Common names: Giant Sequoia, Wellingtonia, Redwood 

Irish name: Mórghiúis dhúdach 

Latin name: Sequoiadendron giganteum 

Family: Taxodiaceae 

Origin: Non native 

Tree type: Evergreen conifer

How it looks

Shape, bark, twigs 

Giant Sequoia are very large fast growing evergreen conifers. In fact they are the largest trees in the world (in terms of mass). They have a huge red trunk and pyramid shaped crown. The tree has very thick bark which is reddish in colour and soft and spongy to the touch. The bark can be up to 30cm thick on mature trees. As the tree matures, the lower stem becomes free of branches.  

Leaves 

The leaves are grey, small and scale up to 1cm. They are sharp and pointy and coat the downward hanging shoots.  

Flowers 

The male cones are small, about 2-3 cm long, and produce pollen, while the female cones are initially green and resemble tiny artichokes. As they mature, they become woody and brown, and can remain on the tree for up to 20 years, until they dry out and release the seeds which resemble the size of an oat flake.

Similar species 

Very like the Coastal redwood (Sequoia sempervirens), which are the tallest living trees.

Where to find it

It is native to the Sierra Nevada area of California. Despite having only being introduced here about 160 years ago, Giant Sequoias grow very well in Ireland and the UK, liking our mild maritime climate. Growth rates of young trees have been higher than those in their native California.

Cultural importance

The giant sequoia is native to California in the United States and has had great cultural significance for the Indigenous peoples who have lived in this region across millennia. For instance, the creation stories of the Southern Pomo and Coast Miwok First Nations relate that Coyote created the world from the top of Sonoma Mountain and that his village elders were the redwoods or giant sequoias. Similarly, Yurok First Nation stories consider these huge trees as sacred, living beings. 

For hundreds of years these First Peoples used fallen wood from the giant sequoias to build their houses, canoes and sweathouses. It was also used to create finer objects such as baskets, platters, storage chests and sculptures, while the leaves were used to make poultices for healing earaches. These communities revered the giant sequoia as a spiritual being and believed that the objects which they made from its wood carried the spiritual energy of the tree. Indeed, in one Yurok creation story, the giant sequoia is said to have instructed the community how to make canoes from its wood. 

With the advent of the goldrush in the 1850s, greater numbers of Euro-American settlers moved into the region, displacing the Indigenous communities from their ancestral territory. It was during this time that settlers became aware of the giant sequoia trees, which they proceeded to cut down in vast numbers for timber. By the end of the nineteenth century, people feared that the giant sequoias would become extinct. Thankfully, around this time, the conservation movement came into being and two National Parks were created to protect the giant sequoias that can be seen there today. 

While the giant sequoia is native to California, fossil evidence discovered in County Galway suggests that it was once native to Ireland around the beginning of the Pleistocene epoch, approximately 2.58 million years ago. It was reintroduced to Ireland in the 1850s and became very popular with members of the landed gentry, like Viscount Powerscourt, who planted them on their estates. Mature examples can still be found throughout the country. Giant sequoias were also popular with botanists including those at University College Cork, where three beautiful examples still stand. More recently, the Earl of Rosse has launched a project in partnership with the charity Crann to plant in Birr, County Offaly, the largest grove of giant sequoias outside of California. For further information see https://giantsgrove.ie/ 

Value to wildlife

Giant Sequoias offer vital habitats for many different wildlife species. Their towering branches serve as nesting grounds for birds, while the tree's crevices and bark offer refuge to various animals, including squirrels, owls, and bats.

Sequoias and fire

Fire is very important in the ecosystem of Sequoias. Giant sequoia cones are serotinous, which means they open and release seeds when exposed to fire on the forest floor. This timing helps ensure that most seeds are released when conditions are best for new growth after a fire. Fires also clear away debris and expose soil, while the ash adds nutrients and increases sunlight by clearing competing trees. With their thick bark, giant sequoias are well-protected and insulated from fire damage. Their bark contains tannins that fight off pests and diseases, making them tough and able to live for thousands of years—the oldest known giant sequoia lived for 3,200 years. In the past, low to moderate fires, often started by lightning or Indigenous communities, were a regular part of the forest's life. These fires cleared out smaller trees and debris, making huge fires less common.

Threats

Although severe wildfires have become a concern for giant sequoias in recent times, prescribed burning continues to be a crucial management strategy. It helps decrease fuel levels in sequoia groves, promotes the growth of young sequoias, and enhances the resilience of these groves to climate change and wildfires. 

Other threats include drought conditions in their native range. This has led to acute foliage dieback. They are also susceptible to attacks from bark beetle.

Uses

Giant sequoia is planted as an ornamental tree both inside and outside of its native range. It is also used as a Christmas tree.

References

Crann. 2024. Giant’s Grove Project, Crann. Giants Grove Project | Crann - Trees for Ireland

George, Z. 2018. How California’s Giant Sequoias Tell the Story of Americans’ Conflicted Relationship With Nature, Smithsonian Magazine. How California's Giant Sequoias Tell the Story of Americans' Conflicted Relationship With Nature | Science| Smithsonian Magazine

Humboldt Redwoods Project. 2024. Indigenous Use of Redwood, Humboldt Redwoods Project. Indigenous Use of Redwood · Redwood as Object · (omeka.net) 

Nova, A. 2013. From the Redwoods to Redwood, Better Farm Blog. From the Redwoods to Redwood — Better Farm 

Trinity College Dublin. 2024. Trinity Tree of the month - the Giant Redwood, Trinity College Dublin. Trinity Tree of the month - the Giant Redwood - News & Events | Trinity College Dublin (tcd.ie) 

Viloria, D. 2018. The Ancient Ones: Redwoods Through the Eyes of a Southern Pomo and Coast Miwok Native, Save the Redwoods League. The Ancient Ones: Redwoods Through the Eyes of a Southern Pomo and Coast Miwok Native - Save the Redwoods League 

Viney, M. 2021. Another Life: A giant redwood can remove a lifetime of carbon from the atmosphere, Irish Times, October 2, 2021. Another Life: A giant redwood can remove a lifetime of carbon from the atmosphere – The Irish Times 

Woodstock Gardens and Arboretum. 2024. Giant Redwood (Sequoiadendron giganteum), Woodstock Gardens and Arboretum. Giant Redwood (Sequoiadendron giganteum) - Woodstock House & Gardens