Att läsa brandspår i skogslandskapet: olika underlag för att förstå naturlandskapets branddynamik

Abstract: The purpose of this study is to explore different methods to understand the local history of past fire disturbance regimes in a forest management unit. Focusing on the Bergslagen region in south-central Sweden, which has a very long history of forest management, the frequency of occurrence of fire scars on living trees, burned wood, and macroscopic charcoal in the litter layer and in small peat bogs, were studied in landscape strata different with different biophysical characteristics affecting the probability of fire. The prediction of the so called ASIO model was tested, that the distribution of relative fire frequencies Absent, Seldom, Intermittent and Often (in Swedish: Aldrig, Sällan, Ibland and Ofta) were related to site type, and to three landscape strata, (I) dry soil on coarse sediments, (II) glacial till on south-western and (III) north-eastern slopes, respectively. The site type distribution was clearly different among the three landscape strata and with a gradient from more to less fire fire-prone site types from coarse sediment and to south-western and north-eastern slopes. While fire-scarred trees were absent in the study area, the frequency of occurrence of signs of past fire events was highest in site types of the Often type, and declined to Intermittent and Seldom types in both soil litter and peat bogs. To conclude, this study shows that examination of biological archives can be used the stratify forest management units into different strata to guide forest management so that natural disturbance regimes are emulated where appropriate.