Fire management

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Fire has been a natural part of the African landscape for millennia. Despite this, its use as a management tool has been controversial. For many years, fire was considered a destructive force and rangeland managers did their best to exclude it. However, over the past three decades there has been a realisation that fire is important for the maintenance of healthy savannahs, and its use as a management tool has become more widespread.

In 1996, a study on the effect of season and type of fire on mopane woodland was conducted at Malilangwe. Since then, fire has been used to:

  • Maintain a flow of quality forage to support the herbivore populations
  • Retard the growth of encroaching woody plants
  • Maintain or enhance vegetation heterogeneity, and
  • Reduce the risk of accidental or arson fires that may threaten the survival of important plant species or vegetation communities

Between 1996 and 2009, during a period of above-average rainfall, fires of medium intensity were used to remove moribund grass and promote growth of more palatable forage. This was followed by a dry spell between 2010 and 2015, when grass was in short supply and burning was infrequent. The near absence of fire over this period allowed shrubs to invade open areas, reducing grass production and visibility. This triggered a change in fire management. Hot fires, purposely designed to aggressively knock back shrubs, became the order of the day. To achieve the required outcome, fires were conducted as head burns on hot days (preferably ambient temperatures of more than 35°C) in the late dry season.

We recognised that burning had to be maximised during wet periods to compensate for the lack of fire in dry periods. Also, because grass production is depressed for up to two years after a fire, we realised that care had to be taken not to burn too frequently (every four years is optimal) or too extensively.

Our team has learned that it’s important not to burn too small an area because concentrated grazing on the limited amount of fresh growth can damage the grass layer. Certain vegetation types are sensitive to fire, and these are either excluded from management burns or only subjected to cool fires.