What is a tree?
What is a tree?
Save our Trees Save our Planet.
Trees are the lungs of our planet, they give us oxygen, store carbon, stabilise the soil and give life to the world's wildlife.
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A tree is a tall plant with a trunk and branches made of wood.
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Trees can live for thousands of years; the oldest living tree is over 5,000 years old.
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They are the largest living organism on our planet, some grow to 100 metres high,
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They come in many different shapes and sizes, there are over 60,000 different species of trees on our planet.
Parts of the tree and their functions
Watch this Happy Learning video about trees.
Crown
The crown of a tree is all the branches, leaves, and reproductive structures extending from the trunk.
Branches
Branches are important to the tree because they play the role of structural support for the leaves, fruits and flowers that the tree produces. They are also the vessels that carry water from the soil to the leaves, and the food from the leaves to the rest of the tree.
Twigs
Twigs are small thin branches that grow out from the larger branches of a tree.
Twigs are very important because this is where the many buds are formed which produce the trees Foliage - its leaves, fruit, flowers or blossom, and seeds to produce more trees.
Foliage
A tree's foliage is its leaves, fruit, flowers, and seeds. It helps to keep the tree alive and to produce more trees.
Buds
Tiny leaves and sometimes flowers are located in packages called buds. In spring, sap rises from the roots to the branches; and the trees leaves and flowers unfurl and grow.
Flowers
The flowers are the reproductive part of the tree, they produce seeds, which then produce more trees. When the flower (or blossom) has been pollinated, it grows into fruit or berries ... if we cut open a fruit or berry, we will see the seeds inside.
Pollination
Before a flower can grow into a fruit or berry it must be pollinated. Pollination is the transfer of pollen from a male part of a plant to a female part of a plant, later enabling fertilisation and the production of seeds, most often by an animal, bird or insect or by the wind.
Watch this BBC Teach video about Pollination
Fruit
The main purpose of fruit is to protect seeds during development. They are also important for attracting birds and other animals to eat seeds.
Birds may carry seeds to a new location in their beaks or claws. A bird may be planning a meal or building a nest, and fly off with a seed or fruit to a safe area. Along the way, the bird may drop whole fruits or a few seeds, allowing them to reach new spots, far from the parent plants.
Seeds
A seed contains a miniature plant, called an embryo, that can develop into a fully grown plant. The outer shell of a seed, called a seed coat, protects the embryo. Inside the seed a nutritious material provides food to the embryo. In flowering plants this material is called endosperm.
Trunk
The trunk is the part of a tree that connects the leafy crown with its roots. Roots absorb water and nutrients from the soil, which are then transported up the tree trunk in cells in the Pith that act much like pipes. ... Food made in the leaves is then transported down to the roots and to other parts of the tree for growth. The wood in the trunk helps to support the tree and give it strength, whilst the bark protects the tree from harm and stops the water inside from escaping. Bark also protects the tree from injury by people, animals, and weather.
Roots
Roots are very important. They not only anchor the tree to the ground, but they also suck the water and nutrients up out of the soil and into the tree.
Roots are not only good for the tree; they are good for the soil. When it rains, the roots hold the soil in place so it is not washed away. When soil gets washed away it is called erosion.
Growth Ring
If you cut a tree trunk, the light spring wood and dark summer wood are clearly visible in bands around the tree. By counting each dark ring of summer wood you can find out how many growth cycles the tree had; giving you its age. These rings can also tell us what the weather was like during each year of the tree's life.
Pith
Pith is the tiny dark spot of spongy living cells right in the centre of the tree trunk. Essential nutrients are carried up through the pith to feed the tree.
Heartwood and Sapwood
The sapwood is dead and is the hardest wood of the tree. The heartwood is dark, and it helps to support and give the tree strength.
Leaves
During a process called photosynthesis, leaves turn light energy into food and air to help the tree stay healthy. Through pores or stomata, leaves breathe in carbon dioxide and breathe out oxygen. They also evaporate water back into the atmosphere.
Cambium
The cambium cell layer is the growing part of the trunk. It annually produces new bark and new wood.
Inner and Outer Bark
Bark helps to keep water in the tree from escaping. It also protects the tree from injury by people, animals, and weather.
The importance of trees
