Journal Article

Determining reference conditions for ecosystem management of southwestern ponderosa pine forests

Fule, P.Z. (Northern Arizona University, Flagstaff.), Moore, M.M, Covington, W.W

1997

Overview

The fire disturbance regime and forest structure prior to Euro-American settlement (AD 1883) of a southwestern ponderosa pine (Pinus ponderosa) landscape were quantified in order to establish reference conditions as a baseline for ecosystem management. The mean presettlement fire interval between 1637 and 1883 was 3.7 yr for all fires and 6.5 yr for widespread fires, but fire has been excluded from the study area since 1883. Forest density increased under fire exclusion from an average of 148 trees/ha in 1883 (65 pines, 80 oaks, three other species), an open forest dominated by relatively large ponderosa pines, to 1265 trees/ha in 1994/1995 (720 pines, 471 oaks, 74 others), a dense forest characterized by relatively small and young trees. Species composition has shifted toward greater dominance by Gambel oak (Quercus gambelii) and conifers less adapted to frequent fires: white fir (Abies concolor) and Douglas-fir (Pseudotsuga menziesii). The reference presettlement conditions can be applied to management of this ecosystem in two ways. First, reference conditions are a benchmark against which to evaluate contemporary conditions and future alternatives. The comparison shows that the contemporary forest is well above the range of presettlement variability in forest density, and both live and dead fuel structures have developed that can support high-intensity wildfire. Second, reference conditions can serve as a goal for ecological restoration treatments.

• Publisher: Ecological Society of America
• Subject: ARBOLES FORESTALES / ARBRE FORESTIER / ARIZONA / BOSQUE DE CONIFERAS / CAUSAS DEL INCENDIO / CAUSE D'INCENDIE / CONIFEROUS FORESTS / ECOLOGIA DEL FUEGO / ECOLOGIA FORESTAL / ecological restoration / ECOLOGIE DU FEU / ECOLOGIE FORESTIERE / Ecosystem management / FIRE CAUSES / FIRE ECOLOGY / fire regime / Fire scars / FOREST ECOLOGY / Forest ecosystems / Forest fires / Forest service / FOREST TREES / FORET RESINEUSE / Old growth forests / PINUS PONDEROSA / ponderosa pine / presettlement forest reference conditions / Tree stumps / Trees