Alternative Name(s): Monterey pine, Insignis pine after an earlier botanical name Family: Pinaceae Form: Tree Origin: Native to small areas in coastal California Weed Type(s): Naturalised, Environmental Weed

Photo: T. Rudman, DPIWE Tas

Notes: Radiata pine is a tall evergreen conifer growing up to 50m tall in high quality plantation areas. The form of the tree in closely-spaced plantations is narrow while open-grown trees become spreading. Radiata pine bears separate male and female flowers on the same tree with the female flowers developing into woody cones with large numbers of winged seeds. Viable seed may remain in the cones for several years and are often shed abundantly after fire which kills the parent tree.

In the rush to reduce dependence on imports of softwood timber many thousands of hectares of unalienated native bushland were cleared and planted with Radiata pine. The extent of the plantation was often determined by adjacent land ownership and steepness of terrain . This meant that plantations often have a common border with conservation reserves and other native bushland. By 2003 there were over 716,500 ha of Radiata pine in Australia.

A target of 16,000 ha was set for the ACT and this had almost been reached when major bushfires in 2001 and 2003 destroyed over 11,000 ha. A decision has been made to replant up to 7000 ha with Pinus radiata together with areas of native vegetation. The problem of weediness will reappear when the plantations reach seeding age.

Pines have winged seeds which has aid their dispersal into bushland where they compete with native species. In practical terms it may never be possible to eliminate this dispersal while the seed source remains. Genetic modification to produce sterile pines which put more energy into wood production than reproduction appears to be the only solution to invading pines however this scientific achievement is a long way off.

References:

Randall, R. P. (2002). A Global Compendium of Weeds. R. G. & F.J. Richardson, Melbourne.