New Forest Service field guide identifies increasing numbers of invasive plants & trees in the South

New Forest Service field guide identifies increasing numbers of invasive plants & trees in the South

New Bern, NC – INTRO - A recent publication by the Forest Service Southern Research Station highlights the continuing and growing problem of invasive non-native plant and tree species in Southern forests. George Olsen has more.

The "Field Guide for the Identification of Invasive Plants in Southern Forests" updates the original 2003 publication of which 160,000 copies were distributed. An update was needed in seven years time the book adds 23 new invasive species.

"The degree of invasion has continued to worsen. We're up to about 9% of forests in the region that have at least one invasive usually more than one that occupy them."

Jim Miller is a research ecologist with the U-S Forest Service Southern Research Station and is based at Auburn University. He's the lead author of the field guide's update. He's on high alert for one particular invasive not currently found in North Carolina but in states surrounding us which could threaten some of our rare plants as well as the state tree.

"We have efforts in 7 states right now to combat cogongrass because it will replace not only the longleaf pine but the ecosystems that are a unique high species richness also threatens endangered species like the gopher tortoise and the indigo snake that cohabitates with that. But then that's also, the whole system along the coast with your pitcher plant bogs and your swells and your Carolina bays, that will all be, if not eventually stopped, overrun by cogangrass."

There's plenty to worry about without thinking about what may come. Miller notes two invasive species of trees attacking from the west and east that could threaten the native ecology. From the west it's the Tree of Heaven

" a misnomer I guess, it could be the tree of something else "

The Tree of Heaven has been in the United States since the 1700s coming over from China but has only recently been seen in North Carolina. It's a concern as Miller describes it as "a complete stand replacement monoculture forming species."

"The tree of heaven is one that forms dense stands that would replace hardwood forests with this low value tree, so it comes on, grows rapidly. Tree of Heaven can grow 12 feet in two years so its something we don't have naturally out there that will replace not only the tree species but the understory."

Attacking from the east is the Tallow tree. It's introduction to the South came in the 1700s when Ben Franklin sent tallow trees to South Carolina for use in a soap industry that never came to fruition. It also is a recent introduction to North Carolina.

"The tallow tree is particularly insidious as it takes over coastal prairies and coastal dune systems and those highly rich, species rich coastal habitats, and then they'll just form the forest where perhaps there wasn't a forest. It takes out the hardwood trees, all those ones along there."

There may be immediate hope in keeping the tallow tree from taking firm root in North Carolina. Miller says a new herbicide found 3 years ago to combat a reedy grass that was taking over marshes also appears to control tallow without harming hardwood trees. But, whether or not a method of eradication is found, keeping invasives like the Tree of Heaven or Tallow trees from infesting North Carolina forest stands may be a never ending battle unless information such as that found in the new field guide becomes common knowledge.

"Tallow tree just got a toehold in N-C, very small acres in the forest. But the trouble is both of them are planted as ornamentals and so they'll crop up wherever we have cities and humans who are unaware of their dire threat to our forest and natural lands."

Jim Miller is the lead author of the Field Guide for the Identification of Invasive Plants in Southern Forests published by the U-S Forest Service Southern Research Station. I'm George Olsen.

People can request copies of "Invasive Plants in Southern Forests" by sending their name and complete mailing address, along with book title, author, and publication number
GTR-SRS-119 to:

"Invasive Plants in Southern Forests" is posted in PDF format on the SRS website at In addition, the book is available in html format at