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Tropical Rainforest • • • • Located around the Equatorial regions Hot temperatures and rain year round No seasons Convectional rainfall Layers • • • Emergent Layer giant trees thrust above the dense canopy layer and have huge mushroom-shaped crowns. These trees enjoy the greatest amount of sunlight but also must endure high temperatures, low humidity and strong winds. Canopy Layer The broad, irregular crowns of these trees form a tight, continuous canopy 30 to 50 m above the ground. The branches are often densely covered with other plants (epiphytes) and tied together with vines (lianas). Understory: Dark, relatively open and contains young trees and leafy herbaceous plants that tolerate low light. Forest Floor The forest floor receives less than 2% of the sunlight and consequently, little grows here except plants adapted to very low light. On the floor is a thin layer of fallen leaves, seeds, fruits and branches that very quickly decomposes. Only a thin layer of decaying organic matter is found, unlike temperate forests. • Tress buttressed at the base • Leaves large • Thousands of species but individual species spaced widely apart • Nutrients are in the biomass not the soil • Nutrient Recycling Constant warmth and moisture promote rapid decay of organic matter. When a tree dies in the rain forest, living organisms quickly absorb the nutrients before they have a chance to be washed away. • When tropical forests are cut and burned, heavy rains can quickly wash the released nutrients away, leaving the soil even more impoverished. • Vegetation protects the soil. • Through the nutrient cycle, vegetation helps to maintain the soil fertility • When it rains, nutrient entre the soil • Plant roots quickly absorb the dissolved nutrients • Small organism eat leaves and litter • The rain forests are home to half of the Earth's plant and animal species. • They are winter homes to many birds that breed in temperate latitudes. • home to tribal cultures that have survived • The forests are a potential source of medicinal plants that may benefit everyone on Earth. • Tropical rain forests help maintain global rain and weather patterns. • The rainforest contains more than half of Earth's plant and animal species, even though rain forests cover only about 6% of the earth's surface. • The average humidity in the rainforest is high, ranging from 77% to 88%. The average temperature is at least 28 to 35 degrees. Tropical Monsoon • Less precipitation and dry season • Lush vegetation but more open and lose leaves in the dry season • Growth not as great and fewer species • Mesotherms adjust to moderate heat • Many lianas (woody vines) and herbaceous epiphytes (air plants, such as orchids are present. • Monsoon forests are especially well developed in Southeast Asia and are typified by tall teak trees and thickets of bamboo. Tropical Savannah • Grasses • Parkland • Wet/dry seasons Tundra • Long cold winters and short summers • Permafrost • Cold climate leads to short growing season • Soil is poor in nutrients • An under-layer of soil called permafrost remains completely frozen at all times allows no room for deep rooting plants and trees. This also prevents water from percolating into the ground and as a result, bogs, ponds and small lakes cover the landscape providing a perfect breeding ground for mosquitoes and other insects. • This abundant food brings many waterfowl to nesting grounds in the tundra. • Plants are extremely resilient with short, shallow roots close to the surface,adapt to wet soil in the short summer • Plant life consists of shrubbery, lichen, and moss. No trees! Taiga, Boreal Forest • Taiga is also know as Coniferous or Boreal Forest. • Largest terrestrial biome on earth which includes a variety of climate conditions, from moderate to severe. • Generally, winters are long and cold, and summers are mild and short. • Precipitation is moderate (20 to 60 cm) and evaporation is low. • Soils are thin, nutrient poor and acidic • Trees adapt by producing a dense network of shallow roots, grow small needle shaped, wax coated leaves, shed their needles • In the summer the soil is often waterlogged, forming acidic bogs (muskegs) • Dominated by black spruce, fir, pine, poplar, and aspen. Temperate Rainforest • Temperate rainforests are among the rarest ecosystems in the world, and originally comprised less than .02 per cent of Earth's land surface. • Approximately half of all original temperate rainforests have been logged. • Also called Coniferous Evergreen Forest • • temperate rainforests are found in the middle latitudes. Where milder climates prevail, deciduous tree species dominate, while coniferous tree species prevail where colder winters occur. Favorable growing conditions - a moderate climate, minimal changes in the seasons, and ample rainfall allow trees to grow all year in temperate rainforests. Trees are often enormous.. For example, in Washington State's Olympic Peninsula, a 127-metre (420 foot) Douglas fir was chopped down in 1895. Redwoods dominated California's temperate rainforests, and this fir tree was taller than a modern-day Redwood by 18 metres (60 feet). Sitka spruce, cedar and hemlock, fir are typical trees found in this biome. • • • • • • Coastal temperate rainforests have four defining characteristics: a proximity to oceans, presence of coastal mountains, cooler summer temperatures and high rainfall levels One of the most fascinating aspects of the coastal temperate rainforest is the blurred boundary between terrestrial and marine ecosystems. These forests have abundant epiphytes (plants that live on other plants); and they have a dense shrubby understory, even the surfaces of trees support other plants and lichens. Conifers have adapted to poor,acidic soil by developing a root systems which picks up nourishment from the top soil layer Trees cone shape with thin flexible branches so snow will fall off easily and strong winds will not break branches. Cones protect seeds from cold winter weather and waxy needles minimize water loss through transpiration in the summer. • • • • • Problems: Clear Cutting Logging Salmon at risk Species depletion Temperate Deciduous Forest Found in the mid-latitudes Characteristics of this biome influenced by patterns of temperature and precipitation. There are four definite seasons. During the fall, trees change color and then lose their leaves. This is in preparation for the winter season which is cold. Trees have adapted to the winter by going into a period of dormancy or sleep. They also have thick bark to protect them from the cold weather. Trees flower and grow during the spring and summer growing season. Many different kinds of trees, shrubs, and herbs grow in deciduous forests. Most of the trees are broadleaf trees such as oak, maple, beech, hickory,aspen and chestnut. There are also several different kinds of plants like mountain laurel, azaleas and mosses that live on the shady forest floor where only small amounts of sunlight get through. Leaf litter adds nutrients to the soil annually and enjoyed by the bugs. Mid-Latitude Grassland Steppe, Prairie • Grassland biomes are large, rolling terrains of grasses, flowers and herbs. • Latitude, soil and local climates for the most part determine what kinds of plants grow in a particular grassland. • A grassland is a region where the average annual precipitation is great enough to support grasses, and in some areas a few trees. The precipitation is so erratic that drought and fire prevent large forests from growing. Grasses can survive fires because they grow from the bottom instead of the top. Their stems can grow again after being burned off. • Grasses can be tall (1.5m) or short. Species distribution depends on moisture availability and heat. Mediterranean, Schlerophyll • • • • This subtropical Mediterranean biome is composed of small scattered trees (often less than 3m high),thorny bushes and shrubs. Also called the Maquis in Europe or Chaparral in California. Cactus and other water storing plants do well in this environment. The cacti often form dense thickets. The climate in this area is unique with the wet season occurring in winter and summer drought (annual rainfall of 15-40 inches) Olive Broom • • • Most of the plant growth is leafy, leathery and relatively short. It is important for plants to be drought resistant, to survive the short wet winters and long dry summers. Plants often have deep roots to tap water, but also help stabilize the soil during the brief rainy season. The geography of this region begins at the seashore and extends through rolling farmlands, with grazing and cultivation, into the mountains Fire is a major factor in the dynamics of this plant community, and plants are adapted to fire, ie. Crown-sprouting shrubs,and annual fire-followers. Important as fire thins out the vegetation. Extreme heat needed to develop some varieties of seeds. Deserts • Deserts cover about 1/5 of the planet • Deserts found in most latitudes • Evaporation exceeds precipitation, often rain evaporates before it hits the ground Desert Adaptations • Soil coarse, sandy • Vegetation limited but specialized • Plants are short, spaced widely apart, leaves are small, roots can be long (tap root) • Some xerophytic plants have extensive root systems to capture moisture in the soil. • Others have waxy leaves or fleshy tissues to store moisture. Enlarged green stems like those found on cacti take over the function of leaves in photosynthesis. • Some desert vegetation may shed parts of branches during extreme drought. • Thorns for protection