Three year burn frequency effects in a piney flatwoods ecosystem

Objectives

The objective of this demonstration area is to contrast the effects of fire frequency on understory species composition in a mixed longleaf (Pinus palustris) and slash pine (Pinus elliottii) flatwoods forest. Two adjacent stands feature one- and two-year burn frequencies and offer a visual contrast with this three-year burn area.

Summary

A three year burn interval leads to an understory dominated by gallberry (Ilex glabra), saw palmetto (Serona repens), and other woody shrubs. Likely because of the shrubby understory, there is very little pine regeneration. In contrast, the understory of the one-year burn interval is predominately grasses (i.e., wiregrass (Aristida stricta)), and the two year intervals has a mix of grasses and shrubs. The one-year burn has no pine regeneration, while the two-year burn intervals has pockets of pine regeneration.

Long Description of Practice

Information not provided.

Date (month / year)Species / Type

Study Location / Installation Information

Lattitude

29.737803

Longitude

-82.218794

Accessibility

Landowner HAS consented to property visits WITH PERMISSION

Who installed study

First name: Scott

Last name: Sager

 

Year of installation

1998

Does study have end date

NO

Planned or actual end date

Information not provided.

Contact for access

Is study monumented

YES

Stand Information Pretreatment

Land Use History

Prior to 1936, the area was cut for timber, residual trees were worked for turpentine, and cattle grazed the area. The state acquired the site in 1936, after which the forest naturally regenerated from the residual trees, mostly longleaf pine. The stand was intermittently burned and minimally harvested for several decades, but a more concerted effort was made in 1998 to consistently burn at the three year interval. In 2016, a preparatory harvest was completed to reduce basal area to approximately ~75 ft2/ac from the previous 90 ft2/ac. In 2023, another harvest was performed to reduce basal area to 55 ft2/ac. The 2023 harvest initiated the single-tree and group tree selection experiments (also described in the library). The School of Forest, Fisheries and Geomatics Sciences, University of Florida, manages ACF as a research, education, extension, and demonstration forest.

Stand Area

104 Acres

Stand Age Before Treatment

95 Years Old

Pretreatment Overstory Community Composition

Longleaf pine and slash pine

Pretreatment Forest Metrics

Total Basal Area

78 Feet Squared per Acre

Species Composition

Information not provided.

Soil Series

Ultic Alaquods (Pomona series), deep and poorly drained; sandy texture with a spodic horizon extending from 9.8 to 35 inches (25 to 89 cm), and an argillic horizon with low permeability from 35 to 80 inches (90 to 203 cm).

Silvicultural Application(s) Used in Study

What did the study investigate?

  • Prescribed Fire

If silviculture included a harvest, what type(s)?

Information not provided.

Silvicultural Action(s) Timings and Types / Intensities

Information not provided.

Are there any local forest health threats to your target species?

No

Notes on silvicultural process(es) or data collection

Slash and longleaf pine were harvested proportionally to their basal area distribution in the stand, meaning there was no bias towards harvesting either species more than the other. After harvesting, tops were spread throughout the forest. Several landings are found in the stand. An extensive network of fire breaks are maintained in the forest.

The stand has had near continuous measurements of weather, water, and carbon cycling since 1999 using a technique call 'eddy-covariance'. You can read about this method and results for the site at https://doi.org/10.1016/j.foreco.2023.121408

Plans for Future Treatments

The site will continue to receive prescribed fire on three-year intervals as a contrast for the nearby one- and two-year burn interval areas.

Additional selection harvests will likely occur between 2045-2055 depending on pine infilling and growth rates.

Plans for Future Measurements

The eddy-covariance tower will continue to measure forest carbon and water cycling.

Tree growth and understory characteristics will continue to be measured at periodic intervals by Jason Vogel and Timothy Martin. See the descriptions of the single tree and group selectin experiments in the forest.

Costs and Economic Considerations

Information not provided.