A palaeoecological attempt to classify fire sensitivity of trees in the southern Alps

Using pollen percentages and charcoal influx to reconstruct the Holocene ve getation and fire history, we differentiate six possible responses of plant s to fire of medium and high frequency: fire-intolerant, fire-damaged, fire -sensitive, fire-indifferent, fire-enhanced and fire-adapted. The fire sens itivity of 17 pollen types, representing 20 woody species in the southern A lps, is validated by comparison with today's ecological studies of plant ch ronosequences. A surprising coincidence of species reaction to fire of medi um frequency is characteristic for completely different vegetation types, s uch as woodlands dominated by Abies alba (7000 years ago) and Castanea sati va (today). The temporal persistence of post-fire behaviour of plant taxa u p to thousands of years suggests a generally valid species-related fire sen sitivity that may be influenced only in part by changing external condition s. A non-analogous behaviour of woody taxa after fire is documented for hig h fire frequencies. Divergent behaviour patterns of plant taxa in response to medium and high fire frequencies (e.g., increases and decreases of Alnus glutinosa) also indicate that post-fire plant reactions may change with in creasing fire frequency.