Fuel and stand conditions in an isolated, unmanaged forest landscape in central Oregon

Abstract

Abstract• Mature, unmanaged forests in western North America provide important reference conditions for managers, yet little is known about fuel composition and the factors that influence fuel accumulation in such stands. Our objectives were to characterize fuels in a passively managed landscape of dry forests in central Oregon and identify environmental factors influencing fuel accumulation.• Ordination techniques and analysis of variance revealed no statistical differences in total fuel loads across a wide range of environmental conditions.• Individual fuel size classes, however, did vary by stand location and composition. Interior stands had more 1-to 100-h fuels and snags than stands at or near the edge, stands dominated by ponderosa pine had fewer small-diameter fuels and snags, lodgepole pine stands had more 1-h fuels and snags, and white fir stands had more 10-h fuels, duff, and snag basal area.• Tree species, density and age, and years since last fire were the most important environmental variables, explaining 23% of the variation in fuels.• Our results present further evidence that fuel composition is highly variable at many spatial and temporal scales. They also provide useful baseline information for managers of fire-prone western forests.

Patterns of fuel types and crown fire potential in Pinus halepensis forests in the Western Mediterranean Basin

“…Forest structures and the type of fire they can burn changes slowly through time in the absence of disturbances. It changes suddenly and strongly due to disturbances such as wildfires or thinning (Fulé et al, 2004;Schoennagel et al, 2004;Stanton and Arabas, 2009). A wildfire is the disturbance that causes the strongest changes on vegetation in the short term (Trabaud, 1994;Whelan 1995), conditioning forest structures, fire behavior and fire types for the future (Bekker and Taylor, 2010).…”

“…These forest structures and potential fire types can also change over time, especially under different fire regimes (Flannigan et al, 2000;Fulé et al, 2004;Ganteaume et al, 2009). Furthermore, landscape and forest structures can change if there is an absence of disturbances; and several studies have assessed stand-level changes in forest structure and fuel loads within large, variable, and undisturbed landscapes (Fulé et al, 2009;Stanton and Arabas, 2009). It's well known that disturbances such as wildfires or thinning can suddenly change forest structures and dynamics and, so, condition future fire behavior (Covington and Moore, 1994;Ottmar and Alvarado, 2004;Agee and Skinner, 2005).…”

Effects of forest management on structural features important for biodiversity in mixed-age hardwood forests in Australia's subtropics

“…To the best of our knowledge this is the first study to report on the association between regular prescribed burning and DCWD dynamics in Australian subtropical eucalypt forests. In temperate, non-eucalypt ecosystems, recent studies have indeed revealed prescribed burns to significantly influence DCWD levels as a result of changed burning intervals, prevailing weather conditions at time of burn and forest age structure (Battaglia et al, 2008;Gould et al, 2008;Stanton and Arabas, 2009).…”