The first forest fire history of the Burabai Region (Kazakhstan) from tree rings of Pinus sylvestris

Abstract

Forest fires are one of the most important events causing an abrupt decrease in tree-ring width. Although humans are the main cause of forest fires, extreme weather or climate change may promote the frequency and severity of fires. The purpose of this study is to reconstruct historical fires in the Burabai Region of Kazakhstan including their frequency and seasons. Five tree cross-sections with fire scars were collected from two different sites, Akylbai and Burabai. After sanding the transversal surfaces of the cross-sections, the year and season of fire scars were determined. We identified 15 fires during the last 300 years in the region. The mean fire interval is 27 years, with minimum and maximum fire intervals of 9 and 53 years, respectively. The seasonally determined fire scars generally occurred during the middle earlywood formation (77%), and less in early earlywood (22%). Three site chronologies of Pinus sylvestris L. were also used to find the effect and extent of the fires. The negative effect of fires on tree growth lasted 1 to 8 years after the fire. Four of the fire scars had long-term negative effects (up to 10 years) on tree growth in the years of 1759, 1779, 1871, and 1952. Fires of 1759, 1797, 1824, 1833, 1852, and 1871 are seen in both sites, suggesting that these fires spread over large areas.