The Fungal Community Associated With An Arboreal Histosol In a Redwood Tree (at 51 m height), Del Norte County, CA.

Our objectives were to identify the species composition of mycorrhizal symbionts of Polypodium scouleri (leather fern) and other fungi to gain a better understanding of nutrient cycling and characterization in arboreal soil mats. Leather fern is the most abundant vascular epiphyte in old-growth redwood rain forest canopies, where it forms large soil accumulations (Histosols). Little is known about the fungal communities of these epiphyte mats.  Samples from a 150-cm-deep histosol beneath a giant fern mat were obtained at four depths from just beneath fern fronds and rhizomes all the way to bark surface (i.e., 10, 50, 100, and 150 cm). Tiers were differentiated based on decomposition level of leather fern roots and redwood leaf litter. Ten samples of DNA were extracted and evaluated using primers ITS4, ITS-1F to determine 18sRNA sequences. Three fungal groups were identified: Heliotales, Ascomycota, and an uncultured soil fungus. The uncultured soil fungus was reported from northern temperate forests. The Ascomycota has been reported in association with Rhododendron, a common genus in redwood ecosystems. Heliotales has been reported as a root fungus, however little additional information is known. Further research may involve deliberate dissection of fresh leather fern roots to obtain a more direct identification of mycorrhizal symbionts, with the three entities described above as putative symbionts.