Californian megatrees and fire regime
Plants are not adapted to fire per se, but to different fire regimes [1, 2]. A clear example is the Californian megatrees [3]. Sequoia sempervirens (coastal redwood; world’s tallest tree in terms of biomass) is well-adapted to high-intensity crown fires; for example, most trees survived the 2020 CZU Complex Fire (only ca. 5% mortality, [3]). In contrast, Sequoiadendron giganteum (giant sequoia; world’s most massive tree) is adapted to surface fires only. This species has difficulties supporting high-intensity fires; for example, within the 2020 SQF Sequoia Complex [SQF] Fire area, more than 40% of large sequoias were killed (similar results were observed in the 2021 KNP Complex Fire and the 2021 Windy fire) [3]. The conclusion is that recent highâseverity fires were novel events for giant sequoias, but not for coast redwoods.
Left: Sequoiadendron giganteum (giant sequoia) with a fire scar in the base from a surface fire. Right: Sequoia sempervirens (Coast redwood) resprouting epicormically after a high-intensity fire (click to improve quality).
References
[1] Keeley JE & Pausas JG 2019. Distinguishing disturbance from perturbations in fire-prone ecosystems. Int. J. Wildland Fire 28: 282-287. [doi | pdf]
[2] Keeley JE & Pausas JG 2022. Evolutionary ecology of fire. Ann. Rev. Ecol. Evol. Syst. 53: 203-225. [doi | pdf]
[3] Keeley JE & Pausas JG. 2025. Sequoia and Sequoiadendron: Two paleoendemic megatrees with markedly different adaptive responses to recent high-severity fires. Am. J. Bot. 112: e70089 [doi | pdf]