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Experiment Tries to Curb Melaleuca Threat to Everglades

May 3, 1988

MIAMI (AP) _ The Everglades will disappear if the melaleuca tree is not curbed, but an experimental herbicide program could help stop the spread of the thirsty Australian import, experts said Tuesday.

Aerial spraying began last week in the Loxahatchee National Wildlife Refuge in Palm Beach County, but will take up to 10 months to evaluate, said the park’s chief biologist, Mark Maffei.

The melaleuca was imported in 1906 to sow in the Everglades, which was then seen as just ″a mucky wasteland,″ said biologist Julia Morton of the University of Miami. Those bringing in the tree hoped it would turn the land into a productive timbering area.

The idea worked only too well, and by the time scientists and the public realized the enormous environmental value of the Everglades, the melaleuca was beginning to wipe parts of the habitat out.

The thirsty Australian tree soaks up water rapidly, and thrives in fertilizer-enriched waters that now flow into the Everglades. The proliferation of melaleuca crowds out the native plants, which evolved in an era when the water had few nutrients.

″It’s now invaded a half-million acres, and 40,000 acres are solid melaleuca,″ Ms. Morton said. She refers to the tall, thin trees with papery bark as ″weed trees.″

If the tree is not stopped, the Everglades will eventually disappear under a forest of melaleuca, biologists fear. The tree is hard to control because it grows rapidly and because it has an unusual defense mechanism: It sends out a load of airborne seeds at the first sign of heat from a fire or even the chop of an ax.

Maffei said the melaleuca and the deteriorating water quality are the Everglades’ two biggest environmental problems.

Since 1985, Loxahatchee and other Everglades-area parks have been using ″hack and squirt″ methods to control the tree, said Maffei.

That labor-intensive process involves hacking each tree and injecting an herbicide. Trees are also uprooted and seedlings are pulled and burned.

The method has eliminated about 50,000 melaleuca, but Maffei estimates hundreds of thousands remain in his park alone.

Last week’s spraying test could be a first step in finding a cheaper, faster method of controlling the melaleuca. Utility companies have been using the spray to control growth along their transmission lines with good results, Maffei said.

But a refuge is not a utility company, and the effects of the aerial spraying must be carefully evaluated, he said.

″We have to worry about the other plants, the wildlife and the period of time the chemical stays in the habitat,″ Maffei said.

Something must be done, however, he said.

″If we don’t stop the melaleuca, we are going to lose all the native habitat anyway,″ said the biologist.

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