Should we rebuild the areas that have gone up in smoke or rather have them evacuated? This is the dilemma facing many experts after the wildfires that have devastated the American West in recent weeks, killing more than 30 people and burning thousands of buildings.
Many of the communities affected this summer were built in wooded areas, sometimes in the very heart of forests. With the effects of climate change, which accentuates drought and the risk of large-scale fires, these regions located at the meeting point between cities and forests (“habitat-forest interface” for specialists) will remain particularly vulnerable.
This is the case of the small town of Paradise, in northern California, 90% destroyed in 2018 by a fire that killed 86 people. The town had barely begun to rebuild and repopulate itself when it was again threatened by the flames of the “Bear Fire”, which ravaged the region last month.
Undesirable effect of these repeated fires: in Paradise as elsewhere, insurance premiums have skyrocketed and new contracts are often refused.
In California alone, one of the worst-hit states this summer, 6,500 buildings were destroyed in August alone. Something to think about the 50 million American households who live in this famous “habitat-forest interface”.
But for Gregory Pierce, an urban planning specialist at UCLA, many areas in this interface “are overcrowded and should never have been developed from an environmental point of view.” “It is the last resort, which neither the inhabitants nor the legislators want to arrive, but eviction will be part of the solutions,” he believes. “But for some communities, it's the only way to survive,” says Pierce.
These rural areas, where land is cheaper, have grown enormously in recent decades, particularly in California where real estate prices are among the highest in the country. Between 1990 and 2010, they exploded, both in terms of new housing (+ 41%) and area (+33%) according to statistics from the forestry office.
“These places are built near canyons with very dense vegetation, which are difficult to access,” observes Darrell Roberts, an officer in the fire department of Southern California. “Everyone wants a nice house in the shade of trees and in the middle of nature, but there are risks,” he insists.
More resistant materials
While it is difficult to counter climate change and chronic drought, some experts are betting on better management of vegetation to minimize the impact of fires.
We must of course clear around all homes, but “controlled fires” can also remove trees and dry grass that feed fires, said David Shew, a retired California firefighter.
“These practices can work very well, but they are very difficult to implement today because of the number of people who live there”, in the middle of wooded areas, he notes.
David Shew nevertheless believes that the eviction of residents in vulnerable areas is an extreme measure. A building ban similar to the one implemented in flood-prone areas in Mississippi would be difficult to enforce, he said, because fires are “very random” and difficult to predict.
Mr. Shew, who is also an architect, advocates for his part a change in the materials used to build the houses, whose structure and walls are most often wood covered with a thin siding in the western United States. .
Reinforced walls, fire-resistant roof: “today, we know that we can build with smarter and more resistant materials, at a cost that is not significantly higher than a traditional construction”, assures- he.
As for existing homes, David Shew believes that it would be in the interest of homeowners and insurance companies to invest in a renovation to make them also flame resistant.
“In the United States, it is almost a mantra to say: 'we are going to rebuild, we are not going to give up, we are going to raise our heads and come back and settle down.' But the reality “is that we will never have enough fire trucks to place one in front of every house,” he says.