In late August 2000, the Jasper Fire burned 33,000 ha or ~7%, of the Black Hills National Forest in South Dakota. This was the largest recorded fire in the history of the Black Hills. The Jasper Fire provides an opportunity to observe the influence of pre-fire vegetative conditions, fire size, and consumptive patterns on post-fire ecological succession. As part of a 5-year post-fire monitoring effort, researchers from the RMRS and CSU are examining fire effects and patterns of recovery in ponderosa pine and aspen stands and in montane grasslands. RWU4451 scientists Drs. Anna Schoettle and Veronique Bonnet are studying post-fire establishment of ponderosa pine in the Jasper Fire in relation to environmental conditions and competition with other vegetation -POST-FIRE ESTABLISHMENT AND REGENERATION OF PINUS PONDEROSA IN RELATION TO ENVIRONMENTAL CONDITIONS AND COMPETITIVE INTERACTIONS

Understanding how silviculture and other past management activities influenced this fire’s behavior will facilitate development of restoration guidelines to reduce the risk of large-scale catastrophic fires occurring elsewhere in the intensively managed forests of the Black Hills.
The Jasper Fire burned under a variety of vegetative, topographic, and meteorological conditions and created a mosaic of vegetative mortality in patches of varying size and extent. Twenty-seven, 48, and 25 % of the fire burned under high, moderate, and low severity conditions. We quantified direct fire effects on the overstory and the forest floor in order to characterize severity. We measured crown scorch, crown consumption, bole scorch, basal scorch and basal char on individual trees. One and two-years post fire, tree mortality increased from 1 to 18 % in low severity areas and from 22 to 35% in moderate severity areas. There were no surviving trees in areas that burned under high severity. We observed a greater proportion of the crown and bole affected by fire in high severity than in low severity. Forest floor litter depths were ~17 times greater in unburned stands than in severely burned areas. Coarse woody debris was ~3 times higher in unburned areas than in burned areas; however, the relative proportion of fine and large fuels was unchanged across burn severities.
Following fire, grass, forb, and shrub cover were reduced. Shifts in species dominance, cover, and diversity were observed. Herbaceous species diversity was similar between unburned and low severity areas and between moderate and high severity areas, suggesting that there may be a threshold of plant tolerance to fire severity. By the end of the first post-fire growing season, species diversity in burned areas had almost returned to pre-burn levels. Two years post-fire, ponderosa pine regeneration densities in low and moderate severity areas were 11-20 times greater than densities observed in high severity areas.

Per our agreement with the Black Hills National Forest, we are assessing 1) the influence of forest structure and topography on fire severity; 2) fire effects on trees, understory vegetation, microclimates and soils; and 3) recovery processes, in particular, the contribution of natural tree regeneration, the soil seed bank, and resprouting individuals to vegetative recovery. Insect activity and tree disease are of primary concern, and exotic and noxious weed populations are being closely monitored. During the summers of 2003 and 2004, we will continue to monitor the indirect effects of fire on vegetation and soil, document natural vegetation recovery from the fire disturbance, and assess the effectiveness of short-term management efforts to mitigate fire effects.

Seed trap collections were made by Kirsten Smith.

Shannon McSweeney assessed fire scorch and char on trees in severely burned areas.

Tricia Balluff identified herbaceous species and cover within the understory of ponderosa pine stands.

Tricia Balluff assessed the amount of sunlight reaching the forest floor in moderately burned stands of ponderosa pine.