Sunshine filters through Dicksonia antarctica in this photograph that was kindly uploaded by Christopher Young (aka c.young@Flickr) to the Botany Photo of the Day Flickr Pool. Thanks for the summery photograph, Christopher!
Dicksonia antarctica is commonly known as the Australian tree fern, Tasmanian tree fern, hardy tree fern, soft tree fern, as well as the woolly tree fern (it’s a wonder how anyone could know what one’s talking about with so many common names!). As a couple of these names suggest, this species is a native plant to southeastern Australia where it is widespread and common. It grows in fertile, high-rainfall areas in damp, sheltered gullies and (occasionally) higher altitude cloud forests.
Members of Dicksonia have a few identifying characteristics: smooth leaf bases that are covered in rusty-brown hairs (as opposed to scales); fibrous and matted roots that cover much of the trunk; and, marginally-positioned spore clusters. Dicksonia antarctica has a trunk that can reach a height of 15 meters. The trunk is usually solitary, although densely rooted offsets may form with persistent leaf bases towards the crown. The numerous leaves with hairy midribs are borne in a large, spreading crown. Each leaf is divided three times and contains one indusium-covered sorus per lobe.
Dicksonia antarctica is the most abundant tree fern in Australia, though it is in decline. This species is slow growing, only gaining 1-10 cm of height per year. Plants don’t reach maturity until about 23 years. Unfortunately, horticultural demand leans to mature specimens and greenhouse production is too slow, so individuals are typically harvested from the wild for this purpose (wild-sourced individuals are sometimes from areas undergoing a significant land-use change, though). The Australian tree fern also has low survival rates in areas that have been substantially disturbed, and the absence of this species in clear-felled areas has its toll. Dicksonia antarctica is considered a keystone species in wet forests. It provides habitat for other plants such as epiphytic ferns and mosses as well as critical habitat for the endangered Narracan burrowing crayfish (Engaeus phyllocercus, PDF), which live beneath the root mats.