Canadian Forest Service Publications
Recurring surface fires cause soil degradation of forest land: A simulation experiment with the EFIMOD model. 2018. Nadporozhskaya, M.A.; Chertov, O.G.; Bykhovets, S.S.; Shaw, C.H.; Maksimova, E.Y.; Abakumov, E.V. Land Degredation and Development 29(7):2222-2232.
Year: 2018
Issued by: Northern Forestry Centre
Catalog ID: 39194
Language: English
Availability: PDF (request by e-mail)
Available from the Journal's Web site. †
DOI: 10.1002/ldr.3021
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Abstract
Renewal of pine forests is ecologically dependent on fires, but if fires become too frequent, they can disrupt the equilibrium and sustainability of these ecosystems. Field studies of the effects of fire are challenging because of the heterogeneity of forest ecosystems and because of the heterogeneous effect of fire on recovery of vegetation. As an alternative to complex field studies, mathematical models can be used as a tool to assess the complex dynamics of natural ecosystems as they recover after fire. The aim of this study was to apply the ecosystem model EFIMOD to analyse the effect of surface fires on soil degradation and its feedback on tree productivity in Scots pine forests on different soil types in Russia: Haplic Podzols in the Leningrad region and Psamment Entisols of the fragmented steppe in the Samara region. Simulation of the cumulative effects of fire cycles over 140 years showed that one fire did not affect growing stock but decreased soil organic matter by about 10% at both sites, and that three fires reduced the growing stock by 30% on the Haplic Podzols and 9% on the Psamment Entisols and decreased soil organic matter by about 30% on both sites. Forest fires led to the loss of soil carbon (C), as well as nitrogen (N), which is a principal limiting factor in forest ecosystems of boreal and temperate ecozones. The effect of repeated fire cycles on land degradation is similar to that of soil erosion, through the loss of soil C and N.
Plain Language Summary
In recent decades the frequency and area of forest fires is increasing in Russia and Canada. If fires occur too frequently they can change the balance between how fast trees grow and the ability of soil to provide nutrients for tree growth. This in turn can affect how the forest takes up greenhouse gases like carbon dioxide from the atmosphere through tree growth and how the soil releases carbon dioxide to the atmosphere through decomposition. Computer models can be used to calculate the effect of repeated fires on forests over 100 or more years, something that is difficult for people to measure in the forest. We used the European Forest Institute computer model (EFIMOD) to simulate the effect of repeated fires over 140 years on Scots pine forests in Russia. In a scenario with one fire event during the simulation period, tree growth was not affected and there was a 10% loss of soil organic matter. When we simulated three fires in this period, tree growth decreased by 30% and there was a 30% loss of soil organic matter. To do a good job calculating the contribution of forests to the global greenhouse gas balance, we need to understand the effect of repeated fires on forests and their emissions of carbon.
