The Sala fire in the Västmanland County of central Sweden that burned about 14,000 ha in 2014 has been the largest fire recorded in the modern history of Sweden. To understand the long-term fire history of this area, we dendrochronologically dated fire scars on Scots pine (Pinus sylvestris L.) trees (live and deadwood) to reconstruct the fire cycle and fire occurrence in the area affected by the 2014 fire. We identified 64 fire years, using a total of 378 pine samples. The earliest reconstructed fire dated back to 1113 AD. The spatial reconstruction extended over the period of 1480–2018 AD. Lower levels of fire activity (fire cycle, FC = 43 years, with the central 90% of the distribution limited by 35 to 57 years) dominated in the earlier period (1480–1690 AD) that was followed by a strong decrease in fire activity since 1700 (FC = 403 years, with 90% of the distribution being within 149 to 7308 years), with a fire-free period between 1756 and 2014. Sala area, therefore, features the earliest known onset of fire suppression in Scandinavia. The high demand for timber during the peak in mining activities in the study area around the 1700–1800s, accompanied by passive fire suppression policies, were possibly the main drivers of the decline in fire activity. Superposed epoch analysis (SEA) did not show significant departures in the drought proxy during the ten years with the largest area burned between 1480 and1690. It is unclear whether the result is due to the relatively small area sampled or an indication that human controls of fires dominated during that period. However, significant departures during the following period with low fire activity (1700–1756), which just preceded the last fire-free period, suggested that the climate became an increasingly important driver of fire during the onset of the suppression period. We speculate that the lack of major firebreaks, the homogenization of forests, and the lack of burned areas with low fuel loads might contribute to the occurrence of the exceptionally large 2014 fire in Sala.

瑞典中部韦斯特曼兰县的萨拉大火于2014年燃烧约14,000公顷，是瑞典近代史上最大的大火。为了了解该地区的长期火灾历史，我们按照时间顺序对苏格兰松树（Pinus sylvestrisL.）树木（活木和枯木）来重建受2014年大火影响的区域的火灾循环和火灾发生。我们使用总共378棵松树样品鉴定了64个火年。最早的重建大火可以追溯到公元1113年。空间重建在公元1480年至2018年期间进行。在较早的时期（公元1480年至1690年），较低水平的火灾活动（火灾周期，FC = 43年，分布的中心90％受35至57年的限制）占主导地位，随后火灾活动急剧下降自1700年以来（FC = 403年，分布的90％在149至7308年之间），无火期在1756年至2014年之间。因此，萨拉地区是斯堪的纳维亚半岛最早已知的灭火方式。在研究区域1700-1800年代采矿活动高峰期间对木材的高需求，加上消极的灭火政策，可能是造成火灾活动减少的主要原因。叠加纪元分析（SEA）在十年期间没有显示干旱代理的明显偏离，最大的面积在1480年至1690年之间。目前尚不清楚结果是由于采样面积相对较小还是表明在此期间人类控制了火灾。但是，在随后的一段时期内，由于火灾少（1700年至1756年）而发生了重大变化，恰好在最后一个无火时期之前，这表明在抑制期开始之际，气候已成为越来越重要的火灾驱动因素。我们推测缺少主要的防火措施，