Fire Ecology Trail Guide

The Coastal Sage Scrub plant community in the San Gabriel Valley occurs generally below 1,500 feet on sloping land below the foothills. This community of low, scrubby plants is the most endangered vegetation type in Southern California, because of pressures from urbanization, flood control projects, and rock quarries. California Sagebrush is the dominant shrub with other common associates being White Sage, Black Sage, and Flat-topped Buckwheat. Plants in this group are adapted to the hot, dry summers and cool, moist winters we have in Southern California. Their leaves may be small, sticky, hairy or whitish-coated, to reduce water loss and often are fragrant. Many species are drought deciduous; they loose their leaves to reduce stress during the dry Summer and Fall months.

Individual plants of the Chaparral community, which dominates the slopes above the park, are found on the trail. Plants in these communities commonly respond to fire in two ways. They may regrow from seed from the original plant before the tire or they may resprout vigorously from the basal stump (burl) and roots left behind. Species using these two strategies are called “Seeders” vs. “Sprouters”. Many plants use both techniques to reestablish. Some seeds require heat to break a tough outer coat and some need charcoal or smoke from tire to sprout. Look for evidence of charred wood at the bases and on old stems of shrubs along the trail. 

Stop 3. Scale Broom

Lepidospartum squamatum The Scale Broom shrub, a member of the Dandelion group of the Sunflower family, has rigid broom-like green branches and ls found only in washes and on alluvial fans. The leaves are usually reduced to tiny scales along the stem. except briefly in the rainy season when the hairy, gray-green leaves appear on new stems. Fall brings an abundance of golden yellow flowers, resembling tiny dandelions. Miniature parachute pulls of seeds provide the familiar seed dispersal method of this plant group. Scale Broom has recovered well following the fire, resprouting from the root base.

Stop 5. Showy Penstemon

Penstemon spectabilis This plant derives part of its name from the five (pen) stamens (stemon) the flowers contain. One stamen is sterile and covered with hairs. The beautiful lavender flowers bloom in the spring. Showy Penstemon has spread widely after the fire and covers several acres here.

Stop 7. Western Sycamore

Platanus racemosa The pale-barked tree above you is best recognized by its five-fingered leaves, somewhat like a maple. and balls of flower clusters which hang from the branches. Sycamore is generally associated with riparian woodlands but may be found some distance from standing water. A great shade tree in summer, it drops its leaves in the winter. The blackchinned hummingbird gathers soft fuzz from the underside of sycamore leaves to add to its nest.

Stop 9. Mountain View

Look to the North here, between these two oaks. All of the mountain slopes you see burned in the October 1993 fire. Henninger Flats is located in the long, flat ridge of pine trees to the east (right). Erosion greatly increases following fires on steep slopes and canyon bottoms – much of this material flows through the canyon during major storms.

Stop 11. Whipple Yucca

Yucca whipplei This familiar plant of the foothills and hillside chaparral is neither a “cactus’ nor a ‘succulent” but a member of the Lily Family (formerly placed in the Agave Family). The long, still, spine-tipped leaves must be avoided by hikers but were useful to local Indians as a needle and thread, as cordage and for making sandals.

After 8 to 12 years of basal growth the yucca sands up its large flower stalk, produces showy masses of cream colored flowers, then dies. Flower pollination ls accomplished by the Yucca Moth whose larvae benefit from eating some of the seeds in the developing pod. This ls a classic ecological concept called mutualism.

Stop 13. Mulefat

Baccharis salicfolia Mulefat ls a very common shrub found all over Southern California in damp to wet environments. Its willow-like loaves range from 1 to 3ó inches long with scattered teeth around the outer half. This Sunflower Family shrub has male and female bushes which bear slightly different flowers.

Stop 15. California Sagebrush

Artemisia californica California Sagebrush, a pleasant scented low shrub with feathery narrow gray leaves, ls a dominant member of the Coastal Sage Scrub plant community. It may be found in almost all parts of Eaton Canyon, from hillside to stream bottom. The early Spanish used it as a tea for bronchial problems, as well as a wash for wounds and swelling. Early miners used it to drive fleas from their bedding. Sagebrush resprouts from the root base but also grows back from seed following fire. On your way to the next stop, think about what you would do if you were an animal and a fire came through. Fire and Animals Fire affects animals as well as plants, but some survive better than other. The Dusky-footed Woodrat lives in a large house of sticks and many are killed during fires. Cottontail Rabbits and California Ground Squirrels live underground and can take shelter there or flee ahead of the fire. Birds, of course, can fly but some may head deep into shrubs for cover and perish in the fire. Mule Deer, Coyotes and many birds were seen in the canyon, immediately following the fire and populations have recovered well.

Stop 17. Prickly Pear

Opuntia littoralis The Prickly Pear cactus grows in dense clusters with flat, broad, oval pads covered with numerous spines. The pads are actually flattened stems, not leaves. The showy yellow flowers attract numerous insects. and are followed by reddish-purple fruits. These Cactus apples (or pears) are delicious in jellys and jams. after the spines have been removed. Fleshy water-filled pads allow cactus to survive fire quite well. unless there are heavy grasses growing among the patches. The grasses concentrate the fire within the stand of prickly pears and the extreme heat may kill the cactus.

Stop 19. Poison Oak

Toxlcodendron dlversilobum Poison Oak is one of the most common plants in the Park. It is easily recognized by its leaves, each of which ls divided into three separate leaflets. The leaves of Poison Oak are green during most of the late winter early spring growing season, but may turn red or yellow in the summer or fall. Like other deciduous plants, Poison Oak drops its leaves in late fall and winter.

All parts of the plant contain an oil that causes blistering and itching upon contact with human skin, but has no effect on animals. Wash with soap and water as soon as possible if you believe you came in contact with this plant.