Fire history and ecology of the boreal forest nature reserve Trillemarka-Rollagsfjell

Abstract

ABSTRACT Macroscopic charcoal particles (axis ≥ 0.5mm) give an indication of local fire presence to a fine spatial accuracy. I have examined the history, distribution and impact of fires on the ecology of Trillemarka-Rollagsfjell boreal forest nature reserve, located in the south of Norway. Data were obtained from a total of 225 soil core samples from 15 macro sample plots measuring 300 x 300m2. There was macroscopic charcoal in 153 of the soil samples out of 225, giving an estimated burned area of 68%. The average mass of macroscopic charcoal was 32.43 gm-2 (324.3 kg ha-1). The mass of macroscopic charcoal correlated with the component of dead trees in the macro sample plots as well as the combination of the proportion of Scots pine and the dead trees components (p-value ≤ 0.05 > 0.036; and p-value ≤ 0.05 > 0.028). However there was no correlation between the mass of macroscopic charcoal and Norway spruce, birch, aspen and rowan which formed the other components of the forest. There were large variations in macroscopic charcoal mass between macro sample plots and within macro sample plots. These variations are consistent with findings from Norway and many other boreal forest zones. Variations result from the mosaic pattern of fire occurrence and spread through the boreal forest landscape. This fire pattern is influenced by climatic factors, vegetation composition and terrain conditions like rate of accumulation of suitable fuel load. Overall, the results of this study indicate a moderate fire impact within Trillemarka-Rollagsfjell nature reserve which may not be as important presently as it were few centuries ago.