Davidson’s plum (Davidsonia jerseyana), also known as Mullumbimby Plum, is an endangered fruit species indigenous to Australia. The fruit grows on a small, slender tree that grows 6-10 meters tall with long leaves between 35-75 cm in length. Flowers are small and dark pink or red. Two specimens exist: those growing closer to the ocean (of which fewer than 100 wild trees are estimated to exist) produces flowers and larger fruits on short stems closer to the trunk of the tree; while the other type produces flowers and fruits in loose bunches branching off from a main stem. The fruit is dark purple in color, oval-shaped and covered with fine hairs. Each fruit contains two large seed cases with a single seed. Its flesh is fibrous and dark red when fully ripe. The taste is sour with some astringency and slight bitterness. The trees fruit between November and February, and typically start producing large crops by their fourth year. This species of Davidson’s plum has been a staple in the diet of the Aborigines, Australia’s indigenous people, for tens of thousands of years, and was traditionally used for medicinal purposes. Aborigines ate the plums raw, and used the tree trunks to make harpoons for catching turtles and hunting dugong (a marine mammal). Distribution occurs in a narrow belt of northeastern coastal New South Wales and immediate inland areas, including around the city of Mullumbimby, from which it gets one of its common names. Today, about 6-7 tons of Davidson’s plum are harvested annually, and used to produce jams, fruit wine, ice creams and sauces. The plums and their by-products can be found for sale commercially. In the wild, habitat alteration and fragmentation – through the clearing of large areas of natural habitat for agricultural activities and urban development – has destroyed or isolated many Davidson’s plum populations. Many trees are remnants, left growing in isolation in land converted to pasture, where a combination of dense pasture grass, grazing and trampling inhibit or prevent regeneration from these isolated trees, and open-sites provide unfavorable conditions for seedling development. Cattle often destroy flowers on the lower section of the trees. These isolated trees have little chance of reproduction, pollination or seed dispersal, and so gene flow between many tree populations may have ceased. Exotic weed invasion also threatens this native species, particularly Camphor Laurel and Lantana, which is capable of smothering both juvenile and adult plants. Current growers are experimenting with growing trees under netting with equal height pruning to assist in eliminating fruit loss due to bird predation, sun damage or fruit fly strike.
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