Overview
Objectives
Compare how early treatments of prescribed fire and mowing in planted longleaf pine (Pinus palustris) plantations differently affect pine growth.
Provide landowners with a better understanding of how silvicultural actions affect longleaf pine establishment and growth.
Summary / Lessons Learned / Additional Thoughts
As of the 2024 tree measurements (Age 6), the study showed that prescribed fire reduced longleaf pine growth by 9.6% while mowing had no negative or beneficial effect on growth (nonsignificant 3.6% reduction). There is no indication that survival was affected by either treatment. Understory measurements will be reported soon.
Long Description of Practice
The whole stand was planted to longleaf pine in January of 2018 using Florida containerized longleaf pine (Andrews Nursery Chiefland). The previous stand was a mature loblolly pine stand clearcut in 2015. Site preparation was raking and piling of debris. Prescribed fire was first applied in May-June 2022. Herbicide and mowing was conducted in October of 2022. Mowing and herbicide occurred between rows only. The herbicide treatment was dropped from the tree growth analysis because of negative effects on longleaf pine (see below).
Results
Tree Diameters Table
| Date (month / year) | Species | Control (inches) | Fire (inches) | Mow (inches) |
|---|---|---|---|---|
| 1/2025 | Longleaf pine | 8.3 | 7.5 | 8.0 |
Study Location / Installation Information
Lattitude
Longitude
Accessibility
Landowner HAS consented to property visits WITH PERMISSION
Who installed study
First name: Timothy
Last name: Martin
Year of installation
2018
Does study have end date
NO
Planned or actual end date
Information not provided.
Contact for access
Is study monumented
YES
Photos
Stand Information Pretreatment
Land Use History
The Austin Cary Learning Forest was in pine forest and/or silvopasture systems since the late 19th century. Prior to this, it is unclear if agriculture was present on the property. There has been a mix of naturally regenerated slash and longleaf pine in the stand prior to the most recent (~1980s-2018) loblolly pine plantation. Silviculture (fertilization, herbicide application) was likely minimal on the prior loblolly pine plantation.
Stand Area
5 Acres
Stand Age Before Treatment
Information not provided.
Pretreatment Overstory Community Composition
Loblolly pine plantation
Pretreatment Forest Metrics
Total Basal Area
Information not provided.
Species Composition
Information not provided.
Soil Series
Tavares sand (85%). The Tavares series consists of very deep, moderately well drained soils that formed in sandy marine or eolian deposits. Tavares soils are on hills, ridges and knolls of the lower Coastal Plain. Slopes range from 0 to 8 percent. Mean annual temperature is about 22 degrees C (72 degrees F), and the mean annual precipitation is about 1397 millimeters (55 inches).
Apopka (6%).The Apopka series consists of very deep, well drained, moderately slowly permeable soils on upland ridges, side slopes and knolls of the North Central Florida Ridge (MLRA 138), the South-Central Florida Ridge MLRA 154) and the Florida Flatwoods (MLRA 155). They formed in thick beds of sandy and loamy marine or eolian deposits. Near the type location, the mean annual temperature is about 73 degrees F., and the mean annual precipitation is about 52 inches. Slopes range from 0 to 25 percent.
Silvicultural Application(s) Used in Study
What did the study investigate?
- Mowing
- Prescribed Fire
If silviculture included a harvest, what type(s)?
Information not provided.
Silvicultural Action(s) Timings and Types / Intensities
Date |
Silvicultural Action |
Study Focus? |
| 16/06/2022 | Prescribed fire | Yes |
| Mowing | Yes |
Are there any local forest health threats to your target species?
No
Notes on silvicultural process(es) or data collection?
The study included a broadcast spray herbicide treatment in 2022 but the longleaf pine showed damage from the treatment (12 oz Polaris AC (imazapyr) product / ac applied) and so results from this treatment are not included. Unclear if application rates were too high for these sandy soils as longleaf pine can tolerate herbicide application.
Plans for Future Treatments
Prescribed fire and mowing will be applied again 2025.
Plans for Future Measurements
Biennial measurements of tree characteristics will continue. Understory biomass and diversity are being monitored. Branch senescence measurements are planned.
Costs and Economic Considerations
These were not documented for the study. Typically, mowing is more expensive than prescribed fire in the region.
Scientific Study Information
Is this study published?
No
Study Design
Randomized complete block design.
Number of Replicates
4
Size of Plots
4 Acres
Planting Density
660 Plants per Acre