Fire Ecology Vol. 5, No. 1, 2009 Dicus et al.: Predicted Fire Behavior and Societal Benefits doi: 10.4996/fireecology.0501067 Page 67 RESEARCH ARTICLE PREDICTED FIRE BEHAVIOR AND SOCIETAL BENEFITS IN THREE EASTERN SIERRA NEVADA VEGETATION TYPES Christopher A. Dicus1,*, Kenneth Delfino2, and David R. Weise3 1Natural Resources Management Department, California Polytechnic State University, San Luis Obispo, California 93407, USA 2Urban Forest Ecosystems Institute, California Polytechnic State University, San Luis Obispo, California 93407, USA 3PSW Research Station, USDA Forest Service, Riverside, California 92507, USA *Corresponding author: Tel.: 001-805-756-5104; e-mail: [email protected] ABSTRACT We investigated potential fire behavior and various societal benefits (air pollution remov- al, carbon sequestration, and carbon storage) provided by woodlands of pinyon pine (Pinus monophylla) and juniper (Juniperus californica), shrublands of Great Basin sage- brush (Artemisia tridentata) and rabbitbrush (Ericameria nauseosa), and recently burned annual grasslands near a wildland-urban interface (WUI) community in the high desert of the eastern Sierra Nevada Mountains. Fire behavior simulations showed that shrublands had the greatest flame lengths under low wind conditions, and that pinyon-juniper wood- lands had the greatest flame lengths when winds exceeded 25 km hr-1 and fire transitioned to the crowns. Air pollution removal capacity (PM10, O3, NO2, etc.) was significantly greater in pinyon-juniper stands, followed by shrublands and grasslands. Carbon storage (trees and burned tree snags only) did not significantly differ between pinyon-juniper and burned stands (~14 000 kg ha-1), but will change as burned snags decompose. Annual C sequestration rates in pinyon-juniper stands averaged 630 kg ha-1 yr-1. A landscape-level assessment showed that total compliance with residential defensible space regulations would result in minimal impact to air pollution removal capacity and carbon sequestration due to a currently low population density. Our methodology provides a practical mecha- nism to assess how potential management options might simultaneously impact both fire behavior and various environmental services provided by WUI vegetation. Keywords: air pollution removal, Artemesia tridentata, carbon sequestration, fire behavior, Flam- Map, NEXUS, Pinus monophylla, UFORE, wildland-urban interface Citation: Dicus, C.A., K. Delfino, D.R. Weise. 2009. Predicted fire behavior and societal bene- fits in three eastern Sierra Nevada vegetation types. Fire Ecology 5(1): 67-78. doi: 10.4996/ fireecology.0501067 Fire Ecology Vol. 5, No. 1, 2009 Dicus et al.: Predicted Fire Behavior and Societal Benefits doi: 10.4996/fireecology.0501067 Page 68 INTRODUCTION Minimizing both destructive wildfires and loss of vegetative benefits are competing, yet Burgeoning population growth are affect- integral, objectives in the WUI. We sought to ing fire prone areas in southwestern ecosys- provide a simultaneous evaluation of potential tems. This trend further exacerbates difficul- fire behavior and various benefits provided by ties in fire management in the region, which the predominate woodland, shrubland, and has been complicated by a changing climate grassland vegetation types near Kennedy that has increased the length and severity of Meadows, California, USA, a WUI communi- fire season (Westerling et al. 2006), and by in- ty in the high desert of the eastern Sierra Ne- vasive species that can significantly alter fire vada Mountains in California. Further, we ex- regimes (Brooks et al. 2004). Because of plored how implementation of various defen- mounting suppression costs and private prop- sible space standards could potentially affect erty losses associated with fires in the wild- risk of home ignitions and loss of vegetative land-urban interface (WUI), there is an esca- benefits to the community. lating call there and throughout the western United States to significantly reduce vegeta- METHODS tion both around structures and across the landscape to mitigate the risk of homes burn- Study Area ing (Dombeck et al. 2004). Native vegetation, however, is more than Kennedy Meadows is an isolated, rural fuel for fire, providing various levels of tangi- community located at an elevation of ~1980 m ble and intangible benefits to society. For ex- in the eastern Sierra Nevada along the south ample, vegetation not only enhances commu- fork of the Kern River in the southeast corner nity attractiveness and subsequent value, but of Tulare County, California (36º01’26” N, also removes air pollution (Taha et al. 1997), 118º06’55 W). There are approximately 50 which regularly follows urbanization (Fenger permanent residents and 176 structures in the 1999). Further, vegetation sequesters and community, which range from high-value stores atmospheric carbon, which many be- homes to abandoned trailers. Vegetation with- lieve to be a leading cause in global climate in and immediately surrounding the communi- change (Solomon et al. 2007). ty consists of three primary types: woodlands Thus, land managers are beset with the consisting largely of single-leaf pinyon pine paradox that vegetation is both a liability and (Pinus monophylla) with a small component of an asset to residents living in the WUI. Unfor- California juniper (Juniperus californica); tunately, fuels management is sometimes ac- shrublands dominated by Great Basin sage- complished with little regard to the impact to brush (Artemisia tridentata) and rabbitbrush the multiple societal and environmental bene- (Ericameria nauseosa); and annual grasslands fits that vegetation provides. However, sus- with prolific pinyon pine and juniper snags that tainable land management necessitates recog- resulted from the Manter Fire, which occurred nizing various tradeoffs when modifying veg- in 2000. etation (Dicus and Zimmerman 2007), under- The only documented record of fires burn- standing that post-treatment vegetative compo- ing in the area include the Manter Fire, which sition and structure will influence both poten- burned ~30 000 ha (including 712 ha in the tial fire behavior and benefits such as absorb- Kennedy Meadows community), and the 2003 ing stormwater runoff, removing air pollutants, Michael Fire, which burned ~120 ha east of and sequestering and storing C (Dicus 2008). the community. However, a mosaic of young- Fire Ecology Vol. 5, No. 1, 2009 Dicus et al.: Predicted Fire Behavior and Societal Benefits doi: 10.4996/fireecology.0501067 Page 69 er pinyon-juniper stands, usually less than 20 with standard fuel model loadings, descrip- ha, are readily visible in the surrounding tions, and photo guides (Ottmar et al. 2000, mountains, indicative of extensive past fire ac- Scott and Burgan 2005). We designated pin- tivity in the area. The Manter Fire is especial- yon-juniper woodlands as TU1 (low load, dry ly singed into the conscience of Kennedy climate timber-grass-shrub), shrublands as Meadows’ residents because it was a large, GS2 (moderate load, dry climate grass-shrub), high-intensity, high-severity crown fire that and burned areas as GR1 (short, sparse dry cli- destroyed eight homes in the southern portion mate grass). of the community. Further, the post-fire land- All geographic information system (GIS) scape has shown minimal vegetative regrowth data necessary for landscape-level simulations to date, which, while not abnormal in pinyon and for calibration of weather inputs were sup- pine (Wangler and Minnich 1996), serves as a plied by the Southern Sierra Geographic Infor- constant reminder of the potential threat of mation Cooperative (A. Birkholz, Sequoia and wildfire to the community. Kings Canyon National Parks, unpublished data; hereafter SSGIC). Elevation was ob- Field and Modeling Methods tained from a Digital Elevation Model (DEM). Slope and aspect files were then derived from We installed three randomly located 0.0405 the DEM with ESRI® ArcMapTM (version 9.1). ha plots in each of the primary vegetation types We converted fuel models, canopy cover, and (pinyon-juniper, shrubland, and burned areas canopy base heights in the original data layer that are now grasslands with standing snags) as necessary to reflect field measurements and to collect data pertinent to both fire behavior observations. All gridded raster data layers simulations and vegetative benefit calculations. were 30 m × 30 m. We avoided minor features such as localized Weather, wind, and fuel moisture parame- rock outcrops and bogs. Tree data collected ters utilized in fire behavior simulations were included species, diameter at breast height, to- intended to reflect a scenario similar to that ex- tal height, and height to base of the live crown. perienced in the 2000 Manter Fire. Existing Shrub data included species, canopy height, documentation of the Manter Fire included canopy width, and percent dead. Snag data in- general ranges of temperature, relative humid- cluded species, diameter at breast height, and ity, and winds; a specific National Fire Danger height. All trees and snags found in plots were Rating System Burning Index (BI); and a fire greater than 1.4 m and were thus sampled for progression map (S. Williams, Sequoia Na- diameter at breast height. We also made ocu- tional Forest, personal communication). We lar estimates of overstory canopy coverage therefore used a multi-step process to generate (percent of plot occupied by trees and by and then calibrate specific weather, wind, and shrubs) and ground cover (percent of plot