Epiphytes on an old Huon pine tree (Lagarostrobos franklinii) in Tasmanian rainforest

The epiphytic flora of an old Huon pine (Lagarostrobos franklinii) in western Tasmania comprises 76 lichens, 55 bryophytes, and 16 vascular plant species. There is a vertical zonation of the cryptogams on the tree, with little overlap between basal and canopy floras. Bryophytes are the dominant life form at the base of the tree but there is a marked increase in the diversity of lichens, and in the ratio of lichens to bryophytes, with increasing height. The longevity of the tree is manifest in the development of a wide range of microhabitats but it seems unlikely that any of the cryptogams require such longevity per se to become established as rainforest epiphytes. However, several of the vascular species on the tree are normally terrestrial and their occurrence as epiphytes is dependent on the development of sufficient peat to support their root systems. Such a process is likely to be very slow, requiring a long-lived host species. The study illustrates the richness of lichens and bryophytes in the forest ecosystem and the extent to which even a single tree can contribute to the biodiversity of a forest site.