The results will come later. The priority for foresters, a few days after the violent fires which ravaged more than 20,000 hectares of forests in Gironde, is to save the wood affected by the flames as quickly as possible. These resources, which can still be exploited for a few days, can help limit their losses.
“We must recover everything that can be done in a short time to avoid the accumulation of insect pests such as bark beetles, explains Éric Constantin, New-Aquitaine regional delegate of the National Forestry Office (ONF). If they settle, it can damage healthy trees”.
2 million cubic meters of wood
In July, more than 7,000 hectares of forests burned in Gironde, in La Teste-de-Buch near the Arcachon basin, and nearly 14,000 hectares in Landiras, in a monoculture of pines. The Gironde timber industry fears a significant economic impact from the fires. Nicolas Douzain, general delegate of the National Federation of Wood, estimates that “two million cubic meters of wood are concerned”, a volume equivalent to “40% of what is transformed annually in the Landes basin”.
In order to save their industry, Girondin foresters have “started a race against time, says Éric Constantin. We need to be able to diagnose and harvest as much wood as possible – injured and dead – and make it usable. »
Pallets and charcoal
Quickly harvested, the wood that has burned remains usable, explains the ONF on its site. Impacts and superficial traces of fire can however lead to a downgrading of possible uses.
The least affected wood can be intended for lumber, the first level of use for construction or furniture, “but in the lower quality, that is to say pallet wood”, explains Yves Rigole, wood sales manager at the Midi-Méditerranée regional office of the ONF. In Gironde, it is the maritime pine, a forest species adapted to sandy soil, which is exploited for the manufacture of pallets “like 70% of Aquitaine wood”, underlines Nicolas Douzain.
The lumber is taken from the bole, the largest and best shaped part of the trunk located between the ground and the first large branch. Small dimension wood is called industrial wood. It is used for the manufacture of particle board, paper and cardboard or for green chemistry.
Energy, the ultimate outlet
However, the uses begin to be degressive if the fire is more heavy and aggressive. For example, wood “not calcined, but licked by the flames can in no way be used in papermaking wood” because of the presence of black bark which “pollutes the cooking of paper pulp”, underlines Yves Rigole .
If the damage is too great, wood energy remains the ultimate outlet: according to the wood sales manager at the ONF, the most affected wood is exploited in the form of “charcoal and biomass” to produce mainly heat and electricity. ‘electricity.