Riparian Plants: Fremont Cottonwood - Populus fremontii
Fremont cottonwoods dominate the riparian forests of the Central Valley. They require access to the water table, which their roots can reach to a depth of seven meters. Cottonwoods can tolerate both long duration flooding and can survive drought, often through trunk re-sprouting after the top of the plant dies. Cottonwoods are common at low to moderate depths to the water table and they are replaced at high flooding disturbances by sandbar willow and at moderate flooding disturbances by Goodding’s willow. Cottonwoods grow best in coarser grained (sand) to loam soils. Seedling germination and establishment are closely adapted to the timing of high flows, and requires bare sand or gravel with adequate moisture.
Fremont Cottonwoods are tall (12-35m) single trunked trees. Their trunks can be up to 1.5m wide, and begin with smooth bark that becomes deeply furrowed with age. These tall, narrow trees branch near the top of the tree and lead to multiple small stems. Many migratory birds nest in the tall trees, and cottonwood snags are commonly used by cavity nesters. Raptors that hunt near water will also use the tall trees to build their nests. Like sycamores valley oaks, cottonwoods are often used for heron and egret rookeries. Cottonwoods are important foraging habitat for Yellow-billed cuckoos.
For more information about the ecological tolerances and structure of riparian plants, see Gaines 1977, Conard and others 1977, Holstein 1984, Sacchi and Price 1988, Faber and Holland 1996, Cooper and others 1999, Vaghti 2003, Fremier and Talley 2009, and Vaghti and others 2009.
Fremont Cottonwood dimensions
Cottonwood in open
12 year cottonwood in winter