Bunya pine grows in "two broad geographic regions: a large area in the south-east of the State and two smaller areas in the far north. In both regions it is found in rainforest, often growing in association with hoop pine (Araucaria cunninghamii). In South-East Queensland there are five main areas where the bunya pine occurs naturally within the range 26.25 °S to 27.00 °S: in the Blackall Ranges to the west of Nambour, in the upper Mary River Valley, in the ranges in the upper reaches of the Brisbane River, in the Yarraman-Blackbutt area and on the Bunya Mountains to the west of Yarraman. In North Queensland the two small stands are on Mt.Lewis (16.50 °S) and at Cunnabullen Falls (17.67 °S). Bunya pine occurs naturally on soils that are basaltic in origin and in areas with an annual rainfall greater than 1000 mm. The species is able to tolerate temperatures ranging from -4°C to 40°C" (Huth 2002).
"Moist conditions are required for successful germination. Germination has been recorded in humid conditions within the decomposing cones" (Huth 2002). The germination is hypogeal, meaning that the seed first produces a root and then translocates the seed's nutrients to a tuber, from which the shoot then emerges (Burrows and Stockey 1994). I believe this mechanism is unique, at least among conifers, to the bunya. A study by Smith and Butler (2002) found that shoot emergence for seeds planted in a moist, shaded site can take a long time: 2-(7-11)-24 months after sowing. These delays may facilitate seedling by ensuring that some seedlings are available to take advantage of growth opportunities at any time during the approximately 3 year interval between masts. That mast interval, by the way, may be correlated with the ENSO or some other climate cycle (Smith and Butler 2002).
"At maturity ... the intact female cone with scales still green on the surface falls from the tree. As the cone is very heavy, and as the seeds usually remain in the cone until after it falls from the tree, seed dispersal is limited to the area covered by the cone rolling on slopes, or being transported by water flowing in creeks or gullies" (Huth 2002). The absence of effective dispersal is one likely explanation for the very restricted range of this species. The peculiar dispersal mechanism would seem to imply that, as with Pinus albicaulis of North America, there should be some sort of animal vector (perhaps now extinct) to transport the bunya nuts. Smith et al. (2007) investigated this problem by tagging seeds and placing them on the ground with naturally fallen seeds, during a mast year. Some seeds were eaten by animals, but some were carried up to 8 m from the tree, sometimes in an uphill direction. Later, seeds were placed and monitored with a video camera, which recorded seed collection and dispersal by the short-eared possum Trichosurus caninus. This is the first evidence of an animal vector, other than humans, that can disperse A. bidwillii seed. It is worth considering, though, that the large, nutritious bunya seed is well adapted to survival within the forest environment. It germinates best in moist conditions, and the generous food supply in the seed facilitates hypogeal germination, which may confer a competitive advantage to a seedling forced to compete with other seedlings trying to colonize a forest edge or gap environment. Thus the large bunya seed may function not to lure animal dispersers, but to produce a competitive seedling.