Life resumes a year after the fire in the Massif des Maures

• Vegetation has adapted by giving itself the ability to regenerate after some of the catastrophic events that are fires, according to our partner The Conversation.

• However, fires are “global herbivores”: they destroy the non-buried parts of plants (foliage, branches, even the trunk for trees) but sometimes also the upper part of the roots or the stumps.

• This analysis was conducted by Romain Garrouste, researcher at the Institute of Systematics, Evolution, Biodiversity of the National Museum of Natural History.

In this photo, we see the regeneration in the crown of an arborescent heather (

) burned in the August 2021 fire at the Plaine des Maures National Nature Reserve in the Var.

Fires are “global herbivores”: they destroy the generally unburied parts of plants such as foliage and branches, even the trunk for trees, but also sometimes the upper part of the roots or the stumps.

Many plants tolerate “classic” Mediterranean fires fairly well, at low levels.

They have adapted to it physiologically (mobilization of secondary buds, water storage) and/or morphologically.

Cork oaks and certain conifers, for example, have special barks with a thickness and a constitution that protect the living parts.

​Fires that act as

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Other plants have buds positioned at the base of the plants so as to regenerate as soon as the vegetative part disappears.

Finally, many species rely on regeneration from seeds rather than vegetative regeneration.

The dissemination of seeds from the cones of conifers (such as pine cones) can be favored by the heat which causes them to burst and spread.

Germination is also favored in the upper part of the soil, especially in the availability of post-fire nutrients.

Thus, with the vegetation has adapted, possessing capacities to regenerate after some of the catastrophic events that constitute the fires.

For millennia, these fires have also served as environmental management tools: they sculpt landscapes, from clearing to "cleaning up" forests.

An "opening" of the environment often sought by planners, for pastoral practices... as well as for fire prevention, precisely.

The crown, a particular form of regeneration in the Massif des Maures

These sorts of bonsai crowns from fires bear witness to past fires and the ability of these plants to regenerate from the stump, from semi-buried buds that wake up after the fire, sometimes very quickly, in depending on the season and the humidity present in the soil.

The inside of the stump is most often burned then dug by xylophagous organisms (fungi, insects).

The growth of these plants is therefore done by these successive concentric crowns which become witnesses of past fires, often forming a bead or "lignotuber".

Years after the fires, we can thus find hidden oversized stumps of shrubs that seem modest, with a much greater age than the diameter and height of their stems would suggest.

Heathers (

), wireworts (

) but also strawberry trees (

) form these characteristic bright green crowns that mark the burnt landscape and attract wildlife, including the first insects and birds.

Our “PLANTS” file

The consequences of the Massif des Maures mega fire are still being studied.

Regeneration has started but does not allow to prejudge the direct and indirect impacts, on fauna in particular.

It will take several years to take stock of this – in addition to the effects of the fire, there are those of summer and winter droughts, due to global warming.

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This analysis was written by

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Declaration of interests

• Planet

• Video

• The Conversation

• Fire

• Fire

• Global warming

• plants

• Biodiversity