A 350-year tree-ring fire record from Białowieża Primeval Forest, Poland: implications for Central European lowland fire history

1. Fires are nowadays small, yet frequent, in temperate Central European conifer forests, but little is known about the fire history in this region. This is likely due to the lack of intact forests that contain old trees and dead wood from which fire history may be reconstructed. An exception is the Białowieża Primeval Forest (BPF) in Poland for which we were able to reconstruct the fire history in detail. 2. From 886 tree ring samples collected in a 13-ha conifer-dominated area, we reconstructed fire events and tree establishment back to the mid 1600s. From 1653 to the late 1700s fires were very frequent, with mean point (single tree) fire intervals of 18 years and mean stand scale fire intervals of 6 years. After 1781, the intervals between the fires increased dramatically, and since 1874 no major fire was recorded. 3. Tree establishment underwent substantial changes, closely tracking shifts in fire frequency. When fires were frequent, Pinus sylvestris establishment occurred only sporadically. Later, less frequent fires promoted massive establishment of both P. sylvestris and Picea abies. At present, only P. abies and a few deciduous trees regenerate. 4. Synthesis. We present the first high-resolution fire history in the Central European temperate lowland forest area. The discovery of old P. sylvestris trees and stumps with fire scars in many conifer-dominated parts of BPF show that fire was a major component in the past dynamics of this forest. We also show that historically, fires were recurring at very close intervals, supporting an open, Pinus-dominated forest. These result contrasts with the written history of BPF, which focus on a few, large fires from the past. Human influence on the fire regime was probably substantial, although the disentangling of climatic and human impacts needs further studies. We propose that fire should be increasingly taken into consideration in models of disturbance, vegetation development and forest openness in the whole Central European lowland forest region.