Abstract: The high sensitivity of ectomycorrhizal fungi to the changes in the vegetativecondition of the plants makes them suitable to be used as bio-indicators in healthy monitoringprograms of forest ecosystems. For this purpose, general predictive models concerning therelationship between tree health and ectomycorrhizal fungi are need. The building of suitablemodels requires large-scale studies in order to explore the different situations were forest speciesgrow. Considering such aim this research on the cork oak ectomycorrhizal communities is carriedout in Sardinia. In addition to health state of trees two key factors (soil type and forest structure)influencing the qualitative-quantitative composition of the ectomycorrhizal community are alsoconsidered. In this note the experimental approach and its effectiveness in revealing the richnessof species of cork oak ectomycorrhizal fungal community is discussed.