Scientists are working against the clock to collect genetic information from one of the last remaining natural stands of radiata pine on the island of Guadalupe off the west coast of Mexico.
The genetic heritage of this species, one of the world’s most widely grown trees, is under threat from fungal infection and ravenous goats.
“Australia’s radiata plantations are much less diverse than the native populations although they occupy a much greater area,” says Dr Colin Matheson of CSIRO Forestry and Forest Products, who joined researchers from American and Mexican universities on an expedition to Guadalupe Island in May 2001.
“CSIRO does a lot of breeding work with industry and we need to access as much genetic material as possible to continue a program of tree improvement,” he says.
Dr Matheson continues, “In particular, we are interested in the Guadalupe Island trees as they grow in a dry climate and have higher density wood. We are investigating planting radiata in drier parts of the Murray Darling Basin beyond the range currently thought of as economically viable”.
With a world wide plantation area totalling around 4 million hectares radiata pine is a very versatile species and is used widely in Australia for building and construction, for paper making, in composite wood products and in hygiene products.
Natural stands of radiata pine are now very limited with three on the Californian coast and two on islands off the Pacific coast of Mexico.
The Californian stands are infected with a fungal disease called pitch canker which is carried inside the actual pine seed. This means seeds from these stands cannot be imported into Australia until a treatment that can eliminate the fungus without killing the seed is developed. Previous collections, made before the disease appeared, have sampled these mainland populations.
The stand of just 220 trees on the rugged Mexican island of Guadalupe is currently in good health but is under threat from the voracious appetites of the island’s goat population, which make a quick meal of any young seedlings.
“While the existing trees mostly look healthy, the stand’s survival prospects are uncertain. Its long-term future may depend on the success of current efforts to capture all the island’s goats and ship them to the mainland,” says Dr Matheson.
Each seed sample collected by Matheson and his colleagues has been carefully recorded noting the tree that it came from and the exact the location of the tree.
“We hope that, after quarantine requirements have been met, this seed can be brought into Australia and tested in low-rainfall areas”.
“The task of collecting these valuable seeds was physically extremely challenging,” says Dr Matheson. “The trees grow at altitudes of up to 1200 metres along the rim of a volcano and reaching them required a steep and rough 300 metre climb from our camp site. We then had to walk about 6-7 km to the furthest trees down a sloping, rocky ridge to an altitude of 500m. The worst bit was carrying the pine cones back to camp!”
The expedition was partly sponsored by the Department of Industry, Science and Resources.
Materials provided by CSIRO Australia. Note: Content may be edited for style and length.
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