Conifer Regeneration after Forest Fire in the Klamath-Siskiyous: How Much, How Soon?

摘要: regime and have led to changes in forest structural characteristics (Agee 1993, Sensenig 2002). High-severity, stand-replacing fires also been known this region, where complex topography fire behavior typically resulted a patchy distribution of canopy openings, intact stands, scattered surviving trees (Wills Stuart 1994, Alexander et al. 2006). The prognosis recovery after high-severity is uncertain. A history regeneration failures logging raised concerns over the long-term sustainability conifer forests region (Hobbs 1992). Large brushfields dominated extensive areas southwest Oregon mid-20th century may from set by early settlers, ranchers, miners (Hayes 1959). Limited long periods (10–50 years) fostered that such would remain unforested indefinitely (Gratkowski 1961). Additional occurred clearcut harvesting, attempts improve environment through shelterwood cutting had mixed results (Stein 1986). Given uncertainty, questions arose as whether conifers regenerate recent times. Fears emerged common Klamath-Siskiyous highland 1900s 1959, Gratowski 1961) become dominate feature 21st well (Sessions 2004). Of particular concern was competitive advantage broad-leaved shrubs hardwoods result removal overstory fire. Hardwoods, particularly tanoak (Lithocarpus densiflora), madrone (Arbutus menziesii), oaks (Quercus spp.), resprout vigorously (Brown Smith 2000). rapid growth seed-bank species Ceanothus their association with nitrogen-fixing bacteria can lead shrub cover successional communities (Hanson 2005). Without active reforestation, little or no window for amid rapidly growing 1992, Sessions Along competition moisture space, high levels seed predation surface soil temperatures mortality rates within 1st year (Minore Laacke [1992] references therein). Extensive research has documented planting controlling increase tree density years stand development Zhang Today, many postfire action plans regard treeplanting vegetation control relatively straightforward effective solution problem renewal (Lindenmayer Little about how burned will recover on own, they might differ stands managed fire, these differences relate rate short term (1–2 longer decades) time frames. lack information concerning ecosystem recovery, specifically natural wildfires, allowed speculation ecological processes. For example, 2-year study survival without salvage Oregon, Donato (2006) concluded management activities 2 killed most be counterproductive recovery. This conclusion contradicted recommendations policy analysis which argued develop into unproductive fields persist “decades, perhaps centuries” speed provide revenue timber extraction We report here abundance regenerating occupying sites 9–19 wildfires northern California Oregon. Our findings redefine concepts role reliability frequency systems context (Christensen 1996). Additionally, highlight temporal spatial variation an inherent development. Forest managers relying should feel increased confidence need accommodate accept prolonged line process.