Historical Pyrogeography of Texas, Usa
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Fire Ecology Volume 10, Issue 3, 2014 Stambaugh et al.: Historical Pyrogeography doi: 10.4996/fireecology.1003072 Page 72 RESEARCH ARTICLE HISTORICAL PYROGEOGRAPHY OF TEXAS, USA Michael C. Stambaugh1*, Jeffrey C. Sparks2, and E.R. Abadir1 1 Department of Forestry, University of Missouri, 203 ABNR Building, Columbia, Missouri 65211, USA 2 State Parks Wildland Fire Program, Texas Parks and Wildlife Department, 12016 FM 848, Tyler, Texas 75707, USA * Corresponding author: Tel.: +001-573-882-8841; e-mail: [email protected] ABSTRACT RESUMEN Synthesis of multiple sources of fire La síntesis de múltiples fuentes de informa- history information increases the pow- ción sobre historia del fuego, incrementa el er and reliability of fire regime charac- poder de confiabilidad en la caracterización de terization. Fire regime characterization regímenes de fuego. La caracterización de es- is critical for assessing fire risk, identi- tos regímenes es crítica para determinar el fying climate change impacts, under- riesgo de incendio, identificar impactos del standing ecosystem processes, and de- cambio climático, entender procesos ecosisté- veloping policies and objectives for micos, y desarrollar políticas y objetivos para fire management. For these reasons, el manejo del fuego. Por esas razones, hici- we conducted a literature review and mos una revisión bibliográfica y un análisis es- spatial analysis of historical fire inter- pacial de los intervalos históricos del fuego en vals in Texas, USA, a state with diverse Texas, EEUU, un estado con diversos ambien- fire environments and significant tes de fuego y desafíos importantes en el tema fire-related challenges. Limited litera- de incendios. La literatura que describe regí- ture describing historical fire regimes menes históricos de fuego es limitada, y muy exists and few studies have quantita- pocos estudios han determinado cuantitativa- tively assessed the historical frequency mente la frecuencia histórica de fuegos de ve- of wildland fire. Written accounts pro- getación. Algunos escritos proveyeron de in- vided anecdotal fire information that is formación anecdótica de incendios que es es- spatially and temporally constrained. pacial y temporalmente restringida. Tres bases Three spatial datasets depicting historic de datos que presentan intervalos históricos mean fire intervals (MFIs) showed medios en la ocurrencia de incendios (MFIs), agreement in that the majority of Texas muestran coincidencias sobre que en la mayor consisted of frequent fire regimes parte de Texas, los incendios son frecuentes (MFIs = 1 yr to 12 yr), and that a gradi- (MFIs = 1 a 12 años), y que existe un gradien- ent of decreasing fire return intervals te de decrecimiento en la frecuencia de incen- existed from west to east. Much poten- dios de oeste a este. Afortunadamente existe tial likely exists for acquiring fire his- mucho potencial para adquirir datos históricos tory data in the Piney Woods region, de incendios en las regiónes llamadas Piney the Oak Woods and Prairies region, Woods, Oak Woods and Prairies, y de los pas- and the mountain ranges of the Trans tizales montañosos de la región llamada Trans Fire Ecology Volume 10, Issue 3, 2014 Stambaugh et al.: Historical Pyrogeography doi: 10.4996/fireecology.1003072 Page 73 Pecos region. These data will be valu- Pecos. Estos datos serán invaluables para me- able for improving fire regime charac- jorar la caracterización del régimen de incen- terization to guide fire planning and dios y servirán para guiar los procesos de pla- budget processes, for the restoration nificación y la elaboración de presupuestos, and maintenance of fire-adapted land- para la restauración y mantenimiento de paisa- scapes, and for informing fire preven- jes adaptados al fuego, y para informar activi- tion and education activities. dades de educación y prevención de incendios. Keywords: fire regimes, literature review, map, mean fire interval, natural subregions, restoration Citation: Stambaugh, M.C., J.C. Sparks, and E.R. Abadir. 2014. Historical pyrogeography of Texas, USA. Fire Ecology 10(3): 72–89. doi: 10.4996/fireecology.1003072 INTRODUCTION Texas ecosystems, little work has been done to describe and synthesize historical fire regime Characteristics of historical fire regimes characteristics. In this paper, we focus on in- underlie a multitude of present day societal formation from prior-to EAS influences (i.e., and natural resource challenges (Wildland Fire on ignitions, fuels, suppression) because it de- Leadership Council 2014). Historical fire re- scribes the historical fire characteristics and gime data aid in assessing fire risk (Hardy ecosystem processes, the legacies for which 2005), identifying climate change impacts are still evidenced (e.g., seedbanks, soil condi- (Westerling et al. 2006, Guyette et al. 2014), tions, relict long-lived organisms). Our objec- understanding ecosystem processes (Bond and tive was to review and integrate literature and Keeley 2005), and developing policies and pri- data describing the historical fire return inter- orities for fire and land management (Wildland vals of Texas, thereby aiding future efforts to- Fire Leadership Council 2014). Synthesis of wards restoring fire regimes, conserving multiple sources and types of information in- fire-adapted species and communities, and in- creases the power and reliability of historical forming fire risk and prevention. fire regime interpretation (Morgan et al. 2001) and, because fire regimes are dynamic, long- METHODS term information is needed to define them. Since Euro-American settlement (EAS), his- We reviewed and summarized published torical fire regimes throughout North America literature describing historical fire regimes in have been highly altered to lengthened fire in- the state of Texas. We searched agricultural tervals and changed seasonality of occurrence and biological literature databases (Agricola, (Stewart 2002, Keane et al. 2007, Knapp et al. Scopus, Biological Abstracts, BioOne) for 2009), making them difficult to quantitatively keywords related to fire and the ecosystems of define, particularly through analysis of modern Texas. We conducted further literature search- data. es using reference citations within papers. The state of Texas, USA, presents unique Over one hundred sources of fire information fire research opportunities because it has per- were reviewed including travelers’ journals, haps the greatest diversity of fire regimes, fire federal agency proceedings, theses and disser- conditions, and fire concerns represented in tations, and scientific publications. We orga- the US (Wildland Fire Leadership Council nized fire regime information by Texas’ natu- 2014). Even though fire is generally regarded ral subregions (LBJ School of Public Affairs as a historically important disturbance in most 1978) (Figure 1) because of the close relation- Fire Ecology Volume 10, Issue 3, 2014 Stambaugh et al.: Historical Pyrogeography doi: 10.4996/fireecology.1003072 Page 74 Figure 1. Texas natural regions and subregions and historical fire return intervals. Natural regions and subregions of Texas were used to stratify descriptions of historical fire regime literature and geodatabases. Refer to Table 1 for region and subregion names (source: Lyndon B. Johnson School of Public Affairs Pol- icy Research Project Report No. 31, Preserving Texas’ Natural Heritage). The three historical fire fre- quency maps are: Frost (1988), pre-settlement fire frequency regions (see methods and original publica- tion for description of the development of this coarse-scale map; PC2FM, pre-settlement fire frequency estimates by Guyette et al. (2012); and LANDFIRE National (Keane et al. 2002) Mean Fire Interval Map. See methods for more detailed descriptions. Fire Ecology Volume 10, Issue 3, 2014 Stambaugh et al.: Historical Pyrogeography doi: 10.4996/fireecology.1003072 Page 75 ship between fire environment conditions and spans. Simulation results were summarized natural subregion characteristics (e.g., vegeta- into high-resolution estimates of historic tion, climate, landforms, and soils). Organiz- MFIs. The LANDFIRE MFIs represent the ing the review by natural subregions was also average period between fires under the pre- an attempt to make the information useful to a sumed historical fire regime. MFIs are derived wide range of fire information user groups. from vegetation and disturbance dynamics The relatively large areas of natural subregions simulations at a 30 m resolution using LAND- typically allowed consideration of multiple SUMa landscape fire succession model sources of information. In the absence of (Keane et al. 2002, Hann et al. 2004). qualitative or quantitative information from For each historical fire interval source, ras- Texas, results of studies from regions with ter grid data of MFIs were used to calculate similar vegetation types were included. zonal statistics by natural subregion using Arc- In addition to qualitative historical fire in- GIS software (ESRI 2011; Table 1). Raster formation from published literature, we evalu- cell size varied among sources (Table 1). Min- ated three sources of historical fire interval es- imum, maximum, and majority MFIs were de- timates that included maps or geodatabases. termined for each natural subregion. Because The first source was Frost’s (1998) first ap- of the finer resolution of LANDFIRE data proximation of pre-settlement fire frequency (i.e., 30 m2), a high range of MFIs resulted for regions of the United States based on fire his-