Evaluation - Demonstration Sites


The Clewiston site is a swath of land in southern Hendry County just southeast of the city of Clewiston along Highway 27. The land is owned by U.S. Sugar Corporation.  The TAME Melaleuca demonstration site comprises 33.6 acres dominated by melaleuca with scattered mature dahoon holly trees, wax myrtle, ferns, and saw grass.

Consistent with most reclaimed wetlands in the area, the soil at the site is primarily muck.

No detailed soil data are available for the Clewiston site.  Historically, the site is seasonally flooded with 3-6 months of standing water in the summer.

When averaging across the entire site, melaleuca occurs at a density of approximately 3,741 trees per acre. Tree sizes, when measured at breast height (dbh = 1.3 m), range from 0.2 to 52.9 cm, with an average diameter of 6.8 cm. Although melaleuca dominates the demonstration area, there are 55 other plant species occurring at the site (see Table 1).

Nearly a third of the plant species occurring within the demonstration site are exotic including Schinus terebinthifolius, Bidens pilosa, Casuarina equisetifolia, and Lygodium microphyllum. However, there is a large proportion of native tree and shrub species as well as understory species at the site, which might facilitate re-vegetation efforts after removing the exotic plants.

Table 1. Plant species occurring at the Clewiston demonstration site.

Unknown Fern --
2 Unknown Vines --
3 Unknown Shrubs --
Unknown Milfoil-like plant --
Acrostichum danaeifolium Giant leather fern
Baccharis glomerulifolia Saltbush
Blechnum serrulatam Swamp fern; toothed midsorous fern
Casuarina equisetifolia* Australian pine
Cupaniopsis anacardioides* Carrotwood
Eupatorium sp. --
Hydrocotyle sp. Pennywort
Lemna valdiviana Duckweed
Lygodium microphyllum* Old-world climbing fern
Melaleuca quinquenervia* Australian paperbark tree
Micranthemum sp. Mudflower
Mikania scandens Hemp weed
Nephrolepis cordifolia* Narrow swordfern
Peltandra virginica Arrow arum
Phragmites australis Common reed
Pontederia cordata Pickerelweed
Psilotum nudum Whisk fern
Rhynchospora colorata Star-rush
Rhynchospora inundata Beak sedge
Senna pendula* Climbing cassia
Schinus terebinthifolius* Brazilian peppertree
Unknown 7
Exotic 7
Native 14
Total 28

Three conventional melaleuca control approaches are featured at the Clewiston site:

  • felling trees and treating the stumps
  • hack and squirt
  • aerial applications of herbicides

The use of biological control is also emphasized, along with its integration of this approach with each of the other conventional control approaches. In addition, a smaller demonstration is available on the effectiveness of "off the shelf" herbicides that homeowners can purchase from local hardware and garden stores. You can find a detailed description of these approaches on the Clewiston Demonstration Site page.

We monitor the efficacy of these control approaches by delineating multiple study plots in each treatment and measuring over time the melaleuca mortality, recruitment, and changes in plant species composition. With these measures of efficacy, coupled with the cost of each treatment, we compare the different approaches as to their suitability for large land owners and vegetation control specialists.