She had opened the ball of the mega fires of summer. Hit in May by a fire as rare as it was violent, the forest of Rennes had been nibbled by the flames for three days. Hidden in roots and peat, the fire had engulfed 20 hectares of soil parched by weeks of no rain. Unaccustomed to fighting fires of this magnitude, Brittany was also preparing for a scorching summer punctuated by several large fires. A year after this first alert, the National Forestry Office drew up an initial assessment of its intervention. Its agents are already working on the reconstruction of the forest massif and the development of a “mosaic forest”.
Behind this poetic name hides a very simple principle: that of mixing species and staggering plantations by plot, while varying the methods of silviculture. The ONF agents intend in particular to capitalize on the devastation caused by the flames by gradually replanting “in the gaps created by the fire”. Foresters will notably be able to rely on more heat-resistant species to adapt the massif to global warming. On the 3,000 hectares of the forest of Rennes, there is a fragile balance between hardwoods (oak, beech, chestnut, birch, etc.) and softwoods (maritime pine), which share the space almost equally. But it will take time to heal the massif, which is subject to “very significant” stress and which is more easily exposed to parasites.
Waiting for the “seed rain”
For now, only the plots where the trees were the youngest have been replanted. In areas where the vegetation was older, the ONF wants to “give a chance” to the trees affected by the fire to redo the icing. By adopting this technique, the agents hope that the forest will benefit from a “seed rain” developed by the oldest vegetation which will allow natural regeneration. It will take between two and four years to get there.