The contribution of horticulture to the conservation of critically endangered Wollemia nobilis

After the critically endangered conifer Wollemia nobilis (Wollemi pine) was discovered in late 1994, an urgent task was to determine its cultivation requirements so that an ex situ population could be established. Propagation from extremely limited material was the first challenge, followed by development of a genetically representative ex situ conservation population. While the ex situ population was developed for insurance against loss of diversity in the wild population, it has also been used for research, and as the source of material for translocations, dispersed garden plantings and a botanic garden metacollection. Here, we report how these challenges were approached, based on nascent understanding of W. nobilis – as an Araucarian and as a rainforest emergent. As studies into the morphology and biology of the species progressed, these findings were used to refine propagation techniques. The establishment of this species in gardens around the world has expanded our knowledge of its biology and ecology. Insights concerning its behaviour in cultivation include its intolerance of extreme heat, extreme cold, high light and drought, and a preference for free-draining and acid soils – conditions approximating to its temperate rainforest origin. Now that these garden plants have begun to produce seeds, there is the opportunity for deeper research into factors influencing seed viability and plant establishment from seeds. This paper reviews many of the published studies aimed at understanding various aspects of W. nobilis biology, particularly those relevant to informing its requirements in cultivation. We also present data and conclusions drawn from unpublished studies which cumulatively aid efforts to conserve the species ex situ.