You probably see hundreds of different trees every day, but when did you last stop to think about how each tree survives and flourishes? Here’s a quick rundown of the parts of a tree, and the role they play in ensuring healthy growth. 

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The crown

The crown of the tree includes its leaves and branches - the green ‘canopy’ of the tree. 

The branches carry nutrients from the trunk to the leaves, store unused food, and provide a support structure for the tree’s leaves, seeds, and fruit.

The leaves (or needles, for coniferous trees) create glucose through a process called photosynthesis. In simple terms, the leaves use energy from the sun to combine water (transported up from the tree roots) with carbon dioxide (absorbed from the air). 

This process turns the water into oxygen, which is released into the air, and the carbon dioxide into glucose, which is transported and stored in the tree trunk and roots.

That’s why maple syrup has such a sweet flavour; it’s made from the glucose-rich sap stored in the trunk of the maple tree!

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The trunk

Tree trunks have five distinct layers, each with a very different - but equally important - role to play in the tree’s growth and survival.

The outer bark is the tree’s armour, providing a protective layer against fungus, insects, and colder temperatures. Inside the outer bark is the phloem, a hard-working pipeline that transports glucose from the leaves to the other parts of the tree. As the phloem ages, it hardens and turns into outer bark.

The next layer is the cambium cell layer. This is where the magic happens! The cambium cell layer uses nutrients delivered by the phloem and sapwood to grow outwards. 

The sapwood is the next layer in from the cambium cell layer, and - like the phloem - it’s also a critical pipeline. Sapwood moves water up through the tree from the roots, ensuring that the leaves have the water they need to photosynthesise.

The innermost layer of the tree is heartwood; incredibly strong, inactive tree tissue that provides structural support. The heartwood is often used for woodworking and construction, because it’s far stronger than sapwood, and less likely to shrink and crack over time.

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The roots

One of the most common misconceptions about trees is that their roots always go deep, deep underground; in fact, most of a tree’s root system is in the top few few inches of the soil! 

Tree roots can spread far beyond the canopy, and often occupy an area 2-4 times the size of the crown. It’s worth remembering this when you’re applying herbicides or fertilisers to the rest of your property, as there could be hidden root systems below the surface.