Bur oak’s thick corky bark evolved as armor against prairie fires

Evidence

Have you ever wondered why a thick crust of corky bark covers the whole tree, even to the smallest twigs? This cork is armor. Bur oaks were the shock troops sent by the invading forest to storm the prairie; fire is what they had to fight. Each April, before the new grasses had covered the prairie with unburnable greenery, fires ran at will over the land, sparing only such old oaks as had grown bark too thick to scorch. Most of these groves of scattered veterans, known to the pioneers as ‘oak openings,’ consisted of bur oaks. — Aldo Leopold, A Sand County Almanac, 111

Categorization

• ADDENDUM: A tree designed by fire history — resonates directly with the trees-as-infrastructure and disturbance-reading arguments of the trees article.
• XREF: connects to: Tree species evolved distinct reproductive adaptations to fire — Miron L. Heinselman, Fire in the Virgin Forests of the…, 44; Settler farming ended prairie fires and converted grassland to oak woodland — Aldo Leopold, A Sand County Almanac: With Other…, 116