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
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 Waterremains 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
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 Vegetationand 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 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 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
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.
Only a thick carpet of mossesgrows in the dense shade ofspruce, while lichens growunder pine.
Conifers are well suited tothe cold taiga environment.The narrow, needlelike leaveswith their thickened cuticlesand sunken stomata reducetranspiration and assist inmoisture conservation duringperiods of summer droughtand winter freeze.
The dark green color of spruceand fir needles helps thefoliage absorb maximum heatfrom the sun and beginphotosynthesis as early aspossible.Conical shape - promotes shedding ofsnow and prevents loss of branches.Evergreen habit - retention of foliageallows plants to photosynthesize as soonas temperatures permit in spring, ratherthan having to waste time in the shortgrowing season merely growing leaves.
Black spruce (ability to tolerate wet soils and occupies cold, north-facing slopes and bottomlands)White Spruce and Birchgrow on permafrost-freesouth-facing slopes.
For some species, wildfires (with returntimes of between 20–200 years) are anecessary part of the life cycle in thetaiga; some, e.g. Jack Pine have coneswhich only open to release their seedafter a fire, dispersing their seeds ontothe newly cleared ground.
The boreal forest, or taiga,supports a large range ofanimals.
Insects play a critical role as pollinators, decomposers, and as a part of the food web. Many nesting birds rely on them for food.BIRDS 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.
Siberian Thrush Black-throated Green Warbler White-throated sparrow
Birds also feed and extract coniferseeds from cones, thus helping inthe dispersal of seeds of trees.
The Taiga is home to a number oflarge Herbivorous mammals, suchas moose and reindeer/caribou. Some areas of the moresouthern closed boreal forest also have populations of otherdeer species such as the elk (wapiti) and roe deer.
These Large herbivores of theboreal forests feed ongrasses, sedges, and lichens.
Carnivores like wolves, lynx(bobcats), are also found inboreal forests
Antlers of moose and deer areused in defense and fighting
Thick Fur help insulate theanimals that live in taigas
Some animals have fur that help them blend in with the surroundingsSnowshoe hare
Others are agile and fast sothat they can capture theirprey.
Other animals, like wolvesteam up to take down largerprey.
Clear cutting has destroyedhabitats of animals thusforcing them to leave
Hunting activities haveaffected the population ofanimals in the boreal forests.Making some of the animalsthreatened/ endagered.