The chaparral community lies west of the Sierra Nevada summit and Mojave Desert
Between elevations of sea level to around 10,000 feet
Chaparral Area in California by County (in acres)*
San Diego 1,003,441
Los Angeles 553,789
Riverside 499,160
Santa Barbara 440,645
San Luis Obispo 417,718
Monterey 369,345
Ventura 326,447
San Bernardino 276,010
San Benito 246,623
Santa Clara 188,427
Orange 111,550
Marin 37,566
San Mateo 36,152
Santa Cruz 32,328
*From Fried, J.S., C.L. Bosinger, and D. Beardsley. 2004. Chaparal in Southern and Central Coastal California in the Mid-1990's: Area, Ownership, Condition, and Change. USFS Resource Bulletin PNW-RB-240
Chaparral was part of the Madro-Tertiary Geoflora
Beginning about 65 million years ago
- The Madro-Tertiary Geoflora comprises
- Semiarid live oak-conifer woodland
- Chaparral
- Arid subtropic scrub
- Desert grassland
- Desert vegetation
- The climate of Western North American began to cool and became more arid
- Partly in response to the initial uplift of the Sierra Nevada and Coast Range.
- And partly due to falling global temperatures and increasing global aridity.
- The rainshadow that resulted from these mountain barriers allowed the Madro-Tertiary Geoflora (from the Sierra Madre of Mexico) to expand it's range and replace some of the Arcto-Tertiary plants in California, the Columbia Plateau, and Western Oregon.
Redwood, fir, cedar, spruce, and hemlock trees and their ancestors
- Subsequent uplift of the Cascades increased the rainshadow effect in the interior PNW especially in the last ~20 million years.
- Rainshadow effects of the Olympic Mountains and Vancouver Island have created enough aridity for some of the drought-adapted Madro Tertiary Geoflora to extend well into Western Canada.
Most of the plants of Madro-Tertiary Geoflora
- Are drought adapted with some combination of small, deciduous, or waxy leaves.
- Some are found in fairly high precipitation zones (such as the coast) if the soils are coarse-grained with minimal moisture holding capacity.
Chaparral borders with several other important CA plant associations:
- In Southern California- integrates with coastal shrub
- In Northern California- integrates into grasslands and also xerophytic mixed conifer forests
- On foothill sites it integrates into oak woodland types
- Within chaparral community, various forms of riparian woodlands and riparain scrub exists
Chaparral varies greatly in:
- Species composition
- Size
- Cover
- Appearance
From one area to the next and within the same stand
Chaparral is distinguished by the sclerophyll leaf:
- Small, thick stiff and usually evergreen
- Some are moderatly to heavily wax coated
- Plants have extensive root systems to endure the typical Mediterranean summer of hot, dry conditions
- Chaparral shrubs have many branches to support the leaf canopy.
- Stem flow of precipitation is important
- Through stemflow, water is delivered to the base of each shrub
- Soils are loose and friable, protected by leaf litter
- May recieve up to 30% of total precipitation to the base of plant
Soils
Soils are characterized as being youthful = Entisols
Storie and Harricline (1958) estimated that 85% of chaparral soils are lithosols= physically disentegrated igneous-metamorphic parent rock
Generally the texture is
Sand (40-to 80%)
Silt (20 to 30%)
Clay (<20%)
Soils are highly porous, rocky and low in nutrients
Creates rapid infiltration, but low water holding capacity
Topography
Generally steep and rough resulting in these shallow rocky unstable soils
Surface materials are highly erosive because of coarse texture (sandiness) and steep angle of repose
Slope movement is common both during the wet (erosion) and dry (creep) conditions
Creep may exceed wet erosion rates
- After a fire dry creep may be 10 to 16 times greater then prefire rates
Vegetation Communities
There are three (3) Major subdivisions covering a combined area of 11 million areas
#29 True Chaparral
#30 Montane Chaparral
#32 Coastal Sagebrush
#29 True Chaparral
Adenostoma/Arctostaphylos/Ceanothus
- Very dense vegetation of broadleaf evergreen sclerophyll shrubs
- Largest community
- 8.5 million acres
Dominates include:
A) Chamise- Adenostoma fasciculatum
B) Manzanita- Arctostaphylos ssp
C) California Lilac- Ceanothus species
#30 Montane Chaparral
Arctostaphylos/Chrysolepis/Ceanothus
- Dense vegetation of broadleaf evergreen shrubs, occasionally with some some needleleaf evergreen and broadleaf decidious trees
- .6 million acres
Dominants are:
A) Green leaf manzanita (Arctostaphylos patula)
B) Bush Chinquapin (Chrysolepis sempervirens)
C) Snowbush (Ceanothus velutinus)
Great Chaparralians
California Grizzly Bear
Once the ruler of the chaparral, the last California grizzly was seen in 1924. The last one in Southern California was shot in 1908.
California Condor
Fire
Fire is an important factor in this environment
Axelrod (1958,1977) has shown that fire and summer drought were the major environmental agents that shaped the chaparral over the past 2 million years.
California chaparral is one of the most fire susceptible vegetation types in the world: 1)Shrub density 2)Summer dryness
3) A volatile foliar substance within many of the chaparral plants
Burn to Live & Lives to Burn
From the California Chaparral Institute;
- Old-growth chaparral is a beautiful, healthy ecosystem. It does NOT need fire to "renew" or clean out "built-up" or "over-grown" vegetation.
- As an ecosystem, old-growth chaparral does not "need" fire to remain healthy.
- The term "over-grown" is a value judgment that's applicable to our managed backyards and urban parks, not wild plant communities.
- Old-growth chaparral continues to be a productive ecosystem, growing fresh, new growth in its upper canopy every year.
- In fact, some chaparral plants require the leaf litter and shade provided by older chaparral stands for their seeds to germinate successfully.
- Instead of becoming "trashy" or unproductive, as some have claimed, old-growth chaparral (in excess of 40-50 years) is actually just beginning a new cycle of life.
Concern over Fire
Old-growth chaparral being removed by a mechanical "masticator".
- Will this result in fire risk reduction?
- Or create additional resource degradation including:
- Loss of native species
- Destruction of soil crust
- Introduction of invasive annual grasses
- Formation of rills and gullies
- Sediment delivery to watersheds.
- "Treatments" near homes is the most effective in protecting structures from ignition.
And one more thing...
Coastal Scrub- PNV #32
Also refered to as soft chaparral, coastal sage scrub, coastal sage brush association
Within Terrestrial Vegetation of California
by Barber and Major
1) Northern Coastal Scrub
2) Coastal Sage Scrub
3) Coastal Sage Succulent Scrub
Extends from Southern Oregon to Baja as follows
1) Northern Coastal Scrub- From southern oregon to Big Sur
2) Coastal Sage Scrub- Big Sur to San Diego
3) Coastal Sage Succulant Scrub-San Diego to Baja
- The annual rainfall in the Northern Coastal Scrub plant community can vary from 25 to 75 inches.
- Temperatures remain mild throughout the year because of the proximity to the ocean.
- Although the temperature is mild here the wind and salt spray make this a harsh environment for plants.
- Plants remain low forming a dense or open scrub.
- This cover is home to such birds as the California Thrasher, a species endemic to California.
- Some common species include
- California Lilac (Ceanothus thyrsiflorus var. repens)
- Coyote Brush (Baccharis pilularis)
- Coastal Golden Yarrow (Eriophyllum staechadifolium)
- Seaside Daisy (Erigeron glaucus)
- Sticky Monkey Flower (Mimulus aurantiacus).
- Thimble berry and black berries are also prevalent in the coastal sage scrub plant community.
Other shrubs include:
- California yerba santa (Eriodictyon californicum)
- Coast silk-tassel (Garrya elliptica),
- Salal (Gaultheria shallon)
- Yellow bush lupine (Lupinus arboreus).
- Herbaceous species include Western Blue-eyed Grass (Sisyrinchium bellum), Douglas iris (Iris douglasiana), and grasses.
Coyote brush- Baccharis pilularis
California Yerba Santa- Eriodictyon californicum
Salal- Gaultheria shallon
It is characterized by low-growing aromatic, and drought-deciduous shrubs adapted to the semi-arid Mediterranean climate of the coastal lowlands.
Characteristic plants include:
- California sagebrush (Artemisia californica)
- Black sage (Salvia mellifera)
- White sage (Salvia apiana)
- California buckwheat (Eriogonum fasciculatum),
- Coast brittle-bush (Encelia californica)
- Golden yarrow (Eriophyllum confertifolium)
- Toyon (Heteromeles arbutifolia)
- Lemonade berry (Rhus integrifolia)
- Along with other shrubs and herbaceous plants, grasses, and in some places, cacti and succulents
California sagebrush (Artemisia californica)
Toyon (Heteromeles arbutifolia)
White sage (Salvia apiana)
Black sage (Salvia mellifera)
- It originally covered most of what is now the urbanized portion of San Diego.
- Along the county's north coast (on sandstone cliffs bordering the beach) lies a special strip of Coastal Sage Scrub that is home to one of the rarest pine trees in the country, the Torrey Pine.
Endangered in the wild, Torrey pine is planted as an ornamental tree
Torrey Pines State Reserve
Torrey Pines State Natural Reserve is located within San Diego city limits
- Remains one of the wildest stretches of land on the Southern California coast
- 2000 acres of land set aside ---- before San Diego was developed
- The chaparral plant community, the rare and elegant Torrey pine trees, miles of beaches, and a lagoon that is vital to migrating seabirds.
- Salt pruning is the process by which saline mists generated by seawater are driven ashore by winds
- Alter the shape of trees
- The process of salt pruning selectively degrades foliage and branches on the windward side of the plant facing the body of saline water.
- The resultant growth form is an asymmetrical plant form, swept back away from the ocean.
Presumably, colder temperatures, or perhaps increased rainfall limits the northern distribution of many of these succulent species. Some of the succulent species are actually found in San Diego County
Some of the plants characteristic of this community includes:
- Agave shawii, a large, dark green agave at maturity
- Coreopis maritima, a member of the sunflower family that dies back to a succulent root during the dry season
- Fraxinus trifoliata, a small ash native to Baja California
- Ambrosia chenopodifolia, another member of the sunflower family, but one with wind pollinated flowers.
Climate
Occupies dry slopes and ridges of thin soils
Temperature of chaparral is moderate but fluctuates considerably
Mean summer temp range from 82 F- 94 F
The overriding abiotic factor of the chaparral is precipitation
Rainfall occurs from October through April
About 85% comes during December through April
The growing season ranges from 340 days to 360 days during normal years
A California condor taking a rest from soaring over the Los Padres National (Chaparral) Forest. Photo: Lane Frank