Restoration after a forest fire

After a sad record summer in which more than 200,000 ha of forest surface have been burned due to fires, the question arises as to whether or not it is appropriate to act on the now desolate surfaces and in what way.

Some Autonomous Communities deal legislatively with the actions to be carried out after a forest fire, as is the case of Andalusia with Law 5/1999, of 29 June, on the Prevention and Fight against Forest Fires, in its article 51, establishes that the owners of forest land will draw up a Restoration Plan after which the competent Council for forestry will decide, who will indicate the actions to be carried out, the rules of use and exploitation that will be applied, the actions and deadlines for their execution.

Traditionally, Restoration Plans used to include the reforestation of some or all of the affected land, but currently the trend has changed.

The first actions to be carried out after a fire are aimed at preventing the loss of soil, a bare ground that could be washed away by wind, erosion, and landslides simply caused by precipitation. For this purpose, on sloping land, wooden palisades obtained from the fire itself, fajinas and albarradas are usually carried out, works aimed at reducing the speed of water on the slopes and preventing the formation of gullies. Another way to reduce erosion is the application of mulch made of straw or other plant debris by hand or with a helicopter (helimulching), a method capable of reducing soil loss by up to 95%.

Avoiding soil movement is also important to avoid carrying away the seeds it contains, some of which have been deposited there thanks to the temperatures reached by the fire itself and the ability of some species to adapt to the recurrence of fires.

Species such as Pinus halepensis or Pino Carrasco have adapted to the recurrence of fires with a strategy that allows them to colonize more quickly than other species. It is able to keep its pineapples on the branches of the tree, closed for years (called serotine pineapples), fertile and waiting for a situation of high temperatures (+50ºC) to be able to open and release their seeds, who will also benefit from a soil rich in ash and without any competition after the passage of a fire.

Another example of species that have also adapted to the recurrence of fires is Genista scorpius or Aliaga, who stores their seeds at their feet for years waiting for a fire to burn their dry branches, which usually burn virulently and will allow the seed to open and be ready for germination.

These two are clear examples of germinating pyrophytic species, resistant to fire thanks to their ability to germinate after the passage of it.

In addition to this seed bank that we will find in the ground after the passage of a fire, we must also take into account the so-called resprouting pyrophytic species, those that are capable of being burned in their entirety aerial (above the ground), but which will keep their root system and/or some parts of their trunk alive, so they can sprout and continue to live. As examples we can cite: Quercus ilex or oak, Pistacia lentiscus the mastic, Stipa tenacissima the sputum, Juniperus oxycedrus or juniper.

Secondly, tasks aimed at sanitation of the forest are usually carried out, starting with the removal of dead wood to prevent the proliferation of xylophagous insects, those that feed on wood and could pose a problem for trees that have survived and are weakened.

And, after the actions aimed at soil support and sanitation, we would be left to focus on regeneration itself, the great dilemma: should there be reforestation? The current tendency is to avoid them and to let the forest regenerate alone, with its own seeds and sprouts, with native species that are daughters of those that already made up the mountain before the fire occurred. Repopulation actions will only be carried out in those areas that, due to the passage of machines that have worked to remove dead wood or some other problem, cannot regenerate on their own. Personal and financial efforts will be saved and can be used in that same forest for future forestry work.