The Influence of ectomycorrhizal colonization on American chestnut trees (Castanea dentata) with regard to growth, fecundity, and susceptibility to chestnut blight (Cryphonectria parasitica).

Ectomycorrhizal fungi (ECM) contribute to the primary productivity and biogeochemical cycling of forest ecosystems. These fungi create symbiotic relationships with plants roots, which allow for the transfer of water and nutrients to the plant and photosynthates to the fungal symbiont. The provision of water and soil nutrients are important for the establishment of seedlings in forest restoration projects. The objective of this study was to understand the relationship between ECM root colonization and tree health in disturbed soils on a reclaimed strip mine. Data were collected from 117, six-year-old trees to assess tree growth, fecundity and the tree’s susceptibility to chestnut blight (Cryophonectria parasitica) regressed by ECM root colonization. Tree growth was measured by tree height (cm) and basal diameter (cm). Fecundity was recorded by counting chestnut burs (fruit) per tree. ECM was measured by percent colonization on root tips. The presence or absence of flowers and chestnut blight (C. parasitica) cankers were also recorded. A simple regression was used to describe the relationship between ECM colonization, with regard to tree growth and bur count. Logistic regressions were utilized to see if ECM can predict the presence of flowers and disease tolerance. The percentage of ECM was not found to be a statistical predictor of the presence of cankers (P = 0.55). ECM was found to be a statistical predictor of flowers (P = 0.044). A statistical difference was found between ECM and tree growth (P = 0.008). These results suggest that the percentage of ECM is associated with tree growth and reproductive fitness, however, whether ECM was the driver remains unclear. ECM colonization does not predict the presence or absence of chestnut blight cankers and appears to not contribute to their ability to deter infection