Coniferous forest: Ample green zones among the mountains

Coniferous forests are found in Europe, Asia, North America, southeast South America, New Zealand and Tasmania. They are temperate areas with warm summers, cold winters and normal rainfall. Annually, around 500 mm of precipitation falls. 

Structurally, it is formed by two layers or stratums: the canopy (junction of the tree tops, which get together to form the roof of the forests) and the undergrowth (vegetation formed by grasses and bushes that grow beneath the trees). In some coniferous forests there is also an intermediate bushy layer.

The main arborous species are: pines, firs, larches, cypresses and birches. Pine forests (there are close to 150 varieties) grow in poor soils and house a herbaceous undergrowth dominated by perennial herbs. 

The structure of coniferous forests encapsulate three general forms of growth:

– Pines with straight, cylindrical trunks: branches that come out in whorls (group of three or more branches that are together in the same stalk) and density of its top that varies depending on the species. Dense tops include the Red Pine (Pinus resinosa) and the Lord Weymouth Pine (Pinus strobes); the Virginia Pine (Pinus virginiana), Scots or Wild Pine (Pinus sylvestris) and the Shore or Lodgepole Pine (Pinus contorta) have narrow, separated tops.

Cone-shaped evergreens: such as spruces, firs, and in some exceptional cases, cedars.

– Deciduous conifers: like larches and swamp cypresses (Taxodium distichum). It is worth pointing out that within coniferous forests there are three known types:

Montane forests

Many coniferous forests appear on the mountains and they are called montane forests. This type of coniferous forest develops in central Europe, where the Norway Spruce (Picea abies) is predominant, which covers from the mountain slopes to the sub-alpine mounts of the Carpathian Mountains and the Alps. In North America (territories of Canada and The United States) there are several areas of montane forests, among them, the Rocky Mountains, the Wasatch Range, Sierra Nevada and the Cascades. So, in southern Canada and northern United States montane forests appear between 1,700 and 3,500 masl, and in the southeast of the United States they develop between 2,500 and 4,200 masl.     

In the Rocky Mountains, where the winter is long and the snowstorms are intense, a sub-alpine forest grows that is characterized by the presence of the Engelmann Spruce (Picea engelmannii) and the Subalpine Fir (Abies lasiocarpa). The intermediate altitudes present great extensions of the Coast Douglas-Fir (Pseudotsuga menziesii) and low zones are dominated by open Ponderosa Pine (Pinus ponderosa) and Logepole or Shore pine forests.

In the Sierra Nevada and the Cascades there are similar forests and they are characterized for their great height. Among the species that make them up are: the Mountain Hemlock (Tsuga mertensiana), the Red Fir (Abies magnifica) and the Lodgepole or Shore Pine. Also found are the Sugar Pine (Pinus lambertiana), the California Incense Cedar (Calocedrus decurrens) and the greatest of all known trees, the Giant Sequoia (Sequoiadendron giganteum). 

Pinelands

They are vast forests made up of pines. They develop in Eurasia and North America.The Scots pine, an important component of the Eurasian boreal forest, is also widespread in central Europe, where it grows from the low lands to the beginning of the mountains. It also frequently appears in forests of the south of England and the west of France. Pine forests of the coastal plains (near the Atlantic) of the United States are considered the succession of the deciduous temperate forest. This way, in the far north of the country are the coastal pine lands of New Jersey, where the predominant species is the Maritime Pine (Pinus Pinaster). The following develop farther south, the Loblolly Pine (Pinus taeda), Longleaf Pine (Pinus australis) and the Slah Pine (Puns elliottii).

Rainy temperate forests

The rainy temperate forest and the northern boreal forest develop in southern Alaska, but they stand out for their composition and ecological characteristics. The reasons for these differences are climate and topography. The winds carrying humidity coming from the Pacific crash against the barrier of the coastal mountain range and rise abruptly. As it cools rapidly, the humidity of the air is released in the form of rain and snow (nearly 6,350 mm a year). In the summer, when the winds start coming from the northeast, the air cools down above the cold northern seas.

Although the rainfall is less, an intense mist is formed due to the fresh air. It sets on the leaves of the forests trees and falls to the ground, adding some 1,270 mm more of water. This way, the vegetation of the rainy temperate forest is characterized for being exuberant and for having humid temperate winters, hot dry summers and poor soil. The dominant species are the Western Hemlock (Tsuga heterophylla), the Mountain Hemlock, the Pacific Silver Fir (Abies amabilis) and the Coast Douglas Fir. The Red Sequoia (Sequoia sempervirens) forest grows farther south, where precipitation is lower

Fauna in the coniferous forest

It varies considerably depending on the nature of the vegetal association, meaning, the types of trees that are found in the forest. The invertebrate fauna present in the fallen leaves (group of leaves that have fallen from the trees) is dominated by mites, for example, the Southern Pine Beatle (Dendroctonus frontalis), which can turn into a plague for the southern pinelands. Regarding the birds that are closely associated to coniferous forests, there are several species. This way, in North America one can find the Great Tit, Goldcrests, Crossbills, the Purple Finch (Carpodacus purpureus), the Hermit Thrush (Catharus guttatus) and the Pine Siskin (Carduelis pinus). In the European forests, some species that are related to the North American ones are frequent, including tits and hawfinches. With the exception of the Marten and the Lynx (the latter is an endangered species), mammals have a lower affinity to coniferous forests than birds. Most of them develop in this type of forest, but also associated to others, like the deciduous ones. A few of them are the Virginia Deer (Odocoileus virginianus), the American Elk or Moose (Alces alces), the Brown to Black North American Bear (Euarctos americanus) and the Red Squirrel (Sciurus vulgaris)