high at a second location (CarpenterBranch xeric site) that underwent extensive canopy breakageduring a severe windstorm (Fig. 1).Basal phloem cankers associated with chestnut blight werepresent on 23% of the dead seedlings; canker incidence was nearlytwo-fold higher on xeric compared to mesic sites (31% vs. 16%,respectively). Visible symptoms of root disease (i.e., root collarnecrosis or root detachment in the absence of blight cankers)occurred on 11% of dead seedlings and were twice as common ondeceased seedlings found in shelterwood (15%) compared tomidstory (7%) sites. Eighty percent of all seedlings suffered mildinsect herbivory; severe defoliation that removed the majority ofthe photosynthetic surface affected 4% of the seedlings.Across all sites and aspects, chestnut survival was negativelyrelated to both sand and coarse fragment content (Spearman’s rho:0.54, and 0.68 for percent sand and coarse fragment respectively;p 0.01). Excluding the midstory and shelterwood sitesaffected by severe canopy damage, coarse fragment and sandcontent explained 46 and 31% of the variability in seedling survival
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