How do humans affect forest fires? And what can we learn from forest fires in the past for the future of forestry? An international team of researchers led by Elisabeth Dietze, formerly at the German Research Centre for Geosciences GFZ in Potsdam and now at the Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research, now provides new answers to these questions. The research team has shown for a region in north-eastern Poland that forest fires increasingly occurred there after the end of the 18th century with the change to organised forestry. Among other things, the conversion of forests into pine monocultures played a role. The increased number of fires subsequently made it necessary to manage and maintain the forests differently. The researchers report on this in the journal PLOS ONE.
Every natural landscape has its own pattern of how fires behave there. This pattern is also known as the "fire regime". Fire regimes are directly linked to the landscape, its vegetation and climate. Humans can change these regimes by managing a landscape. However, little is yet known about how they influenced fire regimes before the beginning of active forest fire fighting. Among the past 250 years, the human contribution to the global increase in fires during the mid- 19th century is particularly unclear, as the data available for this period is not comprehensive.
In the study published now, the researchers examined the extent to which forest management influenced the fire regime in a temperate forest landscape around Lake Czechowskie in the Bory Tucholskie (English: Tuchola Forest). Bory Tucholskie located in north-eastern Poland is one of the largest forest areas of Central Europe. The researchers combined evidence from various sources, such as pieces of charcoal and molecules formed during biomass combustion, so-called molecular fire markers. The investigated material originated from drilling cores of lake sediments. The researchers applied a new statistical approach to the classification of fires to their samples. They compared their measurements with independent climate and vegetation reconstructions and historical records.
The complete GFZ press release is available online.
Original study: Dietze, E., Brykała, D., Schreuder L.T. et al., 2019. Human-induced fire regime shifts during 19th century industrialization: a robust fire regime reconstruction using northern Polish lake sediments. PLOS ONE. DOI: 10.1371/journal.pone.0222011