Biotic controls on Holocene fire frequency in a temperate mountain forest, Czech Republic

Abstract

ABSTRACTMountain spruce–beech–fir mixed forests are an important type of vegetation at higher elevations in temperate Europe. We aimed to determine how fire disturbances have affected long‐term vegetation dynamics and to assess their contribution to soil formation. We detected fire episodes using a soil charcoal record extensively dated based on14C and combined with pollen and macrocharcoal records from a local peat bog. Altitudinal shifts of the timberline during the Younger Dryas–Holocene transition seem to be responsible for an abrupt occurrence of fire at 11 200 cal a BP. The minimum fire frequency estimation based on dated soil charcoal particles showed variation during the early to mid‐Holocene in response to climatic changes. A marked decrease of fire frequency since 6200 cal a BP is attributed to the transformation of vegetation fromPicea abies‐dominated forests into mixedFagus sylvatica–Abies albastands. OnceFagus sylvaticaestablished a dense canopy a profound alteration of the disturbance regime occurred, leading to the exclusion of fire, and has indirectly accelerated the process of podzolization. Thus, the synergistic effects of biotic change are capable of amplifying a climatic impulse, illustrating the important influence of bottom‐up controls on fire regimes and soil development.