The Chapparal is a hot dry place in the summertime.
The true western chaparral occurs mostly in southern and central California. It features a highly-contoured landscape characterized by a mixture of grassland and scrub forests. Within this region, the soil of the chaparral differs significantly, and soil type is heavily influenced by rock layers that exist underground. Generally speaking, the soils of the chaparral are shallow and unable to hold much water; erosion is a frequent process.
Serpentine Soil
Serpentine is a mineral that originates within the earth's mantle. Through uplifting of the earth's surface, this mineral forms outcrops along the San Andreas, Hayward and other active faults in California. Soil created from this mineral tends to be high in toxic elements such as magnesium, nickel and chromium, and lacking in some of the more essential elements as calcium and nitrogen. As a result, grasslands have a difficult time growing in a serpentine soil, but certain trees and shrubs, such as the manzanita and Clarkia can thrive in these conditions.
Non-Serpentine Sedimentary Soils
Even in Southern California, soils that have formed from a sedimentary parent rock, such as sandstone, are common and can be found in many chaparral areas. These soils are sandy in nature and contain calcium, but they are not high in nutrients. They do lack the heavy metals of serpentine soils, however. They almost always show a unique type of plant cover that is dominated by Chamise, a native shrub.
Vernal Pools
A vernal pool is a very shallow body of water that forms in a depression or low-lying area for a small part of the year. These temporary wetlands are common in the California chaparral and usually form in the spring, hence the seasonal reference within the name. Soils that are found underneath the pool are impervious to water penetration. This would include the soil types of hard pan, clay pan or volcanic basalt. Vernal pools are characterized by a luxurious spring growth of grass and wildflowers, such as lobelia, clover, daisies, wild mint and monkey flowers. These areas are usually lacking for shrubs or trees due to the hard pan underneath.
Gabbro Soils
Gabbro is an igneous rock that is sometimes worn down and uplifted to form a gabbro soil. This kind of soil is uncommon because the gabbro is usually formed beneath the earth's surface. However, California does support a gabbro soil in some chaparral areas. Gabbro soils are often red-tinted because of a high iron content and may contain higher concentrations of heavy metals such as chromium. Nonetheless, this soil type is nutrient poor and may support an unusual association of cover plants.
Alluvial Soils
Alluvial soils are created from the deposits made by rivers and streams. Alluvial soils tend to be richer in organic material and may have a higher concentration of loam or clay. Within the chaparral ecosystem, these soils usually are found along waterways and support a thick forest that may contain up to a half dozen different species of oaks. These soils can be found in the foothills of the Central Valley of California in places like Mount Diablo State Park.
Tags: Alluvial soils, chaparral areas, created from, earth surface, gabbro soil, heavy metals
