Relict Species: Engelmann Oak

Relict, n: a remnant or survivor.

Species, n: a distinct sort or kind

The Engelmann Oak (Quercus engelmannii)

For my own satisfaction, and hopefully for somebody else out there who likes trees, I’m going to write about some of the remarkable remnant species of trees and plants that I come to know in California. A relic species is that of which only a tiny remnant remains from a species that may have once dominated its respective region. One of the most famous examples of this is the Coast Redwood, which, at one point, was the dominant tree on the northern California coast (and perhaps the entire world). As a result of human activity and environmental change, the Coast Redwood now only exists in remnant populations in the rare spots that still support the climate in which the trees thrive.

In essence, relic species are leftovers from a time when the world was colder, damper, and emptier. Unchecked and uninterrupted, these species flourished in the way that buildings and freeways now flourish. When white settles moved in, and as the climate began to change, these populations diminished, leaving only small pockets that were spared just in time by conservation efforts like parks and recreation areas.

California is home to some famous relics, like the afore-mentioned redwood, the Giant Sequoia of the Sierras, the Torrey Pine – rarest of all North American pines, the Monterey Cypress, and the 4,800 year old Bristlecone Pine. Numerous other species, less well known, but still beautiful in their own ways, also flourish throughout the state, clinging to survival in isolated pockets of preserved terrain.

One of these species is the Engelmann Oak. Most oak tree names bear a signifier that describes something about its feature. The coast live oak is a live oak that appears along the coast. The black oak is so called because of its dark bark (not because of its brilliant leaves, for which it could be called the rainbow oak). The Engelmann is also known by other names, such as the Pasadena or Mesa oak.

These oaks are now hard to find in Pasadena, now that Pasadena is a part of the patchwork knit of sprawl in Los Angeles. Mesa oak describes the tree’s surroundings, which are generally on mesas that lie below the typical winter snow line. However, the common name is derived from George Englamann, a German-American botanist who did extensive studies in the Rocky Mountains and Northern Mexico. These disparate locations account for why Engelmann had a cold-weather spruce and a warm-weather oak named after him.

The oak is a remnant from a much larger population that stretched across the California deserts into Arizona and Northern Mexico. This population existed in the cooler, damper past, when much of coastal California still had forests that consisted of cedars, cypresses, oaks, sycamores, and pines. As the climate changed from warmer to dryer, large deserts appeared, causing the water-loving tree ranges to shrink until finally reaching their present range in the portions of coastal Southern California that provide the ideal conditions.

Like people, all trees are a product of their environment, and as the available supporting environment vanished, so did the Engelmann oaks. They favor climates at least 20 miles from the ocean on open, grassy mesas between 500′-3,900′. Unfortunately, so do housing developers. You can find a few at Huntington Library in the San Gabriel Valley, but to find them in the wild, one must look in the Santa Ana Mountains, specifically on the south east branch that contains the Santa Rosa Plateau. They are also present in smaller numbers on some of the rolling plateaus and inner valleys in San Diego County such as Daley Ranch and Black Mountain in Ramona. Among its relatives are Valley and Blue Oaks from the central valleys of Southern and Central California. More closely related oaks can be found on “Sky Islands” in Arizona, Mexico, and New Mexico.

The oak itself can get up to 60′ tall and live up to 200 years. It is drought-deciduous, which means it tends to drop its leaves during the hot, dry summers and then regrow them during the winter. This is opposite to the way most deciduous trees behave. This trait separates the tree from live oaks, which never lose all of their leaves, and white oaks, which lose all of their leaves in the classic deciduous patterns.

But beyond those dry stats, the Engelmann oak is a beautiful tree. With sparser and more lightly colored foliage than coast live oaks, with which it shares terrain, Engelmanns often become twisted and gnarled, although they weep gracefully with their lengthy branches dipping into the drying grass below. Their bark comes in pale grey plates that cause deep shadows, giving the bark a black and white look. They provide a welcoming habitat for birds, and so the area around them can be noisy. Because they favor mesas, often covered with grass, they form a classic California scene of pastoral beauty: the oak woodland.

Fortunately, this tree now exists in some well-protected place. The best place to see them first-hand is at Santa Rosa Plateau, the last place where they grow in profusion.

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