Forest fires cause unexpectedly large nutrient losses
It is not just vegetation that is lost in forest fires. When a forest burns, there is also an impact on the soil, through the loss of carbon and other nutrients. This loss of nutrients can negatively affect subsequent growth and carbon storage in the ecosystem.
Now, in a major international study, researchers have analysed the effects of forest fires by putting together a global compilation of fire experiments. This concerns experiments in areas where vegetation has been protected from fires and, conversely, where fires have been frequent. Some of the experiments have a history spanning as long as 65 years. The compilation covers deciduous and coniferous forests as well as the more open landscape of savannas.
“The study shows that the losses of carbon and nitrogen in the soil in large parts of the world’s ecosystem are considerably larger than we previously thought”, says Anders Ahlström, physical geographer at Lund University’s Faculty of Science.
A surprising finding from the study was that the carbon and nitrogen losses do not diminish over time. According to the study, even after 65 years of repeated fires the losses had not decreased”, states Anders Ahlström.
“It does not appear that fires lead to new growth of vegetation that compensates for the carbon losses, as was perhaps previously assumed,” he says.
Anders Ahlström and his Lund colleague, Lars Nieradzik, participated in the international compilation project. They consider that the study provides valuable insights into how fires affect both vegetation and the storage of carbon and nutrients in the soil. Such knowledge is important, for example in efforts to predict the various effects climate change will have on nature in the future. The study has been published in the research journal, Nature.
Text: Lena Björk Blixt