The amount of fungal biomass in boreal forest soil is estimated to be approximately 900 kg ha−1 (Wallander et al., 2001). Considering this amount of fungal mycelia in the soil, it is easily possible that the entire forest ecosystem could be interconnected by a fungal network called the common mycorrhizal network (CMN) (Peter, 2006; Lekberg et al., 2010). The simplest NMC structure consists of one or more mycorrhizal fungi that connect at least two plant root systems. Another possibility is when fungal hyphae fuse together and connect the root systems of their host plants. The two main types of CMNs are AM networks typical of grassland ecosystems and agroecosystems (Helgason et al., 1998), which can originate from mycorrhizal hyphal spindles, and EcM networks typical of forest ecosystems (Selosse et al., 2006). An example, which supports the fascinating wood-wide-web theory, is the study (Beiler et al., 2010) in which it was demonstrated that a single root system of a tree could be connected with 37 other trees via the connection mycelial EcM (Fig 3). From this point of view the whole forest could be a song...