Maples Acer

Acer is a genus in the Sapindaceae family, grown as trees and shrubs, ranging from about 10 to 100 feet tall among the 22 species measured. Of the 29 species assessed, 24 come back fire resistant, four are assessed with no side taken either way, and one, sycamore maple, is rated keep away.

The most-studied member of the genus, red maple, carries that fire-resistant rating, along with sugar maple and boxelder. Red maple can grow multiple stems with ladder potential in a naturalized setting, increasing flammability. Sugar maple's assessment flags susceptibility to road deicing salts and drought intolerance. Boxelder's assessment gives the reasoning directly: fire-resistant plants tend to resist ignition when irrigated and maintained, while fire-prone plants can ignite readily and burn intensely.

Sycamore maple, Acer pseudoplatanus, is the keep-away exception, carrying a substantial body of assessment, the name to watch on a plant label. A few themes recur across the assessments without extending to the whole genus: maintenance and irrigation in seven members, invasiveness in four. A Forest Service review of bigleaf maple found it thin-barked and not fire-resistant, though thick-barked mature trees can survive a moderate-severity fire, a finding about that species' bark, not the genus.

Maples grow natively across the north-central, southeastern, northeastern and south-central United States, with hardiness spanning USDA zones 2a to 6a among the six species zoned. Other members of the genus, including Florida maple, trident maple, hedge maple, vine maple, southern sugar maple and tatarian maple, are named only, with no rating attached. Near a house, the name on the tag matters: sycamore maple is rated keep away, and most of the genus is not.