Pygmy forest

Dwarf forest, elfin forest, or pygmy forest is a rare ecosystem featuring miniature trees, inhabited by small species of fauna such as rodents and lizards. They are usually located at high elevations, under conditions of sufficient air humidity but poor soil. There are two main dwarf forest ecosystem types, involving different species and environmental characteristics: coastal temperate and montane tropical regions. Temperate coastal dwarf forest is common for parts of Southern California. Montane tropical forests are found across tropical highlands of Central America, northern South America and Southeast Asia. There are also other isolated examples of dwarf forests scattered across the world. Dwarf forest, elfin forest, or pygmy forest is a rare ecosystem featuring miniature trees, inhabited by small species of fauna such as rodents and lizards. They are usually located at high elevations, under conditions of sufficient air humidity but poor soil. There are two main dwarf forest ecosystem types, involving different species and environmental characteristics: coastal temperate and montane tropical regions. Temperate coastal dwarf forest is common for parts of Southern California. Montane tropical forests are found across tropical highlands of Central America, northern South America and Southeast Asia. There are also other isolated examples of dwarf forests scattered across the world. Elfin forests of California are the primary example of coastal temperate dwarf forests. They are expansive, and cover most of the mountains in the southern half of California, extending into Mexico, Nevada, and Arizona. Other expanses of elfin forest are found throughout the state, in the northern and central regions. In northern California, Henry Cowell Redwoods State Park is home to an elfin forest with Mendocino cypress (Cupressus pigmaea), and Sargent's cypress (Cupressus sargentii), which is partially within a section of the Zayante Sandhill Area. On the Central Coast of California, on the southeastern shore of Morro Bay, Los Osos contains the El Moro Elfin Forest Natural Area. The area is approximately 90 acres. It derives the “elfin forest” title from the short California live oaks, which range in height from 4 – 20 feet, compared to the typical 30–80 feet. This region also contains the federally endangered Morro shoulderband snail (Helminthoglypta walkeriana). At a higher altitude, on Cuesta Ridge, the Land Conservancy of San Luis Obispo County manages the San Luis Obispo Elfin Forest of dwarf cypresses (Cupressus) Factors such as soil moisture, solar radiation, and rockiness of soil influence species composition along an elevational gradient, resulting in certain shrub species, such as Adenostoma fasciculatum and Arctostaphylos glauca, being present in elfin forest habitats. Fire occurs at low-moderate frequency with high severity. Many plants have adapted to this by having serotinous seeds that open to germinate only under high heat. Because of this, they are often the first to colonize a new area. Given that chaparral areas can be waterlogged in the winter, and arid and desert-like in the summer, native plants in these dry elfin forests have adapted accordingly, and are generally much shorter, smaller, and compact than related plants elsewhere. Diminutive plants commonly found in Californian elfin forests include Portulacaceae such as Mount Hood pussypaws (Cistanthe umbellata) and Alkali heath (Frankenia salina), and species of Aeonium and bird's-foot trefoil (Lotus). Trees and shrubs, such as chamise (Adenostoma fasciculatum), manzanita (Arctostaphylos), ceanothus, sumac (Rhus), sage (Salvia officinalis), and scrub-oak (Quercus berberidifolia) rarely grow more than 20 ft (7m) tall in these communities. Californian elfin forest fauna includes many species of deer mouse (Peromyscus spp.), harvest mouse (Reithrodontomys spp.), California vole (Microtus californicus), California pocket mouse (Chaetodipus californicus), kangaroo rat (Dipodomys spp.), and several species of spiny lizards (Sceloporus spp.), along with other small vertebrates. Invertebrates include the common scorpion (Scorpiones spp.), burrowing scorpion (Opistophthalmus spp.), and various species of spider (Araneae) and tick (Parasitiformes). The Californian climate usually exhibits wet winters and dry summers. Variation in these patterns can cause devastating damage to numerous plant communities. Plants found in elfin forests have adapted to grow during winter months, and become dormant during the summer due to drought stress. Plant communities deal with low, seasonal rainfall by relying on fog interception and taking in moisture from the air. Formation of coastal elfin forests in northern California and Oregon, began with a series of marine terraces. A combination of uplift and changes in ocean level formed a system of terraces, resulting in an “ecological staircase,” with each terrace approximately 100,000 years older than the one below it and supporting a distinct association of soils, microbes, plants, and animals. A dune being pushed farther away from the coast by fluctuating sea levels solidified and slid under the one before it, raising the terraces. Pioneer plant communities colonized and took over the young terrace. The succession of plant communities that repeated on each terrace eventually formed a very specific podzol known as the Blacklock series, which offers an inhospitable environment for species and greatly stunts further growth on the terrace. Part of this soil profile includes an underlying clay or iron hardpan. Each terrace is relatively level and many are footed by paleo-dunes. Drainage is poor at best on these stairs and plants sit in a bath of their own tannins and acids for much of the wet season. Plant communities on this terrace have reacted to limited root mobility and acidic soil by evolving stunted forms. Remnants of ecological staircases doubtless exist, however most have been destroyed for development or logging.