The view from the foothills of the Sierra Nevada in California can be beautiful—pine forests and chaparral spill across an often rugged landscape. But as more people build homes in this area, where development gets into wild land, they’re facing some of the highest risks for wildfires in the country.

The type of trees, plants and grasses at any location will influence how likely the area is to burn. However, our new research shows that some areas of the wildland-urban interface—the land where development ends and wilderness begins—are at much higher risk of burning than others. A key reason is how vulnerable the local vegetation is to drying out in a warming climate.

在一个study published on Feb. 7，我们的气候科学家，消防科学家和生态水文学团队映射了植被在美国西部造成最高的火灾风险的地方，我们将该地图与该地区人民进入野外城市界面的地图。

We were surprised to discover that the fastest rate of population growth by far has been in the areas with the highest fire risk. This includes several areas in California, Oregon, Washington and Texas.

Plant sensitivity has a large effect on fires

When a fire does break out, the amount of area that burns increases significantly if a region’s vegetation is drought sensitive, meaning it dries up easily after periods of little rainfall and hot temperatures.

Just as a succulent is better at surviving a water shortage than, say, a citrus tree, some vegetation loses moisture more quickly in dry conditions. Such diverse sensitivity can have a strong effect on wildfires. In fact, we found that under the same increase in droughtlike conditions, burned area increases twice as much in the most sensitive regions as the least sensitive regions. As a result, fire hazard in regions like California, eastern Oregon, and central Arizona has far outstripped the average. But what about human exposure to wildfires?

（有关建设野火区的详细信息，请参阅this articleby Joseph Lstiburek of the Building Science Corp.)

The wildland-urban interface population boom

我们发现，虽然生活在野外城市界面的人数总体上从1990年到2010年的总体大致翻了一番，但其最高危险地区的人口增长了160％。随着越来越多的人进入这些领域，机会触发点燃升起那as does the number of people at risk.

总体而言，这些高危险地区的人口从1990年的100万增加到2010年的26​​0万，最近一年是详细的人口数据。这增加了与当前旧金山和西雅图合并的人口相同。

更多人仍然生活在野蛮城市界面的低危险区域，人口从1990年的500万增加到2010年的10.4百万，但高危险地区的增长更快。

我们不知道在美国西部这些高度敏感地区造成人口繁荣是什么。建筑规范那木材依赖社区和寻求森林包围的家庭的人可能有助于威胁城市界面的扩展，但仅那些因素不解释为什么人口将在最脆弱的地区中崛起。

然而,地图的植被对水分的敏感性r shortages can provide some insight. By linking基于卫星植被干燥的估计to climate observations, we created continental-scale maps of vegetation moisture. For the first time, we now know the precise locations of the most drought-vulnerable and hence fire-prone vegetation.

The map shows that the foothills of the Sierra Nevada in Central California, the outskirts of the San Francisco Bay Area, San Diego and San Antonio all have drought-sensitive vegetation and saw populations expand in the wildland-urban interface.

进一步研究人口和疯狂的al land use and development regulations in such regions can shed light on the drivers of growth in these high-risk areas. In the Bay Area, for example, a lack of affordable housing has pushed peoplefarther from citiesand may be encouraging more development in the wildland-urban interface, including high-risk areas that hadn’t previously been developed.

人们生活在高风险地区有什么呢？

高危险地区的不成比例的人口增长是警告，人类在高风险植被的区域中引发火灾的可能性正在上升 - 并且它可能会高于先前理解的。

社区领导人可以使用这些知识来确定人类活动与干旱敏感区域重叠的地方，以改善当地的土地利用规划，制定消防资源并开发更安全的疏散路线。

Property owners can keep asafe defensible space在家庭的各个方面至少有100英尺的非终端土地，以帮助保护它们的结构在野火发生时。Retrofitting使用防火材料或双窗帘的家园也可以帮助。

Preventive measures like these can limit the来自野火的气球损失那includingdevastating air quality due to wildfire smoke，同时也让人类与自然火灾更安全地共存。

Preparing homes for wildfires can take months, so it’s important to use the winter, when many of these areas have their wet seasons, to be ready by the time the land dries out and wildfires ramp up in spring.