The Mareeba Dimbulah Irrigation Area project looked at ways of developing the knowledge base on the production of tea-tree oil for an internationally competitive and sustainable industry.

Dr James Drinnan details findings from the project in his report Development of the North Queensland Tea Tree Industry recently published for the Rural Industries Research and Development Corporation.

"The project has shown the potential of tea-tree oil production in other areas of Australia and there is likely to be substantial further expansion of the industry as production and marketing issues are further resolved, he said"

The project developed guidelines for scheduling irrigation to maximise oil yield and quality and it establish a gene pool of superior plants, helping growers to change their farming practices and increase yields.

"Tea-tree oil production is a relatively new industry on the Atherton Tablelands. Previously the industry was located almost exclusively in Northern NSW," Dr Drinnan said.

"Interest in tea-tree oil production was generated as an alternative crop for tobacco in the Mareeeba Dimbulah Irrigation Area which was undergoing structural change due to large reductions in tobacco quotas," he said.

He says the results of the research work have important implications for the way in which tea trees are managed for maximum production.

"In order to achieve high yields it is essential superior seed lines are used by selecting seed from known good parents," he said.

 "Then the trees must be intensively managed with regular irrigation and fertiliser. Finally trees should be harvested either just before the wet season in December or just after the wet season in April.

"Growers in the Mareeba Dimbulah area have been able to use this information to change their farming practices and increase yields."

But Dr Drinnan says more research is needed on fertiliser requirements to maximise growth rates and on weed and pest control.

 "For long-term international competitiveness the development of efficient growing and production techniques are vital," he said.

Dr Drinnan says the tea-tree oil industry began as a cottage industry in Northern NSW where tea trees were harvested from natural stands.

"With the mechanisation and intensification of the industry there has been a need to develop management guidelines to maximise yields and minimise the costs of production.

"Recently the plantation industry has expanded from being located almost entirely in Northern NSW to other areas of Australia with the potential for higher production, like the Atherton Tablelands.

"In these areas tea trees are being grown in different climates and on different soil types.  Little was known about the levels of production or how to manage the trees.

"Growers had used information from NSW to help establish plantations, however there was a real need for research work to adapt and alter this information and determine the factors which affect oil concentration and yields in these areas.

"In North Queensland all plantations are irrigated and, in the absence of better information, growers had mostly adopted an irrigation regime similar to that used in tobacco."

The report Development of the North Queensland Tea Tree Industry is available from RIRDC for $10, plus $4 postage and handling. Phone 02 6272 4819 to order.

Contacts: Dr James Drinnan, phone (070) 928 555, fax (070) 923 593
               RIRDC Communications, phone (02) 6272 3186