Where are temperate deciduous woodlands found?
These woodlands are common in the mid-latitudes. Temperate deciduous woodlands are found between 40° and 60° north and south of the equator.
The rainfall is high, between 500-1,500 mm a year. The temperatures remain on average above 0°C even in the winter. The summer temperatures average between 20-25°C. The winter is cooler, which encourages the trees to shed their leaves.
What is the temperate deciduous woodland?
Deciduous woodlands contain trees with broad leaves such as oak, beech and elm. They occur in places with high rainfall, warm summers and cooler winters and lose their leaves in winter.
What is the structure of vegetation in the temperate deciduous woodland?
The image above shows a typical cross section in the temperate deciduous woodland.
The trees have typically large broad leaves, such as oak, beech and elm. These form the canopy layer.
As some light can get through, the vegetation is layered. The sub-canopy layer grows in spaces between the taller trees, where there is more water when it rains and more light. Beneath the sub-canopy trees is a shrub layer. The shrub layer contains species like hazel, ash and holly. Grass, bracken or bluebells can be found in the ground layer.
How did the temperate deciduous woodland get like this?
The rainfall is high, between 500-1,500 mm a year. The temperatures remain on average above 0°C even in the winter. The summer temperatures average between 25-20°C. The winter is cooler, encouraging the trees to shed their leaves.
The soil type is brown earth. This is a fertile soil. In the autumn the leaves fall from the trees. The leaves decompose and help to give the soil its nutrients. Earthworms in the soil help to mix the nutrients, and blend the layers within the soil.
The tree roots are deep and so help to break up the rock below. This helps to give the soil more minerals. The trees take up the nutrients in the soil as they grow. However, more nutrients are put back in the soil when the autumn comes.
How has vegetation adapted to the climate?
The Temperate Deciduous Forest biome has four seasons of winter, spring, summer and autumn. Plants have special adaptations to deal with these seasonal changes.
Deciduous are trees that shed their leaves at the approach of a cool or dry season and later grow new leaves. As temperatures drop, the tree cuts off the supply of water to the leaves and seals off the area between the leaf stem and the tree trunk. With limited sunlight and water, the leaves are unable to continue producing chlorophyll (green pigment in leaves) causing them to change into the beautiful red, yellow and orange leaf colours of autumn.
Leaves are shed as winter approaches due to unsuitable conditions for photosynthesis and possible water problems (lack of water as it is frozen in the earth). In winter, it is too cold for the trees to protect their leaves from freezing, so they simply loose them and seal up the places where the leaves attach to the branch. Losing their leaves helps trees to conserve water loss through transpiration.
Deciduous trees usually have broad leaves e.g., ash, beech, birch, maple and oak. Their broad, green leaves help capture sunlight needed to make food through photosynthesis. Before the leaves die, some of the food material they contain is drawn back into the twigs and branches where it is stored and used the following spring.
Bluebells grow very quickly in the spring so they can flower before the trees get their leaves as the forest floor is too dark to grow when the canopy is complete.
What is the impact of humans on the temperate deciduous woodland?
According to the Wildlife Trust there are approximately 240,000 hectares of lowland mixed deciduous woodland in the UK. However, this is only 1-2% of its original area and has declined 40% since 1935. This is the result of clearance for development and agriculture. Some ancient woodland was felled after the 2nd World War to provide building materials. This was replanted by the Forestry Commission, as conifer woodland, which has had a negative impact on wildlife.
What is the future for the temperate deciduous woodland? - Sustainable Development