VI. PLANT COMMUNITIES

C. COASTAL LIVE OAK WOODLANDS Coastal live oak woodlands occur in the more mesic areas of coastal California from Sonoma County south into Baja California. The term "woodland" is used instead of "forest" because woodlands tend to be more open and sunlit, their canopies sometimes touching, but rarely overlapping. Woodlands are typically found below 5000 feet in soils too dry to support a forest. They are found within a 50-mile radius of the coast, out of the influence of salt spray. Fog is common in these areas. Soils are typically well drained. Although certainly not limited to these areas, coastal live oak woodlands are quite common in the ravines and moister drainages between grassy hillsides, as is the case in Poly Canyon. These woodlands are also common on north-facing slopes. The dominant plant is coast live oak (Quercus agrifolia), which often is found in monotypic (pure) stands. Twenty-million-year-old fossils of coast live oak found in the Pacific Northwest reveal that there has been little change in the species over time. The coast live oak has several features that enable it to survive the hot dry summers of the Mediterranean climate where it is found. It has a specialized root system including a deep tap root and tiered feeder roots which collect moisture at several levels in the soil. Also, its xylem tissues (the ones dedicated to the transport of water from the roots to the leaves) tend to harden as the summer drought progresses. Its evergreen, sclerophyllous leaves have a thick waxy cuticle which, in conjunction with stomata (pores) that close in response to seasonal midday aridity, keeps water losses at a minimum. Other characteristics suggestive of hot summer and/or summer drought adaptedness are the leaves found on different parts of the tree. Variation in leaf size and shape is common among oaks, the coast live oak being no exception. However, with all this, two main types of leaves have been identified. The outermost leaves are thick, small, and convex with two to three layers of photosynthetic cells. These characteristics make them good at releasing excess heat, collecting light, and also manufacturing food. Leaves found beneath these toward the middle or basal parts of the tree tend to be thinner, wider, and flatter with only one layer of photosynthetic cells. These leaves are protected from the most intense heat by being in the shade of the outermost leaves, yet they are still able to photosynthesize. This sort of shade-adapted leaves is also found on seedlings growing in low-light. An intrinsic part of coastal live oak woodland ecology is fire. Coast live oaks have a thick bark that insulates inner tissues from relatively low-intensity (modest heat over a short time), infrequent fires. A higher-intensity fire can be survived by crown-sprouting, when the above-ground portion of the tree is killed, but the buried root crown resprouts. In some cases, sprouts can also be seen originating from the trunk. Buried acorns may also sprout after a fire. There are certain adaptive advantages to fire in this community: other plant species that compete with oak seedlings and saplings for water and nutrients are eliminated; more mineral nutrients become available as rains leach them from burned wood and ashes; and debilitating insect pests are temporarily eliminated from the foliage, bark, and buds. As with most factors affecting growth and development, even with fire there is an ideal frequency range which promotes health in the community. If fire is suppressed too long, non-native species overrun the understory, killing oak seedlings and saplings that are not well established. However, if fires occur too frequently, seedlings and saplings are killed off and viable acorns are eliminated from the area, stalling for many years a healthy regeneration of the woodland. In mesic stands, where moisture is available, typical understory species include California blackberry (Rubus ursinus), creeping snowberry (Symphoricarpos mollis), toyon (Heteromeles arbutifolia), and western poison oak (Toxicodendron diversilobum). An herbaceous layer would include bracken fern (Pteridium aquilinum), California polypody (Polypodium californicum), and miner's lettuce (Claytonia perfoliata). In drier areas, where the oak canopy is not as dense, the coastal live oak woodland forms an ecotone with one of several adjacent communities. Where it intergrades with a grassland, its understory has a higher component of grasses than shrubs. On steeper slopes, there are usually more shrubs in the understory as the woodland intergrades with chaparral - manzanita (Arctostaphylos spp.), chamise (Adenostoma fasciculatum), fuchsia-flowered gooseberry (Ribes speciosum), and California lilac (Ceanothus spp.) - or with coastal scrub - California sagebrush (Artemisia californica), black sage (Salvia mellifera), coyote bush (Baccharis pilularis), or sticky monkeyflower (Mimulus aurantiacus). Western poison oak (Toxicodendron diversilobum) is ubiquitous. In Poly Canyon there are several woodland sites that border grassland communities. Here a weedy non-native, Italian thistle (Carduus pycnocephalus), forms a dense, monotypic cover beneath the oaks. Controlled grazing of sheep under holistic resource management regimes has been used to repopulate similar areas with more desirable native perennials. This is discussed further under the grasslands section. In Poly Canyon, the single dominant species in coastal live oak woodlands is: *Coast live oak, encina (Quercus agrifolia, Fagaceae) Associate species include: *Toyon, Christmas berry (Heteromeles arbutifolia, Rosaceae) *California bay, California laurel, pepperwood, bay-laurel (Umbellularia californica, Lauraceae) Understory species include: *California sagebrush, coastal sagebrush (Artemisia californica, Asteraceae) Aster (Aster radulinus, Asteraceae) *Sticky monkeyflower, bush monkeyflower (Mimulus aurantiacus, Scrophulariaceae) Goldback fern (Pentagramma triangularis, Pteridaceae) *California coffeeberry (Rhamnus californica, Rhamnaceae) *California blackberry (Rubus ursinus, Rosaceae) *Hummingbird sage, pitcher sage (Salvia spathacea, Lamiaceae) *Blue elderberry (Sambucus mexicana, Caprifoliaceae) Hedge-nettle (Stachys bullata, Lamiaceae) Creeping snowberry, trip vine (Symphoricarpos mollis, Caprifoliaceae) *Western poison oak (Toxicodendron diversilobum, Anacardiaceae) Descriptions of Poly Canyon's coastal live oak woodland plants follow. *Coast live oak, encina (Quercus agrifolia, Fagaceae) This is a 6- to 25-m. (20- to 82-foot) evergreen monoecious tree. It can be extremely long-lived (usually more than 250 years, even 600). It has 21/2- to 6-cm. (1- to 21/2-inch) leathery, spiny-toothed, ovate, dull green leaves. The upper surface of the leaves is convex. The lower surface often looks as if it has cobwebs in the axils of its veins; actually, these are tufts of tiny star-shaped hairs. The male inflorescence is a catkin near the base of a twig, and the female inflorescence is a single flower surrounded by a cup of scale-like bracts. Blooms appear from March through April. The 25- to 35-mm. (1- to 11/2-inch) slender, pointed acorns mature in one year. Coast live oaks also occur in valleys, on grassy hillsides, and in riparian woodlands. Quercus is the ancient Latin name for oak. From this name we derive "cork," a product of some species of oak. In turn, Quercus comes from two Celtic words: quer "fine" and quez "tree." Agrifolia was a printer's error for aquifolia, meaning "holly-leafed." Encina has been highly valued by Chumash, who have used its wood for fuel, bowmaking, games, cooking utensils, and cradles. They also used its bark for a red dye for hides. They used its bark and galls in medicine (tannins have astringent properties). Its bellotas (acorns) have been used as food for at least 5,000 years. The acorns are dried, finely ground, and leached of tannins, then cooked into an unseasoned mush. In trade, five hatfuls of acorns was worth one hatful of chia, and two hatfuls of acorns was worth one of islay.



Associated species include:

*Toyon, Christmas berry (Heteromeles arbutifolia, Rosaceae)

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*California bay, California laurel, pepperwood, bay-laurel (Umbellularia californica, Lauraceae) This is an aromatic evergreen shrub or tree that grows to 45 m. (148 feet) tall. It has 3- to 10-cm. (11/2- to 4-inch) shiny, deep green lanceolate leaves. Six to ten yellow-green 6-mm. (1/4-inch) flowers bloom in umbels from December through May. The 2-cm (3/4-inch) fruit, a drupe, resembles an olive and ranges in color from green to dark purple. Bay-laurel is also found in canyons and valleys and in some chaparral habitats. Umbellula is Latin for "small umbel." Californica means "of California." Laurel is the Spanish name. Early Californians used the burls of laurel to form bowls. They used the wood in rituals. Tea from the leaves was used by them to fight colds. The leaves were mixed with lard as a cure for diarrhea. Rheumatism was treated with laurel leaves in a hot bath. Leaves have been used to flavor foods, as a flea and witch repellant, and crushed leaves sniffed to cure headaches. The fruit was eaten raw or boiled; the kernel roasted and ground for cake flour.



Understory species:

*California sagebrush, coastal sagebrush (Artemisia californica, Asteraceae)

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Donald Myrick Aster (Aster radulinus, Asteraceae) This is a 2- to 7-dm. (8- to 28-inch) perennial. It spreads by rhizomes. Its 4- to 10-cm. (11/2- to 4-inch) elliptic, pointed, serrate leaves occur along a hairy stem. The inflorescence is a flat-topped cyme or panicle. Showy white to purplish ray florets bloom from July through October. The fruit is a hairy achene. This aster is found primarily in dry woods. Aster is Greek for "star." Radulinus means "scraper."





*Sticky monkeyflower, bush monkeyflower (Mimulus aurantiacus, Scrophulariaceae)

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*Goldback fern (Pentagramma triangularis, Pteridaceae) This plant has 3- to 18-cm. (11/4- to 7-inch) fronds that are somewhat triangular in shape. The fronds are twice to three times pinnately lobed. There is a waxy, yellow exudate on the lower surface of the fronds, hence the common name "goldback fern." Sporangia occur along the veins, rather than in sori. Goldback fern is found primarily near rocks and boulders in shaded areas. Penta is Greek for "five." Gramma means "letter" or "writing."

*California coffeeberry (Rhamnus californica, Rhamnaceae)

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*California blackberry (Rubus ursinus, Rosaceae) This is an evergreen, prickly, mounding and/or spreading shrub. It has prickly leaves measuring between 4 and 15 cm. (11/2 and 6 inches). The leaves are simple and palmately lobed or divided into three leaflets. The 5- to 25-mm. (1/4- to 1-inch) white flowers bloom from March through June. Then 2-cm. (3/4-inch) aggregates of black berry-like fruits (drupes) develop through the summer. One might confuse blackberry with poison oak. However, poison oak has no prickles on its stems or leaves, and the flowers and fruits look completely different. California blackberry occurs in moist places in shrublands and at streamsides. Rubus comes from Latin and means "bramble." Ursinus means "bear." Moras or zarzamoras (zarza means bramble) were eaten by early Californians unless they were found growing in a damp place. The root was boiled into tea with which to cure diarrhea.





*Hummingbird sage, pitcher sage (Salvia spathacea, Lamiaceae)

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*Blue elderberry (Sambucus mexicana, Caprifoliaceae)

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Hedge-nettle (Stachys bullata, Lamiaceae) Hedge-nettle is a 4- to 8-dm. (16- to 32-inch) perennial. It has opposite, ovate, round-toothed, aromatic 3- to 18-cm. (11/4- to 7-inch) leaves that are somewhat puckered and fuzzy. It has 5-cm.+ (2-inch+) whorls of flowers around the stem. The flowers are two-lipped. The corolla tube measures 7 to 10 mm. (1/4 to 1/2 inch). Petals are pink to lavender-red, with white markings on the lower lips. The flowers bloom from March through May. The fruits, nutlets, are inconspicuous. Hedge-nettle is common on dry slopes. Stachys means "spike," referring to the spikes of flowers. Bullata means "puckered," referring to the leaves.



Creeping snowberry, trip vine (Symphoricarpos mollis, Caprifoliaceae) Creeping snowberry is a low-growing, spreading deciduous shrub with 11/2- to 6-dm. (6- to 24-inch) stems. It has 1/2- to 3-cm. (1/4- to 11/4-inch) opposite, thin, oval leaves. Its paired, hanging, bell-shaped, pinkish-white flowers bloom from April through June. Then, 8-mm. (1/3-inch) white berries develop, usually in pairs, in the late summer and early fall. Creeping snowberry is found along streamsides, on ridges and slopes, and in open places in woodland habitats. Symphoricarpos means "fruit born together." Mollis means "soft, tender, flexible." The local Spanish names were oreja de ratón ("rat's ear," referring to the leaf shape) or escoba (broom, referring to one of its uses). Early Californians wove branches into baskets. They also made toy arrows of the branches. The fruit was eaten, primarily by children.





*Western poison oak (Toxicodendron diversilobum, Anacardiaceae)

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