A mixture of human and climatic effects shapes the 250-year long fire history of a semi-natural pine dominated landscape of Northern Latvia

Fire has been shown to shape successional pathways and dynamics of forest vegetation. However, its role in European hemiboreal forests remains poorly understood. Here we provide the first annually resolved reconstruction of fire history from the Eastern Baltic Sea region, developed in the pine-dominated landscape of Slitere National Park (SNP), northwestern Latvia, over the last 250 years. Our results suggest that forest fires have been a common disturbance factor in the studied landscape. In total, we dated 62 single fire years, with the mean-point scale fire return interval of 46 years and the length of the fire cycle ranging from 45 to 80 years. We identified periods of high (1750-1950) and low (1960-2000) fire activity, with the corresponding lengths of fire cycles being 45-68 and 58-80 years, respectively. Although both long-term (century and decade-long) and annual dynamics of fire activity in SNP was closely linked to socio-political changes in Latvia, fire activity in SNP was also affected by climate, as indicated by the close positive association of years with increased area burned and positive SST anomalies in the Baltic and North Seas. Future management of SNP should make fire an important element of natural forest dynamics and consider using prescribed fires of various spatial extent and severity.