Home » Research Projects

Fuel Reduction Options for Landowners at the Wildland-Urban Interface

Introduction
The wildland-urban interface (WUI) can be defined as the area where homes and entire communities are built within or adjacent to wildfire-prone areas. A major issue in the southern WUI is the loss of homes and other structures to wildland fire. Fire is an important and necessary ecological process in many natural areas of the southern United States. One ecological function of fire is the reduction of grasses, shrubs, vines and small branches that are the main vegetative fuels for fires. Both living and dead plant materials burn, and in many southern forests, substantial amounts of such vegetation accumulate every five to six years. Periodic wildfires historically burned through many Southern natural areas more frequently than that and effectively reduced the vegetation accumulation.

As more homes are constructed within the WUI, the periodic fires that reduced fuel accumulations are being suppressed to reduce risk to structures and to reduce hazard and liability issues associated with smoke. Ironically, this suppression allows vegetation to grow unchecked and create dense vegetation that is capable of supporting intense fires, in turn increasing the risk of structural damage by wildfires. No fire control agency or local government has the resources to reduce high accumulations of vegetation in natural areas surrounding every home in the WUI; therefore, in most situations individual landowners must assume some responsibility for reducing this risk.

Fuel reduction around structures will greatly reduce the risk of damage caused by wildfire and several options exist for reducing fuel buildups in natural areas. Prescribed fire, which mimics historic natural fires, is one option; however, in many situations its use is not acceptable to neighbors and local governments in the WUI due to the potential of the fire escaping or of smoke causing hazardous conditions for nearby airports, hospitals, homes, and roads. Alternative methods for fuel reduction include herbicides, mechanical thinning, mowing and chopping, or livestock grazing, which may or may not be more acceptable to nearby homeowners.

The University of Florida (UF), in partnership with the Center, conducted a review of fuel reduction options available to small landowners; the findings of the detailed report are summarized below. In addition, UF initiated a research study to compare the effectiveness, longevity and costs of three fuel reduction treatments in the South. This study is summarized below as well.

Fuel Reduction Options Technical Report
The primary goal of the report was to investigate fuel management techniques that are suitable for small landowners living in the wildland-urban interface. Prescribed fire, herbicide treatments, mechanical treatments, and the utilization of livestock for fuel reduction were each reviewed based on the available literature for their effectiveness and associated costs. A summary of each technique follows:

Prescribed fire
  • Reduces live and dead fuels effectively for one to several years. However, many problematic species resprout following fire.
  • It is necessary to repeat every 2 to 4 years for long-term effectiveness.
  • Prescribed burning permits are required.
  • Cost for contractor to conduct prescribed fire: $15-$50 per acre.
  • Cost for State to conduct prescribed fire: $10-$20 per acre.

Herbicide treatment

  • A single treatment provides long-term live fuel reduction, but the effect on total vegetative fuels is not immediate since the dead plants remain until they decay.
  • Follow herbicide with burning or chopping to reduce dead vegetative fuels sooner after herbicide treatment.
  • Some local restrictions and licensing may be required for applications of certain herbicides. Check with your county extension agent.
  • Cost to purchase herbicide application equipment: $30-$150 (not including cost of herbicide).
  • Cost to purchase herbicide: $55-$450 per gallon.
  • Cost for contractor to apply herbicides: $70-$150 per acre (includes herbicide).

Thinning trees

  • Reduces live fuels effectively, but can increase downed trees or limbs unless they are harvested or burned.
  • Thinning treatments remain effective for one to several years. However, problematic understory species may become established following cutting.
  • Couple thinning with prescribed fire or herbicide for long-term effectiveness.
  • Cost for contractor to thin: $100-$170 per acre.
  • Cost for State to thin: $60-$100 per acre.

Mowing and chopping understory vegetation

  • Reduces live and dead fuels effectively for one to several years. However, many problematic species reprout following mowing.
  • Repeat every 1 to 3 years for long-term effectiveness.
  • Cost for mowing and chopping: $100-$500 per acre.

Grazing

  • Effective for reducing grasses and other herbaceous fuels, but does not reduce some shrubs or dead wood, such as branches and logs, effectively.
  • Fuel reduction is short-term since many problematic species resprout following grazing. It is necessary to repeat every 1 to 2 years for long-term effectiveness.
  • Cost to rent livestock: varies by area and type of animal (sheep, goats, or cattle).
  • Cost for purchasing own herd: $200-$500 per head (not including maintenance, fencing, etc.). However, the costs can be offset by revenue gained from selling livestock such as cattle.

This comparison of fuel reduction options is a very simplified summary of the information in the full report. The full report provides cost estimates for each of the fuel reduction options, extensive information on results obtained in multiple studies, special considerations of ecological benefits or costs associated with each treatment, and discussion of the main methods for applying each treatment. By equipping owners of small parcels with information regarding fuel management techniques, the report facilitates informed decision-making about fuel reduction options. If you are considering fuel reduction treatments on your land, please refer to the full technical paper, which is available at:
(http://www.interfacesouth.org/products/pdf.php?id=2912).

Fuel Reduction Options for Landowners Study
This study is being conducted to assess the ecological and cost effectiveness of different fuel reduction treatment options for small landowners in the southern WUI. Fuel management treatments include prescribed fire, herbicide treatments, and mechanical treatments; untreated plots were also included for comparison with the treatments.

This field investigation is being conducted in Alachua County, Florida. Measurements taken on each experimental treatment and untreated plot included percent cover, density and height of gallberry (Ilex glabra), saw palmetto (Serenoa repens), and wiregrass (Aristida beyrichiana), which are abundant shrub and grass species throughout much of the southern Coastal Plain region. Each of the four treatments was applied to different experimental plots in 2002 and the cost associated with each treatment was estimated (see Table 1). The effectiveness and longevity of fuel reduction for each treatment will be compared by re-measuring the variables for each species two times each year for several years.

Table 1.Cost comparison of fuel reduction options (2002).

Treatment Cost per Acre
Prescribed Fire $50
Herbicide $87
Mechanical Mowing $150
Control $0

Summary
In most situations WUI landowners must assume some responsibility for reducing the vegetative fuels around their homes to reduce fire risk on their property. In order to lessen the fuel reduction burden on state and local governments and reduce the risk of catastrophic fires in WUI communities, it is necessary to educate landowners about fuel reduction and the options available for management of vegetative fuels. The fuel reduction options report and research study provide this type of educational information and will contribute to reducing human and property casualties resulting from fires in the wildland-urban interface.

Links to Additional Information about Fire in the Wildland-Urban Interface:


  

Centers for Urban and Interface Forestry
PO Box 110806 / Bldg. 164, Mowry Rd., Gainesville, FL 32611-0806 | 352.376.3213 | 352.376.4536 fax