Terrestrial Biomes - Forests Chapter 6

Forests – Coniferous Taiga

Coniferous Forests Also called boreal forests or taiga –Also called the spruce-moose forest Found across the northern portion of N. America, Europe and Asia –Between the grasslands and the tundra No taiga in the Southern Hemisphere

Coniferous Forests Long, extremely cold winters with 6-8 hours of sunlight Short, cool summers with 19 hours of sunlight Annual precipitation (both rain and snow) 14-30”.

Coniferous Forests – Animals Populations are scarce, mostly herbivores –Large herbivores Reach high into trees or dig into deep snow –Seed eaters Pull seeds from cones Eat fallen seeds on the ground Carnivore size varies –Lynx, wolf

Coniferous Forest - Plants Primarily conifers –Also called evergreens –Stiff needles instead of leaves –Cones shaped seed cases Cones must open to release the seeds

Conifers - Facts Adaptations –Needles –Color –Shed their needles slowly –Decrease competition through chemical defense

Temperate Forests Deciduous

Temperate Forests - Facts Also called deciduous forests –drop leaves completely every winter Found in eastern N. America, western Europe and eastern Asia Long, very warm summers Cold winters (not severe) Forest soil is thick and very fertile

Deciduous Forest - Structure Stratified –Canopy –Understory –Shrub layer –Ground cover –Litter layer

Forest Structure

Deciduous Forest - Animals High biodiversity –Includes: Birds Small and large herbivores Small and large carnivores High degree of resource partitioning

Deciduous Forest - Plants High biodiversity from canopy to ground Canopy is primarily deciduous trees –Includes maples, birches and oaks

Plant Adaptations Leaves – broad and flat for maximum photosynthesis Excess carbohydrates made during photosynthesis is stored in the sap

Plant Adaptations Daylight shortens – Trees prepare to lose their leaves. –Chlorophyll is removed from the leaves –Tubes connecting the leaves to the stem close –Leaves begin to dry –Leaves fall – leaving only the branches exposed to winter snow, ice and wind

Plant Adaptations - Seeds Seeds can’t grow in shadow, so they must be dispersed. Done by: –Brightly colored fruit –Hard shells –Wings

Forests – Tropical Rainforest

Tropical Rainforests - Facts Found along or near the equator –Amazon River (S. America), Indonesia, Africa and Central America –Currently covers about 2% of the earth’s land surface –Believed to be the major source of the world’s fresh air

Tropical Rainforest - Climate Hot all year…very little variation in temperature No true seasons Humidity is always high Rains almost every day, usually in the afternoon. Annual precipitation – ”

Rainforest Structure –Similar structure as temperate forests plus the emergent layer –Canopy is very thick. Only 1% of sunlight ever reaches the forest floor.

Rainforest Animals Highest biodiversity in the world Contains at least ½ of the entire world’s plant and animal species Species are highly stratified. There is very little competition between species. Most animals live in the canopy because of the presence of sunlight.

Rainforest Animals

Rainforest Vegetation Trees are very tall (180’) with broad, evergreen leaves. –Mahogany Leaf cover is very dense, restricting growth of competing plants Roots are shallow to increase absorption of soil nutrients

Vegetation Adaptations Shallow tree roots are supported by buttresses. Understory plants have huge leaves to maximize sunlight for photosynthesis (elephant ear)

Specialized Rainforest Plants Epiphytes –Plants that grow on tree branches and trunks. –Roots absorb moisture directly from the air –Debris collects around their roots forming pockets of organic matter which they use as a nutrient source.

Specialized Rainforest Plants Lianas –Climbing vines –Roots are in the shallow soil, but the main plant is found in the canopy –Uses the trunks and branches of trees for support to reach the sunlight

Human Impacts on Forests Man is clearing the forests faster than the trees can regrow. Temperate forests are cleared in N. America, Europe and Asia for timber, cropland and urban development. Conifer forests in N. America, Canada and Russia are cleared for timber, mining and hydroelectric dams. Tropical rainforests are cleared for timber, domestic cattle and agriculture.

Human Impacts on Forests – Results Erosion increases Erosion causes suspended solids to increase in rivers and streams, killing aquatic life Agriculture in cleared soil rapidly depletes forest soil nutrients May lead to global warming May lead to overall loss of fresh air