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taiga
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TAIGA
Geography
The taiga can be found in areas in the Northern Hemisphere
Largest vegetation on earth Taiga is the Russian word for forest Belt of coniferous forest Located in high latitudes of the northern
hemisphere Sunlight hits the surface of the earth and
scatters Results to large temperature differences as
seasons progresses Covers 11% of the earth’s terrestrial
surface
What is Ecotone?
An ecotone is a transition area between two biomes but different patches of the landscape, such as forest and grassland
4 major vegetation zones
Forest tundra ecotone Open stands of spruce lichens and moss
Open boreal woodland Lichens and black spruce
Main boreal forest Continuous strand of spruce Pines
Boreal mixed forest ecotone Boreal forest grades into mixed forest
Forest tundra ecotone
Open boreal woodland
Main boreal forest
Boreal mixed forest ecotone
CLIMATE
Summer
Strong seasonal variation Summers are short, cool and moist
(24-hr average temp is 10 °C or more) lasts 1–3 months and always less than 4 months.
Temperature range in the summer gets as low as -7° C (20° F).
The high in summer can be 21° C (70° F). The summers are mostly warm, rainy and humid.
Influenced by northern hemisphere location
Winter
Winters are prolonged, harsh and dry w/ long lasting snowfall The winter temperature range is -54 to -1°
C (-65 to 30° F).
Precipitation
The total precipitation in a year is 30 - 85 cm (12 - 33 in)
The forms the precipitation comes in are rain, snow and dew.
Most of the precipitation in the taiga falls as rain in the summer.
Permafrost
Perenially frozen subsurface that may be hundreds of meters deep
Upper layer thaw in summer Refreezes in winter
Develops when ground temp is below O˚C
Impervious to water Water remains and moves above it Ground thus stays soggy even though
precipitation is low This enables plants to exist
Accumulated organic matter protect the permafrost Shading and insulation
Reduces warming and retard thawing of the soil in summer
Soil
The type of soil is called Pozol are the typical soils of coniferous, or boreal
forests sandy and excessively drained poor soils for agriculture
Taiga soil tends to be young and poor in nutrients.
It lacks the deep, organically enriched profile present in temperate deciduous forests.
Since the soil is acidic due to the falling pine needles, the forest floor has only lichens and some mosses growing on it.
Effect of permafrost to soil
Vegetation and organic debris impede the thawing of the permafrost and act to conserve it
Permafrost chills the soil Retarding the growth of both above ground and
below ground parts of plants Limits activity of soil microorganisms Diminishes aeration and nutrient content of soil The colder the soil becomes, the closer to the
surface the permafrost moves, and the more shallow the soil becomes
The effect becomes more pronounced the closer the permafrost is to the surface of the soil
This contributes to the formation of shallow root systems by plants
This is in order to get more water from the surface
Lichens retain soil moisture through the growing season, encouraging the growth of trees on sites that would otherwise be too dry.
Decomposition
Decomposition
Because of cool temperatures decomposition is slow in the taiga.
Undecayed vegetation builds up on the forest floor, making it feel like a sponge.
Since decomposition is slow, the soil is thin and lacking in nutrients.
Trees grow taller where warmer temperatures allow for faster decomposition or by streams and rivers which carry nutrients from higher ground.
Fires
Fires are reoccurring events in the taiga During periods of drought, fires can
sweep over hundreds of thousands of hectares.
All boreal species, both broadleaf trees and conifers are well adapted to fire
Unless too severe, fire provides a seedbed for regeneration of trees
Biotic
The Taiga appears as an endless sweep of sameness – a blanket of spire-shaped evergreens over the landscape.
The boreal forest conifers fall into 3 growth forms (1) the spire-shaped spruces and fir.(2) The open, thin, light-penetrating upper
canopy of pines and (3) the deciduous larch.
Plants
Only a thick carpet of mosses grows in the dense shade of spruce, while lichens grow under pine.
Conifers are well suited to the cold taiga environment. The narrow, needlelike leaves with their thickened cuticles and sunken stomata reduce transpiration and assist in moisture conservation during periods of summer drought and winter freeze.
The dark green color of spruce and fir needles helps the foliage absorb maximum heat from the sun and begin photosynthesis as early as possible.
Conical shape - promotes shedding of snow and prevents loss of branches.
Evergreen habit - retention of foliage allows plants to photosynthesize as soon as temperatures permit in spring, rather than having to waste time in the short growing season merely growing leaves.
Black spruce (ability to tolerate wet soils and occupies cold, north-facing slopes and bottomlands)
White Spruce and Birch grow on permafrost-free south-facing slopes.
For some species, wildfires (with return times of between 20–200 years) are a necessary part of the life cycle in the taiga; some, e.g. Jack Pine have cones which only open to release their seed after a fire, dispersing their seeds onto the newly cleared ground.
AnimalsThe boreal forest, or taiga, supports a large range of animals.
Insects play a critical role as pollinators, decomposers, and as a part of the food web. Many nesting birds rely on them for food.
More than 300 species of birds have their nesting grounds in the taiga. Siberian Thrush, White-throated Sparrow, and Black-throated Green Warbler migrate to this habitat to take advantage of the long summer days and abundance of insects found around the numerous bogs and lakes.
BIRDS
Siberian Thrush
White-throated sparrow
Black-throated Green Warbler
Birds also feed and extract conifer seeds from cones, thus helping in the dispersal of seeds of trees.
The Taiga is home to a number of large Herbivorous mammals, such as moose and reindeer/caribou. Some areas of the more southern closed boreal forest also have populations of other deer species such as the elk (wapiti) and roe deer.
These Large herbivores of the boreal forests feed on grasses, sedges, and lichens.
Carnivores like wolves, lynx (bobcats), are also found in boreal forests
Adaptations of animals
Antlers of moose and deer are used in defense and fighting
Thick Fur help insulate the animals that live in taigas
Some animals have fur that help them blend in with the surroundings
Snowshoe hare
Others are agile and fast so that they can capture their prey.
Other animals, like wolves team up to take down larger prey.
Human Impact
Clear cutting has destroyed habitats of animals thus forcing them to leave
Hunting activities have affected the population of animals in the boreal forests. Making some of the animals threatened/ endagered.