Prescribed Ecological Burns - Background and Legal Requirements

Prescribed Ecological Burns - Background and Legal Requirements

According to the most recent prescribed burn technical guide, a prescribed burn is defined as “fire applied in a knowledgeable manner to forest fuels on a specific land area under selected weather conditions to accomplish predetermined, well-defined management objectives” (Wade and Lunsford, 1989). Over recent years, the objectives of prescribed burning have expanded to include the maintenance of natural communities and the perpetuation of federal and State listed species. These concerns have stimulated interest in prescribing “natural fire season” burns, often referred to in Florida as “ecological burns.” Natural season fires are assumed to be the most ecologically favorable for perpetuating fire-dependent plant and animal species and maintaining fire­dependent communities. The current trend in ecological burning is to prescribe fires mainly during the shorter lightning-fire or early growing season (May--June) as opposed to the longer wildfire season (March--June), in part to minimize some inherent drawbacks associated with spring drought burns. Because of the potential for conflict among various management objectives, there is growing support for imposing a fire regime characterized by a variable schedule that incorporates burns during various seasons, but favoring the March-June wildfire season (Robbins and Myers, 1989).

Habitat, Wildlife, and Human Benefits. Ecologists have long known that fire is an integral component of the proper ecological management of many of Florida's natural communities. Fire assures the continued health of the plant community, perpetuates plant and animal species diversity, and reduces natural fuel load. Foresters, too, have come to realize that prescribed burning, properly planned and executed, provides numerous benefits to natural communities, wildlife and their habitats, and people. Prescribed burning (1) reduces wildfire risks by consuming accumulated, naturally occurring combustible fuels (termed ``roughage,'' which consists of foliage, twigs, branches, cones, bark, stems, and vines); (2) is the most environmentally sound and cost effective method of preparing natural areas for natural regeneration by eliminating brush and other roughage and by returning nutrients to the soil; (3) controls or eliminates growth of certain pathogens that infest pines and other species (e.g., brown spot needle blight in longleaf pine); (4) is a highly cost effective technique for improving wildlife habitat for many wildlife species (including State and federal listed species) and for maintaining or enhancing existing species diversity; and (5) restores and/or maintains natural communities that are dependent upon periodic fire to retain their biological integrity and diversity (e.g., pine-dominated mesic and xeric communities) by preparing seed bed for pine germination and eliminating competing hardwoods. Both ecologists and foresters agree that, compared to other habitat management techniques, prescribed burning is the most cost effective natural systems management tool (Florida Division of Forestry, n.d.; Robbins and Myers, 1989). When properly planned and executed under suitable weather conditions following recognized smoke management techniques, prescribed burning poses very little hazard to people, property, and air quality (U.S. Forest Service, Southeastern Forest Experiment Station, 1976).

The best prescribed ecological burning fire regime is one that attempts to mimic the natural, early historical fire regime, which was characterized by summer burns in the pine flatwoods (including scrubby flatwoods), dry prairies, and sandhills. Under such a regime, burns are conducted primarily (but not exclusively) during the lightning season (May--June).

Legal Requirements. In Florida, prescribed burning used for the ecological management of fire dependent natural communities is regulated by the Florida Department of Agriculture and Consumer Services' Division of Forestry (DOF) under the Chapter 590, Florida Statutes, and its implementing Chapter 5I-2, Florida Administrative Code. Under an inter-agency operating agreement known as the Open Burning Tri-partite Agreement, open burning permitting, complaints investigations, compliance monitoring and enforcement responsibilities within Hillsborough County are divided among three agencies, the DOF, the Hillsborough County Fire Department, and the Environmental Protection Commission of Hillsborough County (EPC). Among other things, this agreement stipulates that the DOF shall regulate open burning related to silvicultural, range management, and agricultural operations, excluding initial land clearing. Prescribed ecological burning is recognized as a subtype of silvicultural burning and therefore is regulated by the DOF¹

Chapter 590, F.S. sets forth the legal requirements, standards, procedures, and liabilities related to prescribed burning in the Florida Statute. The statute actually includes two sets of provisions regulating prescribed burning, one for non-certified burners (Section 590.125(2)), and another for certified prescribed burn managers (Section 590.126(3)). A “certified prescribed burn manager” (one who successfully completes the DOF prescribed burning certification program) enjoys three key benefits not available to non-certified burners: (1) certified prescribed burn managers quality for a wider range of burning authorization categories (i.e., they can be authorized to conduct burns under the sensitive, open, and forest and range categories, whereas, non-certified burn managers are qualified only for the open category); (2) within each authorization category, they can burn under a less restrictive air dispersion index range (as set forth in the DOF Burning Authorization Categories guide); and (3) they enjoy increased liability protection²

Under the provisions of Section 590.125(3), collectively known as the Florida Prescribed Burning Act, prescribed burning shall (1) be performed only when at least one certified prescribed burn manager is present on site, (2) require a written prescription (a plan for starting and controlling a prescribed burn) be prepared prior to receiving authorization from DOF to burn, (3) be in the public interest and not cause a public or private nuisance when conducted pursuant to State/local air pollution statutes and rules applicable to prescribed burning, and (4) be considered a property right of the property owner if naturally occurring (vegetative) fuels are used and when conducted pursuant to the Act's provisions. No one conducting a prescribed burn pursuant to these provisions shall be held liable for damage or injury caused by fire or resulting smoke, unless negligence is proven.

Under the provisions of Section 590.125(2), any person may legally conduct a prescribed burn provided that he owns or controls the land he plans to burn, has obtained prior authorization from DOF, has provided adequate fire lines, manpower and firefighting equipment to control the fire, monitors the fire until it is extinguished, and confines the fire within the authorized area. Violation of any of these provisions constitutes a second degree misdemeanor. In addition, the violator may be held liable for any damage or injury caused by fire or resulting smoke damage, regardless of whether or not there is criminal prosecution and conviction.

Whether certified or not, no individual is allowed to prescribed burn during a declared emergency drought unless a written permit is obtained from DOF (Section 590.081). In any event, DOF generally will not authorize a prescribed burn (verbally or in writing) during periods of extreme drought conditions.

The DOF's Rural Open Burning Rule (Chapter 5I-2, F.A.C.) implements the provisions of Chapter 590, F.S. Chapter 5I-2 establishes procedures for the authorization of open burning related to agricultural, silvicultural (including ecological management), and rural land clearing activities (see Attachment 1). Under the ``Agricultural and Silvicultural Fires'' section (Section 5I-2.006), prescribed burning is allowed during daylight burning (between 9:00 A.M. and one hour before sunset), although nighttime burning is also permitted under specified circumstances. The written burn prescription required by Section 590.125 must include minimally a description of the stand or site to be burned (including a map), the personnel and equipment to be used, the desired meteorological condition, and the fire behavior factors (including type of burn technique, flame length, and rate of spread). The certified burn manager must also sign the prescription form. The certified burn manager must also evaluate and approve the fire's impacts on related smoke sensitive areas, and he must be present on site during the entire burn. This section also specifies minimum training course and experience required to become a certified burn manager.

Although for most counties Rule 5I-2 also empowers DOF to suspend (after reasonable notice) any DOF-authorized burn whenever weather conditions suitable for prescribed burning deteriorate, in Hillsborough County, the Environmental Protection Commission of Hillsborough County (EPC) retains this right. Specifically, EPC has the authority to temporarily suspend DOF-authorized fires whenever atmospheric or meteorological conditions change so that there is improper diffusion and dispersion of air pollutants which create a condition detrimental to public health, safety or general welfare, or which obscure visibility of vehicular or air traffic (Rules of the EPC, Chapter 1-4, Open Burning, Section 1-4.04(7) and (8)). The rule has additional prohibitions, limitations, and requirements which may apply under certain conditions (Section 1-4.04, 1-4.05, and 1-4.09) (see Attachment 2).

3. Management Guidelines for Fire-Dependent Mesic and Xeric Habitats

The following management guidelines apply to fire-dependent or fire-subclimax plant communities (pine flatwoods, dry prairies, scrubby flatwoods, sandhills, sand pine scrub, and xeric oak scrub) that have been set-aside for preservation. The principal method available to natural systems land managers to maintain, restore, or enhance these dependent habitats is the prescribed burn.

The following guidelines for the prescribed ecological burning of fire-dependent habitat preservation sites have been drawn from forest and ecosystems management technical publications, research papers, and management plans. Reference in particular is made to: the Hillsborough River State Park Unit Plan (Florida Department of Natural Resources, Division of Recreation and Parks, n.d.a), the Myakka River State Park Unit Plan (Florida Department of Natural Resources, Division of Recreation and Parks, n.d.b), The Nature Conservancy's Fire Management and Research Program (The Nature Conservancy, n.d.), including a comprehensive literature review on the ``Seasonal Effects of Prescribed Burning in Florida: a Review'' (Robbins and Myers, 1989), A Guide for Prescribed Fire in Southern Forests (Wade and Lunsford, 1989), Southern Forestry Smoke Management Guidebook (U.S. Forest Service, Southeastern Forest Experiment Station, 1976), and the Basic described Fire Training Manual (Florida DOF, n.d.). For site-specific applications, it is recommended that these sources be consulted and that natural systems land managers experienced in the use of prescribed burning prepare the burn plan and oversee its implementation and post-fire evaluation. It should be noted that the latter three sources are prepared by and are largely for forestry applications. Therefore, some of their recommendations and guidelines (particularly with respect to preferred burning season) are more suitable for managing forests for the production of silvicultural products and may be inappropriate for managing natural ecological communities.

A prescribed burn program for fire-dependent natural communities sets forth a burn plan, establishes program maintenance and evaluation procedures, and takes into account expected environmental effects, weather and fuel considerations, firing techniques, and smoke management.

At least 24 hours prior to setting a prescribed burn, the landowner (or his duly authorized agent) must obtain a verbal authorization from DOF, as required by Chapter 590, F.S. and Chapter 5I-2, F.A.C.. Following receipt of DOF authorization, the landowner must notify EPC. Such notification should minimally identity the DOF authorization number and the responsible party, locate the proposed burn site and describe its size and the anticipated duration of the burn, and identify any measures to be taken to comply with restrictions in the EPC Open Burning Rule (Chapter 1-4). The landowner should also forward EPC a copy of the written burn prescription (including a smoke screening plan) along with any other relevant information specific to the burn event. To help minimize air quality effects and other potential nuisances, it is preferred that the size of the burn unit should be such that the fire can be set and extinguished within one day. This may necessitate that large tracts be subdivided into two or more one-day sized burn units.

A written burn prescription/smoke screening plan should be formulated in accordance with established professional ecosystems-oriented forest management practices. Copies of the plan should be sent to EPC as part of the notification process. Because prescribed burning is a highly technical job requiring detailed understanding of fire and smoke behavior, suppression techniques, and the environmental effects of fire, it is preferred that the burn plan be prepared by a DOF-certified prescribed burn manager, or, if not, a person experienced in prescribed burning. The U.S. Forest Service guide provides two sample understory burning unit plan forms, one a “simple” form appropriate for small burns within a large landholding that does not include public roads, the other a form for more complex burns (Wade and Lunsford, 1989).

In light of the potential for conflict among various management objectives, particularly the need to ensure habitat maintenance, listed species perpetuation, and public safety and acceptance (e.g., fire control, smoke management, and public perceptions about fires), it is recommended that a prescribed fire regime for maintaining local and regional community diversity follow a mixed growing season/dormant season schedule, but one favoring the March-June wildfire season (Robbins and Myers, 1989). The particular seasonal mix to follow depends on site-specific conditions and immediate management concerns. However, burns during July through September generally should be avoided because weather conditions are less predictable during the rainy season and thereby pose a greater potential threat to air quality.

The frequency of prescribed burns (or fire return interval) varies depending upon the particular fire-dependent community and the particular post-burn benefits desired. For natural community and wildlife habitat maintenance, the following burn interval ranges are recommended by the Nature Conservancy Fire Management and Research Program and are incorporated in the Florida DOF's Basic Prescribed Fire Training Manual:

 Pine Flatwoods: 1-7 years

 Dry Prairies: 1-4 years (or less frequently to enable succession to pine flatwoods)

·           Scrubby Flatwoods: 8-25 years

·           Sand Pine Scrub (including Xeric Oak Scrub): 26-100 years

·           Sandhill: 2-5 years

An initial fuel reduction burn is recommended during the winter before the prescribed burning cycle is begun if an excessive build-up of forest fuels is present. If additional fuel reduction and wildlife habitat improvements are desired, the burn (fire return) interval should be shortened. If a site has been invaded by hardwoods that have grown too large to be killed by burning, their removal by mechanical means may be desirable. Early growing season burns are recommended to reduce the abundance of understory species and restore an open, uncluttered understory rich in grasses, forbs, and herbs while retaining some understory shrub vegetation to provide cover, habitat diversity, and food for wildlife.

To minimize possible negative impacts on nesting birds during the nesting season (April-June), the following precautions should be followed: reduce the size of the burn units, ensure patchy burns (leaving the nesting areas as unburned patches), and, if necessary, burn following nesting period. The guidelines in Appendix C should be consulted to ensure that site-specific habitat maintenance activities will not adversely impact viable populations of State and federally listed species.

Burn control conditions should be such as to allow duplication of the vegetative mosaic (i.e., burned/unburned patches) that typified early historic fire-dependent communities. Although backing fires are the preferred technique, other techniques (which include strip­heading, flanking, point source, and ring fires), alone or in combination, may be more appropriate. The particular technique(s) to employ at a given site should be determined on a case-by-case basis. Precautions (e.g., buffers, use of backfires, use of preferred weather condition “windows”, and vigilant monitoring) should be taken near buildings.

There is no minimal acreage threshold below which a prescribed burn cannot be safely performed. However, on certain sites or portions of sites, shape, configuration, or adjacent land use/cover factors may preclude the use of prescribed burning as a habitat management option. Although less cost effective, mechanical techniques (e.g., diking, chopping, mulching and/or raking) may be substituted for prescribed burning when adequate fire safeguards for the protection of adjoining property cannot be secured.

Burning during the natural wildfire season (March-June) presents special fire control problems which necessitate certain precautions be taken. During late spring (March-April), these problems primarily entail managing heavy fuel loads, preventing fires from damaging sensitive wetlands (particularly those underlain by muck or peat), and coping with erratic wind and precipitation patterns (particularly during the afternoon). Fire intensity, scorch, and spotting potential (i.e., fires jumping fire line perimeter) can be minimized with the appropriate fuel reduction measures (initial dormant season burn), proper design and adequate preparation of burn units to allow for unexpected windshifts, and applying fire prediction principles when developing the burn program. During the summer, the unpredictable weather, and, to a lesser extent, narrow burn windows and ineffectual backing fires due to high moisture and fine fuel moisture are the chief concerns. With proper planning, however, the problems related to growing season burns can be greatly minimized.

Federal and State forest services prescribed burn technical sources listed in the references should be consulted to precisely determine optimal burn times, weather conditions, etc. for site specific applications. In general, the preferred weather condition ``windows'' recommended by the U.S. Forest Service for prescribed burns in support of forest resource (primarily silvicultural) management are as follows:

·         an in-stand wind of 1-3 mph, 30-55% relative humidity

·         temperature of less than 60 F (if a winter burn)

·         damp soil moisture conditions

·           10-20% fine-fuel moisture levels

·         slightly unstable to neutral air mass stability

·         a mixing height of between 1700-6500 feet above ground

·         a transport windspeed of between 9-20 mph

·         the preferred time of day to ignite prescribed fires is between 10 a.m. and noon, after the morning dew is evaporated (Wade and Lunsford, 1989)

While many of these preferred “windows” more typically occur during winter, there are usually periods during the late spring and early summer (in normal years) when burns can also be safely conducted. The Nature Conservancy's proposed “burn schedule for upland longleaf pine/wiregrass community” (including pine flatwoods and sandhills) provides an approach to designing a multi-season burn regime (Appendix II in Robbins and Myers, 1989). This approach identifies assumptions and conditions for a burn program which is designed to maintain the pine/wiregrass community. It features a randomized table to introduce variability in season, frequency, and pattern of prescribed burns, which helps minimize potentially negative effects that could result from strictly adhering to a fixed burning schedule. The schedule also distinguishes between mesic, mesic-xeric, and xeric site types.

The recommended minimum site size for safe execution of prescribed burns will depend on fuel and weather conditions, as well as adjacent land uses. As indicated above, minimum burn unit size per se is not a limiting factor; sites as little as an acre can be safely burned, providing that all necessary precautions are taken to fully minimize fire hazards to adjoining properties. Careful site-specific evaluation should be made to determine if prescribed burning can be safely and effectively conducted, or whether alternative means of habitat maintenance or restoration (i.e., mechanical) should be substituted. Unburned setback buffers may require mechanical techniques to supplement habitat maintenance. The unburned buffers also enhance the habitat value by heightening edge effect.

Because prescribed fires can potentially pollute the air, effective smoke management procedures which accounts for smoke plume direction, identifies smoke-sensitive areas, and selects most appropriate fuel type, must be established and implemented (A map showing smoke sensitive areas in Hillsborough County can be obtained from EPC, Air Management Division).