BOTANY OF LA BREA
The Californian floral province of the last ice age thrived in a more humid climate than what we experience today.
Explore each plant community to learn more about their flora.
PLANT COMMUNITIES
Closed-Cone Conifer Forest
Closed-cone conifer forest or woodland has a canopy dominated by a single species of conifer, typically pine or cypress. Due to the short-lived nature of pines, many dead and fallen trees litter the understory and provide organic material and habitat. These forests avoid drying out by capturing sea fog which drips into the understory, thus droughts are often avoided. Among the flora from this plant community you would not see in the hills today are the Monterey pine and Monterey cypress.
Coastal Sage-Chaparral Scrubland
Formally known as the California Coastal Sage and Chaparral Subecoregion, this diverse scrubland community is dominated primarily by sclerophyllous shrubs. Common species include sagebrush, chamise, and buckwheat, with succulents such as prickly pear and yucca also abundant. Many shrubs in this community rely on fire for seed germination, and increased post-glacial wildfires beginning ~13,000 years ago facilitated the dominance of this vegetation type across southern California today.
Live Oak Parkland
Live oak parkland is characterized by a canopy where 20-60% of it is composed of tree-sized coast live oaks. Other trees intermix and form their own woodlands within this plant community such as bay laurel and black walnut. These trees form "islands" of flora distinct from the surrounding landscape, creating a wetter, shaded understory beneath their canopy. This plant community gradually transitions into open oak savanna, interspersed with meadows of chaparral vegetation.
Coastal Prairie
California coastal prairie is a grassland plant community dominated by perennial bunchgrasses like Tufted hairgrass. Other vegetation like sparse shrubs dot the landscape, while wildflowers like golden poppies, goldfields, and western blue-eyed grass blanket the hills with color when they bloom simultaneously in the springtime. This plant community relies on regular disturbance, like grazing from large mammals, in order to maintain its composition and resilience to environmental stressors such as droughts.
Riparian Woodland
Riparian woodlands can be found thriving along streams, springs, and gullies, where water-dependent plant life can flourish. Unlike most plant communities that rely on rainfall for water, riparian woodlands consist of plants that require constant access to surface water or groundwater. This plant community has a multi-layered canopy, dominated by arroyo willow, western sycamore, white alder, and black walnut, along with an understory of herbs, sedges, and water-plantains.
Coastal Terrace & Dunes
Much like Santa Monica beach today, the coastline during the last glaciation would have been a raised beach, or a beach bordered by coastal bluffs. Below on the wave-cut platform are where sand dunes form, and are covered in salt-tolerant vegetation. Not far from the beach are sea stacks that have weathered from the coastal cliffs as they've retreated from wave erosion. Exposed sea stacks that were formed when sea level was higher, and then uplifted, can be found farther inland.
Coast Redwood Grove
Coast redwood groves can be found within the humid upland riparian canyons surrounding the Los Angeles Basin. Californian coast redwoods can grow upwards of 300 feet, with their height and morphology constricted by the amount of annual rainfall they receive in southern California. The emergent canopy is primarily comprised of coast redwood, with a subcanopy of pine and juniperus. The understory is dominated by humidity-loving and shade-tolerant plants like ferns as well as fungi.