"Eventually, if nothing was done to stop it, the tree would take over the park," said Anna Sheppard, part of a team of people working to eliminate the plants.
Although Campbell said he believes the invasive plants might have been in the park since it was created, he said no native species have been lost. The park still has an opportunity to stay ahead of the damaging plants if it acts now, Campbell said.
In the case of Tree-of-Heaven, it's not a matter of cutting it down.
Park officials said if the trees are cut, they will sprout faster.
Tree-of-Heaven trees are being treated with herbicide, which is the most effective way to control the problem, park spokeswoman Marsha B. Wassel said in a news release.
More than 500 acres in the park have been surveyed for invasive plants and almost 100 acres have been treated, Wassel said.
Campbell said the entire park will be surveyed for invasive plants.
Six interns with the Student Conservation Association are working with park officials to control the invasive plants, Wassel said. The Student Conservation Association, the nation's leading conservation service for young people, each year provides 1.5 million hours of service to parks, forests and similar areas, Wassel said.
The team has been working on the problem since October and expects to stay on the job until February, Wassel said.
The team also is trying to alert local residents to the problem of invasive plants with the hope that property owners will do their part to control the plants on their own land, Wassel said.
"Our team can work in the park, but if our neighbors don't help out, they will just come back," said Rachael Carter, one of the interns working on the project.
If local landowners are not sure how to identify invasive plants, they can ask for help through a local agriculture extension service or get information about the plants through Web sites, Campbell said Tuesday.