4 September 2019
Mighty redwoods: The tallest trees on Earth
These resilient giants have fire resistant bark and live for thousands of years.
High and mighty
Kew Gardens and Wakehurst are home to incredible giants. We have a mixture of coastal redwoods (Sequoia sempervirens) and giant redwoods (Sequoiadendron giganteum) thriving in our gardens.
Our tallest tree in the whole of Kew Gardens is a coastal redwood. At 40 metres tall, it's as high as a 13 storey building.
In their native California, the humid summer fogs combined with winter rainfall allow redwoods to grow to immense heights.
Did you know?
The largest redwood in the world lives in Sequoia National Park, California. It stands at an incredible 84 metres tall and 11.1 metres wide.
Some coastal redwoods have been known to be as old as 2,200 years old, and giant redwoods can live to over 3,000 years.
One of the reasons redwoods live so long is due to a substance in their barks called tannin. This increases the tree's resistance to pests and diseases, and helps to deter insects like termites.
Redwoods have adapted to be fire resistant.
In their natural habitat, forest fires are common. These small frequent fires are called ‘cool’ fires. They clean the forest floor of dead leaves and branches but thankfully don’t destroy the trees.
Redwoods have thick, spongy bark which is around 12 centimetres thick and can reach 1.2 metres thick at the base of the tree. This helps to protect them from flames, along with the water-based sap they produce.
As redwoods grow, they lose their lower branches which stops fire spreading to the canopy. Coast redwoods also have the ability to re-sprout from their bases if the tree above is damaged by fire.
Although dangerous to us, fires are vital to a giant redwood forest. They leave behind ashes, which are the perfect fertiliser for redwood seeds to grow in.