Soft Chaparral | Hard Chaparral
Plant Communities of Mount Diablo State Park
Soft Chaparral

Also called coastal scrub or coastal sage scrub, soft chaparral is dominated by small shrubs with "soft" leaves (leaves with a pliable, thin texture). Leaves may be heavily scented -- smelling of sage, turpentine, or mint -- to keep animals from browsing them. These fragrant oils also evaporate on hot days to cool leaves and inhibit growth of competing plants. All of these ploys prevent shrubs from losing precious leaves, since it costs energy and water to make new ones. Yet in summers with prolonged drought, soft chaparral shrubs may lose most of their leaves as a last-gap effort to keep from dehydrating faster than roots can replenish water from bone-dry soils. Winter rains bring temporary supplies of water during which leaves are replaced.

Soft chaparral is typical of rocky promontories in the fog belt, but components of this same community appear as temporary replacements for hard chaparral shrubs after brush fires.

Soft chaparral shrubs are varied, with some particularly aggressive pioneer species, such as coyote brush (Baccharis pilularis). Others include California sagebrush (Artemisia californica), with broad dark green leaves whose edges curl under; sticky monkeyflower (Diplancus aurantiacus), with sticky, viscid green lace-shaped leaves, again with curled-under edges; black sage (Salvia millifera), with highly aromatic dark green, narrowly triangular leaves; blue witch (Solanum umbelliferum), a green-twigged shrub whose fuzzy, light green leaves are cast away in summer; and poison oak (Toxicodendron diversilobum), with shiny, triparite leaves, which are lost early during severe drought.

Link to California Chaparral Field Institute website.

Excerpted from MDIA's book, Plants of the East Bay Parks by Glenn Keator, Ph. D.

Soft Chaparral: Black sage, Salvia mellifera, Glenn Keator

Hard Chaparral

Hard chaparral replaces soft chaparral in hotter, drier inland areas, usually on steep, rocky slopes. (Shrubs favor the summer heat of south facing slopes.) From a distance the dense, tall shrubberies of hard chaparral look like a uniform dark green velvet draped over the mountainsides.

Hard chaparral is so named because its component species have stiff, tough, durable leaves that are seldom shed even at the peak of summer's heat. In fact, the main attribute of such leaves is their long tenancy; shrubs do not have to expend valuable water to create a new set of leaves each year should rains be sparse.

Leaf design varies as much as the several families and general represented. Manzanitas make stiff ovate leaves that are turned edgewise or vertically to avoid the full brunt of sun -- and some kinds, like big-berry manzanita (Arctostaphylos glauca), have whitish leaves that reflect away excess light and heat. Chamise (Adenostoma fasiculatum) uses narrow, needle-like leaves clustered together to conserve water by minimizing surface area exposed to sun. Wild lilacs (ceanothuses) cover their leaves with a thick, waxy covering that makes them shiny. Bush poppy (Dendromecan rigida) has bluish green leaves held obliquely to reflect away heat and minimize the impact of the fierce summer sun.

In addition to their ingeniously designed leaves, chaparral shrubs have deeply probing roots that serve to hold shrubs in place and find sources of deeply hidden water. Roots may also carry on chemical warfare with neighboring shrubs to prevent invasion into their own root zone. Chaparral pea (Pickeringia montana) and ceanothuses have tiny knobs on their roots that house nitrogen-fixing bacteria. As a result, such shrubs can move onto nutrient-poor soils; when they die they may pave the way for other shrubs to move in by releasing these nitrogenous compounds into the soil.

Chaparral shrubs grow into nearly impenetrable canopies -- from head high to well over ten feet. The best way to pass through is to crawl beneath the branch canopy as small mammals do. Chaparral has been called the elfin forest in allusion to this dense but short forest-like growth pattern.

Link to California Chaparral Field Institute website.

Link to Belorussian Translation website

Excerpted from MDIA's book, Plants of the East Bay Parks by Glenn Keator, Ph. D.

Hard Chaparral: Mount Diablo Manzanita, Arctostaphylos auriculata, Kevin Hintsa

© 2020 by Mount Diablo Interpretive Association