Changes in fire frequency and timing can transform vegetation
Fire is a natural part of all ecosystems.
Wildfires have been burning vegetation and shaping landscapes far longer than people have been on Earth. However, changes in patterns of fire can result in degradation if the vegetation is not adapted to the new fire regimes. In this context it is possible to have both too much, and too little, fire in a landscape.
Patterns of fire vary across the globe: boreal forests burn infrequently (every few hundred years) but when they burn, fires are intense – consuming entire forests with flame heights of 20 m and more. Grassland ecosystems may burn every few years, but these fires are less intense, and seldom damage mature trees.
Organisms are adapted to the particular fire regime that they evolved under, but patterns of fire can quickly change with changing climates, human activities (ignition/suppression) and land cover. Two key factors that people change with fire is the frequency (or “return period”), and the season or time of year that fires occur. As fire frequency and season change, they can also affect fire intensity, with important implications for plants, animals, and people living in these regions, potentially causing long-term damage to land biomass components affecting soil structure, nutrients and water cycling.