Agriculture Reference
In-Depth Information
Sandy and Simpson (Australia) and Great Basin and Colorado (United States)
typically grow cacti and having < 250 mm of rainfall annually.
•
Alpine tundra
-subalpine forest occur near the north pole with winter 34°C and
summers 3-12°C being warm enough in the alpine tundra for plant growth such
as stunted plants like sedges, mosses and grasses when the surface layer of per-
mafrost melts, rainfall and snow 150 to 250 mm.
There are also mountainous zones such as the Andes and Himalayas and grasslands
steppes in Eurasia and across Russia, prairies of north America, pampas in south
America and savanna grasslands in northern Australia, and the veldt in South Africa
that complete the world bioms.
The diversity of habitats for plant growth is highest in the equatorial zones in
tropical rainforests (Schmitt et al.
2010
) and lowest in higher latitudes of the arctic
zones with most ornamental plants selected from tropical rainforest or cool temper-
ate zones. For instance, pines (
Pinus
spp.)
,
firs (
Abies
spp.) and spruces (
Picea
spp.) are selected from Europe and North America with the United States selling
25 million trees over the Christmas season and predicted to be sold for around
US$ 800 million in 2011 (Euteneuer and Campbell
2011
). These plants are well
suited to a cool temperate climate and are able to withstand cold winters. Also the
tropical poinsettia (
Euphorbia pulcherrima
) from Mexico and the South American
rainforest are extremely important potted plants, sold in Europe over the Christmas
season and as a garden plant in warm temperate regions.
Some notable examples of families of ornamentals that have been domesticated
and grown around the world are:
• China and SE Asia, Costa Rica, Guatemala, Mexico, Panama, Peru and Ecua-
dor feature hydrangeas (
Hydrangea
spp.); a popular ornamental plant with over
1,000 cultivars from 220 species originating mainly from Asia (China, Taiwan,
Japan, the Himalayas, and Indonesia).
• China, Colombia, Latin America and the Caribbean prefer the magnolia (
Mag-
nolia
spp.) with 245 species of which 48 % are in cultivation (Botanical Gardens
Conservation International
2008
). The cultivation of the magnolia appears to be
adapted to a narrow temperature range growing best below 18 ºC with growth
decreasing at higher temperatures (van Iersel and Lindstrom
1999
).
• Himalayas and SE Asia are largely responsible for the Rhododendron (
Rhodo-
dendron
spp.) with 1,157 species (Botanical Gardens Conservation International
(
2007
) that range from creeping plants to tall trees. The main centres of diversity
originate in the mountain ecosystems of North America, Himalaya, Myanmar,
Southern China and Europe, growing mainly on acidic soils in regions of high
rainfall, high humidity and a temperate climate. Some 25 % of species are under
threat (Gibbs et al.
2011
) including the scented tender Vireya type rhododen-
drons.
• USA with the honeysuckle (
Lonicera
spp.) from southern United States and
Mexico and the Chilean butterfly bush (Buddleia americana) from south eastern
United States to Chile.
