Reclamation of an abandoned burned forest using ectomycorrhizal inoculated Quercus rubra

It is recognized that inoculation with ectomycorrhizal (ECM) fungi can have a positive effect on the establishment of nursery grown seedlings and influence their survival during the first years. However, an increased effort is needed to understand their role and behavior in abandoned burned areas. We investigated tree performance of pre-inoculated Quercus rubra seedlings on a site with fire history and monitored fungal persistence and succession dynamics of the ectomycorrhizal community established. Nursery grown Q. rubra seedlings inoculated with a mixture of 6 ECM fungi (Cenococcum geophilum, Hebeloma crustuliniforme, H. mesophaeum, H. velutipes, Paxillus involutus and Scleroderma citrinum) were transplanted to Serra da Cabreira, Northern Portugal. Non-inoculated control oak seedlings were also transplanted. Two years after planting, biometric and mycorrhizal parameters were determined. The presence of the inoculated ECM fungi and the dominant ECM fungal community established was assessed by DGGE-cloning. Results showed that the bioinoculants improved the growth performance of outplanted oak seedlings, promoting a c.a. 1.6-fold increase in height and a 2.9-fold increase in the number of ECM root tips. After two years, H. mesophaeum, H. velutipes, P. involutus and S. citrinum persisted in the root system of inoculated plants. Ordination analysis demonstrated that ECM fungal communities of inoculated and non-inoculated samples were significantly different. The present work reinforces the benefits of using nursery inoculated plants in forest reclamation processes.