Guide for Quantifying Fuels in the Sagebrush Steppe and Juniper Woodlands of the Great Basin

2 Introduction SageSTEP (Sagebrush Steppe Treatment Evaluation Project) is an interdisciplinary, fi ve-year study to evaluate the effects of various restoration treatments in sagebrush steppe communities of the Great Basin (McIver et al. 2005). Sagebrush steppe, characterized by dry, open expanses dominated by sagebrush plant communities, is one of the most threatened vegetation types in North America (Noss et al. 1995). Loss of sagebrush steppe is often attributed to shifting fi re regimes as a result of nonnative grass invasion, especially cheatgrass (Bromus tectorum), and pinyon pine (Pinus edulis and Pinus monophylla) and juniper (Juniperus spp.) encroachment (Pellant 1994, Miller and Tausch 2001). SageSTEP is funded by the Joint Fire Science Program and involves collaboration with fi ve universities, six federal agencies, and one non-profi t organization. The overall goal of SageSTEP is to identify abotic and biotic thresholds that infl uence the sustainability of sagebrush steppe communities and provide information to managers, ranchers, and the general public to help restore sagebrush steppe to a healthier, more diverse ecosystem. Cheatgrass has invaded nearly 25 million acres of the Great Basin (Olson 2008). Cheatgrass is able to gain a foothold in native communities by providing a continuous bed of fi ne fuel susceptible to fi re at a time when it is most harmful to native perennials (Peters and Bunting 1994) because of its ability to germinate and establish before native perennial grasses (Bradford and Lauenroth 2006) and because it cures earlier in the growing season than perennials (Mutch 1967). Figure 1. SageSTEP Site Map; for reference with site names. Site specifi c information is available at http://www.sagestep. org/locations.html. Introduction 3 Cheatgrass dominance has shifted the mean fi re return interval from 50–100+ years, in healthy Wyoming big sagebrush dominated communities, to less than 10 years (Whisenant 1990). Increased fi re frequency perpetuates cheatgrass expansion, quickly depletes the sagebrush seed bank, and converts native vegetation to an annual grassland (Whisenant 1990). This is the concern in the Sagebrush/Cheatgrass locations (Figure 1). These will be referred to as the ‘sagebrush sites’ for the rest of the Guide. Woodland encroachment of pinyon pine and juniper has caused a major shift in species assemblages and altered fi re regime of sagebrush steppe landscapes (McIver et al. 2005). The average fi re return interval has shifted from 10–50 years, in healthy Mountain big sagebrush dominated communities, to more than 50 years (Miller et al. 1999, Miller and Tausch 2001). When fi re does burn in these woodlands it is characterized by extreme fi re behavior and results in more stand replacing fi re than in historic sagebrush communities. Native species recover slowly following high intensity fi res, allowing further invasion of exotics over large areas. This is the major concern in the Sagebrush/Pinyon-Juniper, Sagebrush/Utah Juniper, and Sagebrush/Western Juniper locations (Figure 1). These will be referred to as the ‘woodland sites’ for the rest of the Guide. The ‘Guide for Quantifying Fuels in the Sagebrush Steppe and Juniper Woodlands of the Great Basin’ was created using pretreatment data collected by fi ve fi eld crews in 2006 and 2007. The SageSTEP network consists of fi ve regional networks with 21 total sites spanning Washington, Oregon, California, Idaho, Nevada and Utah (Figure 1). Each site was a replicated, standalone experiment, however because there was a common sampling design, data were aggregated for regional representation. Why is the Guide needed? The Fuels Guide is the only SageSTEP publication summarizing the pretreatment vegetation and fuels data across 18 sites and all 5 regions into a usable tool for managers and other land stewards. Modeled after the Natural Fuels Photo Series (Ottmar et al. 2000), it allows users to quickly access percent cover, stem density and fuel loadings by fuel stratum (Ottmar et al. 2007). This information is often time-consuming and expensive to collect on a fi eld site. The Fuels Guide increases the effi ciency by giving users pictures coupled with data to make predictions based on ocular estimates and/or limited fi eld sampling. Fuels information gathered from this Guide may be used as inputs for fi re behavior and effects modeling, creating custom fuelbeds, and for a range of other applications, including describing baseline and/or target conditions for restoration projects.