THE ECTOMYCORRHIZAL COMMUNITY IN A <em>PINUS</em> <em>OAXACANA</em> FOREST UNDER DIFFERENT SILVICULTURAL TREATMENTS

Abstract

Valdés M, Pereda V, Ramírez P, Valenzuela R & PINEDA RM . 2009. The ectomycorrhizal community in a Pinus oaxacana forest under different silvicultural treatments. This study was conducted in a tropical mountain ecosystem to examine the ectomycorrhizal (EM) fungal communities in a secondary pine-oak forest under different silvicultural practices. Species richness was analysed by examining ectomycorrhizal root tips and sporocarps in a control, seed tree harvest and seed tree harvest plus prescribed burning stands. The fungal region ITS1-5.8S-ITS2 from single EM root tips was digested and compared with the ITS-RFLP of identified sporocarps of the same stands. Diversity of EM fungi was higher in terms of ITS-RFLPs for root tips compared with sporocarps. Fungal abundance was slightly affected by silvicultural treatments, but species composition was different. Fruiting bodies of Laccaria laccata and Lactarius crysorrheus were most abundant in all stands. Sporocarps of Russula emetica, L. laccata, L. chrysorrheus and sclerotia of Cenococcum geophilum were found in all three stands. However, L. laccata and L. chrysorrheus were found just in the roots of trees growing in the burned stand. Cenococcum geophilum was present in all stands. The seed tree treatment had the highest numbers of the root colonizing fungi as well as EM sporocarps, i.e. 24 RFLP-taxa and 30 sporocarp species, whereas the control stand had 19 RFLP-taxa as EM and 12 sporocarp species. Thirty five per cent of the identified sporocarp taxa were found in the roots. Thus, the seed tree treatment preserved the vital symbionts of the trees best.