Late-Holocene response of limber pine (Pinus flexilis) forests to fire disturbance in the Pine Forest Range, Nevada, USA

Despite growing concerns that ecological stressors (fire, insect and pathogen outbreaks) may force vegetation change, few studies have attempted to use paleoecological data to understand small-scale interactions between disturbance and vegetation. Using charcoal and pollen data, we infer past fire episodes and subsequent vegetation responses for a limber pine (Pinus flexilis) forest in northwestern Nevada, USA, to determine local vegetation recovery from disturbance. Using superimposed epoch analysis we examined average-vegetation and individual-taxon responses to eight randomly selected fire events over the past 4.0 ka. Pollen evidence shows that on average fires produce a weak response of declining Pinus while other taxa including Artemisia and Poaceae increase directly after fire episodes. Within 30 yr of a disturbance, pollen data indicate ecosystem recovery to pre-fire composition, consistent with modern studies of fire recovery of limber pine forests. Similar to short-term changes of pollen abundance, long-term vegetation responses indicate Pinus abundance weakly declining and Artemisia increasing when fire episodes are frequent. However, despite fire-episode frequencies varying between 75 and 250 yr, the overall vegetation structure has remained relatively stable over the past 4.0 ka. Our study contributes to the limited information on the disturbance ecology of isolated, subalpine forests in the intermountain West.