Vegetation

Fig: 120 from CPHG book 

In physical geography, a tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. Tundra means a treeless mountain tract.

There are three (3) types of tundra: 

1. Arctic tundra
2. Alpine tundra
3. Antarctic tundra

In a tundra, the vegetation is composed of dwarf shrubs, sedges and grasses,mosses, and lichens. Scattered trees grow in some tundras. 

• Arctic tundra occurs in the far Northern Hemisphere, north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost, or permanently frozen soil.
• Antarctic tundra occurs on Antarctica and on several Antarctic and sub antarctic islands, including South Georgia and the South Sandwich Islands and the Kerguelen Islands. 
• Alpine tundra does not contain trees because the climate and soils at high altitude block tree growth. Alpine tundra is distinguished from arctic tundra in that alpine tundra typically does not have permafrost, and alpine soils are generally better drained than arctic soils.

Deciduous Forests:- 

In a more general sense, deciduous means "the dropping of a part that is no longer needed" or "falling away after its purpose is finished". In plants it is the result of natural processes. In botany and horticulture, deciduous plants,including trees, shrubs and herbaceous  perennials, are those that lose all of their leaves for part of the year.

Two distinctive types of deciduous forest are found growing around the world.

• Temperate deciduous forest biomes are plant communities distributed in North and South America, Asia, Southern slopes of the Himalayas, Europe and for cultivation purposes in Oceania. They have formed under climatic conditions which have great seasonable temperature variability with growth occurring during warm summers and leaf drop in autumn and dormancy during cold winters. These seasonally distinctive communities have diverse life forms that are impacted greatly by the seasonality of their climate, mainly temperature and precipitation rates. These varying and regionally different ecological conditions produce distinctive forest plant communities in different regions.
• Tropical and subtropical deciduous forest biomes have developed in response not to seasonal temperature variations but to seasonal rainfall patterns. During prolonged dry periods the foliage is dropped to conserve water and prevent death from drought. Leaf drop is not seasonally dependent as it is in temperate climates, and can occur any time of year and varies by region of the world. Even within a small local area there can be variations in the timing and duration of leaf drop; different sides of the same mountain and areas that have high water tables or areas along streams and rivers can produce a patchwork of leafy and leafless trees.

Temperate coniferous forest:- is a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest. In most temperate coniferous forests, evergreen conifers predominate, while some are a mix of conifers and broad leaf evergreen trees and/or broad leaf deciduous trees. Temperate evergreen forests are common in the coastal areas of regions that have mild winters and heavy rainfall, or inland in drier climates or mountain areas. Coniferous forests can be found in the United States, Canada, Europe, and Asia.