Ectomycorrhizal Community Development in Hardwood Restoration on Coal Mined Landscapes.

Anthropogenic disturbances such as mining for coal have caused significant disturbance to the Appalachian forests of eastern North America.  Forest recovery is highly dependent on restoration methods that encourage natural succession of native trees.  Ectomycorrhizal (ECM) fungi are an intricate part of the belowground ecology and act as important drivers contributing to forest tree establishment.  The severe decline of these microbes due to soil disturbances during coal extraction and subsequent reclamation may contribute to the high mortality of directed tree plantings used in forest restoration.  This current study reports that proper site preparation such as deep soil ripping and plow disking increases the association between plant and ECM fungi on a coal mined site in Ohio, U.S.A.  Roots were collected from 120 chestnut seedlings in 2008 and again in 2013.  ECM genera were determined by fungal DNA sequencing of the internal transcribed (ITS) region, which revealed differences in ECM community composition between the two sampling periods (P < 0.0001).   In addition, certain fungal species were associated with vigorously growing trees, where other ECM species were sampled from seedlings that exhibited significant dieback.   Further, the healthier the tree host, the more ECM inoculum available to chestnuts trees that were planted as seed (P = 0.002).  Chestnut seedlings that germinated from seeds planted in close proximity to healthy trees were significantly larger than those planted close to dying trees (P = 0.04).  This indicates that healthy trees can facilitate the establishment of trees that are actively recruiting into this restoration site as seed.  We suspect that the presence of existing ECM networks facilitated the establishment of new seedlings; however, soil variables are also being evaluated.  Developing management strategies that enhance soil microorganism activity is integral to landscape recovery and the continual succession of trees onto these disturbed sites.