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Invasive Species Pose Challenges

TBO.com photo by KEVIN BRADY

Aiming to rid E.G. Simmons Park of invasive Australian pines, Ryan Oliver, a worker with Delta Seven Inc., an environmental consulting company, sprays a herbicide on the stump of one of the trees. Oliver sprayed 84 large Australian pine stumps and numerous smaller saplings and spouts during the treatment. “Typically, once we apply the herbicide to the stumps that’s it for them,” Oliver said. “They will be good and dead.”

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By SUSAN M. GREEN

The Tampa Tribune

Published: July 11, 2008

Updated:

RUSKIN - At E.G. Simmons Park, contract workers scale towering Australian pines and lop off limbs before felling the trees and feeding them to an industrial-sized wood chipper.

In less than an hour, the big machine can grind up a tree 40 to 50 feet tall and spit it out in millions of pieces to be hauled away for mulch.

But that's not the end of it. The Australian pine packs a mighty sucker punch.

"You always have literally hundreds of them," said environmental scientist Jennifer Roberts, pointing to the little suckers left behind, the new plants that were feeding off the mama tree's roots. The suckers are among reasons the invasive exotic tree is considered tough to eradicate from preservation areas.

The park's staff will come along and kill the suckers once the parent trees are gone, Roberts said.

But it's too dangerous for untrained workers to cut down the full-grown trees, Roberts said, so the job was hired out, courtesy of an $80,000 grant from the county's Pollution Recovery Fund. The grant must be matched by $25,500 worth of in-kind services such as equipment and labor.

The Pollution Recovery Fund, overseen by Hillsborough's Environmental Protection Commission, is fueled by penalties assessed polluters or others cited for environmental violations.

The county's Parks, Recreation and Conservation Department, which manages preservation lands as well as recreational parks, depends on such funding to help pay for maintenance items like nuisance plant removal.

In 2004, the department received a $43,000 grant to remove Australian pines at Simmons. In 2005, a $60,000 grant paid to remove Brazilian pepper trees.

Left alone, invasive plants crowd out native species that support wildlife and make up a healthy Florida environment, scientists say.

Not only that, but birds and sea breezes carry seeds that spread the pesky plants to other areas and perpetuate the problem.

Like prescribed burns that depend on appropriate weather conditions, eradication of nuisance plants by power saw or herbicide requires timing. For example, at Simmons, the staff waited until early summer, when the brutal sun slows the number of campers, to tackle the Australian pines, Roberts said.

The staff plans to replace many of the unwanted trees with 15-foot-tall oaks that, over time, will grow to provide shade for visitors without casting a pall on the native habitat.

Without a dedicated funding source for maintenance of environmentally sensitive lands, the parks staff tries to stretch grants as far as possible, Roberts said.

For example, the bids for removing 84 Australian pines came in $30,000 lower than anticipated based on estimates from a year or so ago. Roberts said tree service representatives attributed the difference to a slowdown in the construction industry.

She said the parks department will try to get the award specifications changed to target other nuisance plants at Simmons.

Tom Ash, who oversees the grant program for EPC, said the request to target additional nuisance plants must go to the agency's Citizens Environmental Advisory Committee and then the EPC board for consideration, probably this fall.

Reporter Susan M. Green can be reached at (813) 865-1566 or sgreen@tampatrib.com.

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