Floral associations are strongly correlated with latitude and altitude.
Much of northernmost Chile is utterly barren. Even in the river valleys that descend from the Andes, water usually reaches the ocean only during major floods, but subsurface aquifers support desert scrub and are even sufficient for irrigated agriculture.
One exception to the arid sterility of the lowlands is the Pampa del Tamarugal, a densely forested plain east of the city of Iquique. These woodlands of tamarugo (Prosopis chilensis), a relative of the common mesquite, are mostly plantations, but they represent the restoration of a native species that flourished on fossil Andean water before their deforestation for the colonial silver mining industry.
As rainfall increases with altitude and distance from the coast, the hillsides sprout stands of the appropriately named candelabra cactus, Browningia candelaris. Eventually, the cacti yield to several species of low-growing shrubs known collectively as tola but also stands of stunted queñoa (Polylepis tarapacana), one of the world’s highest-altitude trees.
The altiplano, also known as the puna, consists mostly of patchy perennial grasses interspersed with tola, though there are a few signature species such as the rock-hard llareta (Laretia compacta), a shrub so densely branched that it resembles a spreading moss. While the altiplano is mostly arid, it contains patches of well-watered marshlands known collectively as bofedales or ciénagas, which provide year-round pasture for domestic llamas, alpacas, and sheep. In some cases, indigenous pastoralists have created an ingenious system of canals to expand the area covered by bofedales.
Valdivian Cloud Forest
In scattered parts of the Norte Chico, drip from the camanchaca (coastal fog) supports a remarkably verdant forest flora whose closest geographical counterpart occurs in the well-watered Sur Chico. The best place to see this is Parque Nacional Bosque de Fray Jorge, west of the city of Ovalle.
From the Norte Chico through most of the Chilean heartland, the native flora consists mostly of sclerophyllous (glossy-leaved) shrubs that evolved to survive long dry summers. Their Northern Hemisphere analogue is the California chaparral.
Some southern beech (Nothofagus) species appear at higher elevations in the heartland coast range. The native palm Jubaea chilensis, once common here, is slowly declining, if not quite disappearing, because of overexploitation for economic ends.
Broadleaf and Coniferous Forest
South of the Río Biobío, various broad-leaved southern beeches, both evergreen and deciduous, are the most abundant trees. Several conifers also grow here, particularly the paraguas (umbrella) or monkey puzzle tree Araucaria araucana, so called because its crown resembles an umbrella and its limbs a monkey’s curled tail. The long-lived alerce or lawen (Fitzroya cupressoides) is an endangered species because of its high timber value, though most stands of the tree are now protected. Both the araucaria and the alerce are national monuments.
In western Chilean Patagonia, heavy rainfall supports dense and verdant coastal and upland southern beech forests, though there are many other broadleaf trees and even the occasional conifer such as the ciprés del los Guaitecas (Pilgerodendron uviferum, Guaytecas cypress). In some areas, though, this forest has suffered at the hands of corporations and colonists.
On the eastern plains of Magallanes, Tierra del Fuego, and parts of Aisén, in the rain shadow of the Andes, decreased rainfall supports extensive grasslands. In some areas, thorn scrub such as the fruit-bearing barberry calafate (Berberis buxifolia) is abundant. From the late 19th century, sheep grazing for wool had a tremendous detrimental impact on these natural pastures.
The Pacific Islands
While greatly transformed by the invasion of nonnative plants, the Juan Fernández archipelago exhibits such great floral diversity that it is a UNESCO World Biosphere Reserve. Easter Island (Rapa Nui), however, has a seriously impoverished flora partly because of its deforestation for rollers to move its famous stone monuments. The native tree toromiro (Sophora toromiro), for instance, no longer exists in its natural environment; efforts to reintroduce it from mainland botanical gardens have so far failed.
© Wayne Bernhardson from Moon Chile, 2nd edition