Pinus radiata invasion in New South Wales: the extent of spread

Moira C. Williams and Glenda M. WardleA, Institute of Wildlife Research, School of Biological Sciences, Heydon-Laurence Building A08, The University of Sydney, Sydney, New South Wales 2006, Australia.
A Corresponding author.


Recognition of invasive species in the early stages of invasion is a major priority for weed research and yet too often invaders only receive adequate attention when they are already widespread and control is costly. Many species of the Pinus genus are successful invaders imposing harmful ecological impacts across the southern hemisphere. In Australia, the potential for pine invasion is high because more than one million hectares of commercial pine plantations are cultivated, which often border native vegetation. To date, quantitative assessments of the extent of invasion have been limited to small geographic areas. We surveyed the vegetation surrounding all the major Pinus radiata plantations in NSW in order to determine the current extent of invasion and to help prioritize the species as an invader. Nine out of 29 sites bordering plantations were heavily invaded; suggesting that on a landscape scale the species is yet to have a large impact. However, at the most infested sites pine basal areas reached more than 50 m2 ha-1 and pines were found up to 10 km from the source plantation. The World Heritage Blue Mountains region has experienced some of the highest levels of invasion, thereby demanding adequate control measures to protect areas of high conservation value. Given the large potential for spread and known impacts of invasive pines elsewhere, effective control in the early stages of invasion and the implementation of measures to prevent further spread of the species are paramount.

Keywords: eucalypt woodland, weed, mapping, impact.


Plant Protection Quarterly (2009) 24 (4) 146-156.