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Fire Regime Condition Class (FRCC) — Frequently Asked Questions (FAQs)

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This compilation of frequently asked questions (FAQs) provides answers to common questions about FRCC. Please check these FAQs for answers to your questions before contacting the Help Desk.

What is the importance or application of FRCC nationally?

FRCC continues to be used as a metric or indicator of land health among federal agencies.    As such, FRCC is used as a reporting element for field units that report data upwards within the National Fire Plan Operations and Reporting System (NFPORS) and Forest Service Activity Tracking System (FACTS).  Since 2003, at the national level, FRCC has been a performance measure used for summarization of accomplishments (for example, the number of acres treated within certain combinations of fire regime groups and condition classes).  Across the federal agencies, FRCC appears to be firmly established in use and will likely continue to be.  Certain private organizations, such as The Nature Conservancy, have applied FRCC in conservation planning on non-federal lands.  However, the use of FRCC is most common among federal agencies for reporting and land health summarization.

How can FRCC be assessed?

FRCC can be calculated using one of three broad approaches.  The first technique is using the FRCC standard landscape worksheet method for manually calculating FRCC.  The second method is using the non-spatial FRCC software application, which summarizes FRCC at multiple scales in a tabular format.   The third technique available is spatially mapping FRCC in GIS using the LANDFIRE biophysical settings and succession class grids as inputs.

Is the FRCC methodology too opaque or simplistic to be meaningful?

FRCC developers and collaborators have worked to insure transparency in the FRCC methods.  Beginning in 2002, federal scientists began working to integrate accepted natural resource monitoring techniques in the FRCC assessment methods.  In addition, FRCC developers have worked closely with LANDFIRE scientists to align field and mapping techniques in a methodology commonly known as the “guidebook method.”  During this period, a guiding principle influencing the FRCC project has been that the methods would use simple metrics that could be readily understood by a wide range of resource managers and specialists.  Methods updates occur periodically based upon sensitivity testing and user feedback.   There are limitations to the inferences that can be drawn based upon FRCC findings.  However, important precepts of landscape ecology, such as patch dynamics, scale, and disturbance regimes, are incorporated into the FRCC methods.

What kinds of support are available to FRCC users?

NIFTT maintains a help desk that typically responds to users within 24 hours of initial contact. In addition, some of the FRCC software tools have user friendly, built-in Help functions. In addition, users can take the online course Fire Regime Condition Class, which introduces the participant to the theories and principles behind FRCC and also teaches the Standard Landscape Worksheet Method for assessing condition class on the landscape. Please visit the Training section of this website to learn more.

Is the FRCC methodology too specialized for most managers?

Is the FRCC methodology too esoteric / over-specialized for most managers? In other words, is it difficult to understand and use?

NIFTT believes that the FRCC methodology and associated forms and tools were designed to be user-friendly and relevant to management. For example, the FRCC methodology is not unlike other well established methods that evaluate watershed conditions, range conditions, and other resource specialties. In addition, note that the simple similarity and departure indices used by the FRCC method have existed in the realm of vegetation ecology since at least the 1950s.

Who developed the BpS reference condition models and how were they developed?

Who developed the default biophysical settings (BpS) reference condition models and how were they developed?

The development of reference condition models for the various biophysical settings (BpS) (or Potential Natural Vegetation Groups [PNVG]) was a long and arduous process that took nearly a decade to complete. The goal was to thoroughly describe the disturbance-maintained plant communities that existed for thousands of years before EuroAmerican settlement. As described in Chapters 2 of the FRCC Guidebook, numerous workshops were held in which local ecologists used available literature and expert knowledge to model and summarize fire regimes, succession class structure and composition, and other biophysical traits for all major types in the U.S. (See the following related FAQ.)

Have the default reference condition values been peer reviewed?

Have the default reference condition values been peer reviewed?

Yes. The model development process mentioned above included an extensive peer review process between 2003 and 2010. In addition, the models have been used for various research purposes that have been described in publications such as USDA Forest Service General Technical Reports and peer-reviewed professional journals.

Can I develop my own reference condition models?

Can I develop my own reference condition models, or is such modeling too complex for the average user?

Users can develop their own models under the formal protocol described in the FRCC Guidebook (see Chapter 2 and Appendix C). The modeling software used for this process is the Vegetation Dynamics Development Tool (VDDT; available at, which is relatively user-friendly and free. Also note that some federal agencies and The Nature Conservancy's Fire Learning Network have provided a number of VDDT training workshops to date. Some agencies also have experts who can assist with such modeling, which requires both local data and user background knowledge about vegetation structures, succession rates, fire regimes, and fire effects at all scales.

Why use historical range of variation in calculating departure?

Why does the FRCC method use the historical range of variation (HRV) in calculating departure, since HRV reflects somewhat cooler climatic conditions that may never occur again?

HRV is used because it is the best currently available information on sustainable landscapes. We fully realize this is not the same range of variation that could occur at this point in time. In response, some researchers are starting to model what the current (or future) range of variation will be, and as these results become available and peer-reviewed, we will incorporate them into the FRCC method. In addition, many ecosystems are now so altered from sustainable ranges that great accuracy in determining departure is not really necessary, and hence the relatively simple FRCC metrics will suffice. (See the following related FAQ.)

Is HRV irrelevant since ecosystems may change due to climate change?

Is HRV irrelevant since ecosystems may change unpredictably due to climate change?

No, because the historical range of variation is still a good measure of land capability and sustainability. Climate change will certainly have effects, but they will likely be gradual changes over time. NIFTT fully agrees, however, that the FRCC methodology must be revised in the future to reflect changing conditions and incorporate new estimates of the range of variation as such data become available.

Shouldn't HRV be used only for context when interpreting FRCC outcomes?

Shouldn't the historical (or natural) range of variation be used only for context when interpreting FRCC outcomes - and not for actual management targets?

FRCC developers consistently stress during trainings that HRV does not represent the desired future condition in every management situation. In other words, management objectives are constantly influenced and shaped by social, economic, and other resource concerns. (See the following related FAQ.)

Are the federal agencies required to convert all FRCC 3 and FRCC 2 lands back to FRCC 1?

Are the federal agencies required to convert all FRCC 3 and FRCC 2 lands back to FRCC 1?

No. Restoring all federal lands to condition class 1 in order to emulate historical conditions is neither feasible nor universally desirable. For example, the scope of the problem in many areas is simply too large - especially in view of funding and human resource limitations. Also, management objectives (such as fire hazard mitigation) often do not include restoration and maintenance of natural conditions.

Why use stand-scale fire frequency for characterizing landscape-scale events?

Why do the reference condition models and FRCC assessments use stand-scale fire frequency for characterizing landscape-scale occurrence?

Representative stand metrics, such as mean MFI, gathered from multiple sample sites (Barrett and others 1997), can be used for characterizing fire frequency at multiple scales. For example, stand MFIs can be used to determine a fire cycle metric (Heinselman 1973; Heinselman 1981; Brown and Smith 2000) for any given BpS regardless of landscape size (Brown and others 1994; Barrett and others 1997; Morgan and others 1998). In essence, the stand MFI metric serves as a lowest common denominator for characterizing fire frequency at multiple scales, which is useful for FRCC purposes because assessment landscapes can vary widely in size.

Barrett, S.W.; Arno, S.F.; Menakis, J.P. 1997. Fire Episodes in the Inland Northwest (1540-1940) based on fire history data. Gen. Tech. Rep. INT-GTR-370. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station.

Heinselman, M.L. 1973. Fire in the virgin forests of the Boundary Waters Canoe Area, Minnesota. Quaternary Research. 3: 329-382.

Heinselman, M.L. 1981. Fire intensity and frequency as factors in the distribution and structure of Northern ecosystems. In: Fire regimes and ecosystem properties: conference proceedings; 1978 Dec. 11-15; Honolulu, HI. Gen Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 7-57.

Brown, J.K.; Smith, J. Kapler, eds. 2000. Wildland fire in ecosystems: effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42 vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 257 p.

Brown, J. K.; Arno, S. F.; Barrett, S. W.; Menakis, J. P. 1994. Comparing the Prescribed Natural Fire Program with presettlement fires in the Selway-Bitterroot Wilderness. Int. J. Wildland Fire 4(3): 157-168.

Barrett, S.W.; Arno, S.F.; Menakis, J.P. 1997. Fire Episodes in the Inland Northwest (1540-1940) based on fire history data. Gen. Tech. Rep. INT-GTR-370. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station.

Morgan, P.; Bunting, S.C.; Black, A.E.; Merrill, T.; Barrett, S.W. 1998. Past and present fire regimes in the Interior Columbia River Basin. In: Close, K.; Bartlette, R.A., eds. Fire management under fire (adapting to change): Proceedings of the 1994 Interior West Fire Council meeting and program; 1994 November 1-4; Coeur d' Alene, ID. Fairfield WA: International Association of Wildland Fire: 77-82.

What are examples of FRCC-related policies of land management agencies?

What are some examples of FRCC-related policy requirements in the various land management agencies?

FRCC is applied by federal agencies at a number of scales. At the broadest scale, FRCC data serve as inputs for national allocation models such as the Ecosystem Management Decision Support System (EMDS). And, at finer scales, FRCC is required for accomplishment reporting across federal agencies, and in some agencies' planning processes. Currently, FRCC is a required reporting element for Department of Interior natural resource agencies in the National Fire Plan Operations and Reporting System (NFPORS). FRCC is also a required reporting element in the USDA Forest Service Activity Tracking System (FACTS). In both of those databases, pre-and post-treatment condition classes and fire regimes data are required for areas subject to fuel management treatments. The Bureau of Land Management requires FRCC summaries in Land Management Plans and Fire Management Plans. In those documents, condition class acres within each BpS and associated fire regime groups are required data elements.

Are FRCC metrics useful for evaluating fire hazard in wildland-urban interface areas?

Are FRCC metrics useful for evaluating fire hazard in wildland-urban interface (WUI) areas and elsewhere?

No, FRCC is strictly a measure of ecological departure from historical reference conditions. Although FRCC is not a fire hazard metric, indirect inferences about potential fire behavior or effects can sometimes be made when analyzing the condition class results for a given BpS.

How does FRCC Guidebook version 3.0 improve upon previous versions?

How does FRCC Guidebook version 3.0 improve upon previous versions?

Based upon user feedback, the FRCC working group has attempted to improve the FRCC assessment process in several ways. First, the number of fields used in both the forms and software tools has been reduced to lessen clutter and improve ease of use. Fields which were duplicative or unnecessary were deleted. Next, consistency in methodology between the Standard Landscape Worksheet and Standard Landscape Mapping methods was improved, including the incorporation of fire regimes data into the GIS mapping tool. Finally, the FRCC Software Application and FRCC Mapping Tool were improved to both produce summary reports of FRCC findings for watersheds, fire management units, and other assessment areas (see FRCC Guidebook Chapter 4). NIFTT also considered user feedback and conducted sensitivity testing to develop new FRCC methods and calculations, as described in chapters 2 and 3 of the FRCC Guidebook. (See the related following FAQ.)

Version 3.0 contains two new algorithms: are previous FRCC assessments still valid?

Since version 3.0 contains two new algorithms, does that mean that previous FRCC assessments are no longer valid? And if not, how should re-assessments be conducted for those FRCC Landscapes?

Whether your previous FRCC outputs are still valid is up to you to decide based on management objectives, on landscape and stand conditions, and on other factors. Be aware, however, that your old output data might well differ substantially from any new data generated by the FRCC Guidebook version 3.0 algorithms. This is especially true of FRCC Mapping Tool outputs, because previous tool versions were unable to process fire frequency and severity data. Note that two options exist for conducting re-assessments: 1) use the version 3.0 methods and tools to re-analyze both the original input data and any subsequently updated inputs (recommended approach); or 2) continue using the old FRCC methods and tools to conduct the re-assessment.

What is the difference between Field 70 (Class) and Field 72 (Condition)?

What is the difference between the "Stratum Regime Condition Class" (field 70) and the "Stratum Fire Regime Condition Class" (field 72)?

As explained in FRCC Guidebook Chapter 3, Stratum Regime Condition Class reflects the departure classification for the fire regime component only (that is, frequency departure + severity departure / 2). In contrast, Stratum Fire Regime Condition Class reflects the average of the vegetation and fire regime departures (vegetation departure + regime departure / 2), which is the endpoint diagnosis for the Stratum.

Are GIS-based FRCC assessments more accurate than field-based assessments?

Are GIS-based FRCC assessments more accurate than field-based assessments?

The spatial outputs generated by the FRCC Mapping Tool certainly can be more informative than the non-spatial data produced by field-based FRCC assessments, However, the tool does not always produce more accurate FRCC outputs. As discussed in FRCC Guidebook Chapter 2, imagery-derived inputs have inherent limitations (Schmidt and others 2002; Menakis and others 2003; Menakis and others 2004; Rollins and others 2004; Provencher and others 2008; Blankenship and others 2009; Provencher and others 2009). Consequently, prospective users of the FRCC Mapping Tool should plan to validate their input and output data by using ground surveys, additional locally derived data (such as from stand exams), and local expert knowledge whenever possible.

Schmidt, K.M.; Menakis, J.P.; Hardy, C.C.; Hann, W.J.; Bunnell, D.L. 2002. Development of coarse-scale spatial data for wildland fire and fuel management. Gen. Tech. Rep., RMRS-GTR-87. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

Menakis, J. P.; Osborne, D.; Miller, M. 2003. Mapping the Cheatgrass-Caused Departure From Historical Natural Fire Regimes in the Great Basin, USA. pp. 281-287 In: Omi, Philip N.; Joyce, Linda A., technical editors. 2003. Fire, fuel treatments, and ecological restoration: Conference proceedings; 2002 16-18 April; Fort Collins, CO. Proceedings RMRS-P-29. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 475 p.

Menakis, J. P.; Miller, M.; Thompson, T. 2004. Mapping relative fire regime condition class for the Western United States. In: Greer, Jerry Dean, ed. Remote sensing for field users; proceedings of the tenth Forest Service remote sensing applications conference; 2004 April 5-9; Salt Lake City, UT. Bethesda, MD: American Society of Photogrammetry and Remote Sensing. CD-ROM.

Rollins, M. G.; Keane, R. E.; Parsons, R. A. 2004. Mapping fuels and fire regimes using remote sensing, ecosystem simulation, and gradient modeling. Ecological Applications: Vol. 14, No. 1, pp. 75-95.

Provencher, L.; Campbell, J.; Nachlinger, J. 2008. Implementation of mid-scale fire regime condition class mapping. International Journal of Wildland Fire 17: 390-406.

Blankenship, K.; Smith, J.; Shlisky, A.; Swaty, R. 2009. Assessing Fire and Biodiversity Conservation for the Conterminous United States. pp. 343-357 In: Gonzalez-Caban, A., Technical Editor. Proceedings of the third international symposium on fire economics, planning, and policy: common problems and approaches. Gen. Tech. Rep. PSW-GTR-227 (English). Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 395 p.

Provencher, L.; Blankenship, K.; Smith, J.; Campbell, J.; Polly, M. 2009. Comparing locally derived and LANDFIRE geo-layers in the Great Basin, USA. Fire Ecology 5(2): 126-132.

Why is FRCC scale-dependent, and how does analysis scale affect Mapping Tool outputs?

Why is FRCC scale-dependent, and how does analysis scale affect FRCC Mapping Tool outputs?

As described in FRCC Guidebook chapters 2 and 3, stratum condition class outcomes can be greatly affected by the size of the reporting units that are used for summarizing the vegetation composition. That is, ecologically appropriate analysis scales should be used whenever possible. (A notable exception occurs with the LANDFIRE National FRCC layer, as described in the following FAQ.) For example, subwatershed-size units are likely appropriate for analyzing BpS types in Fire Regime Groups I and II, because associated fire and patch sizes are usually relatively small. Conversely, large summary units such as sub-basins should be used for analyzing BpS types in Fire Regime Group V, because fire and patch sizes are often quite large. Also be aware that the use of inappropriate analysis scales can produce substantially different and partially erroneous FRCC outcomes than might otherwise occur. For instance, user-induced error can occur when the summary units are too small to potentially exhibit the full range of S-Class compositions that occurred in the natural landscape. In such cases, the mapping tool would likely generate excessive amounts of condition class 3 - especially where stand replacement fires have promoted large expanses of just one succession class.

Does the LANDFIRE National layer differ from Mapping Tool layers for local assessments?

How does the LANDFIRE National FRCC layer differ from the various FRCC layers produced by the FRCC Mapping Tool for local assessments?

As described in Appendix E of the FRCC Guidebook, the LANDFIRE FRCC layer that covers the entire U.S. is based on vegetation composition only, not also on fire regime inputs as occurs with locally based assessments. In addition, S-Class compositions for the many hundreds of BpS types across the U.S. were summarized according to very large areas (such as entire LANDFIRE mapping zones) because smaller summary units such as watersheds would have been impractical from a logistics standpoint. Given the above limitations, the LANDFIRE FRCC layer is useful mostly for regional to national-level planning, whereas for local planning purposes, the FRCC Mapping Tool can produce FRCC layers for three scales that range from stands to relatively large landscape units for a given assessment area.


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