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.