02 Mar What Tree? Giant Sequoia
Giant Sequoia (Sequoiadendron giganteum)
As most of you will already know, this is one of the largest trees on the planet, with the oldest known sequoia being over 3,000 years old. The tree originates from the western side of America and mountain ranges of Sierra Nevada in California where trees are associated with natural groves which cover over 100km2.
There are differing interpretations of the origin of the name for this species. But generally, these link to the name originating from a man named Seqouyah, who grew up with the native Cherokee Indians and introduced the Cherokee alphabet. There are also links with the Latin sequi (meaning to follow) being associated with the mathematical sequence of seeds per cone. As a result of this coincidence between the languages the name ‘Sequoia’ was derived.
When the tree first arrived in the UK via William Lobb in 1853, it rested with the Horticultural Society to name the introduction. To commemorate the deceased Duke of Wellington, it was named ‘Wellingtonia gigantea’. With John Lindley of the Horticultural Society reportedly stating:
“As high as Wellington towers above his contemporaries, as high towers this California tree above the forest surrounding it. Therefore, it shall bear for all time to come the name Wellingtonia gigantea.”
Eventually the scientific name of Sequoia giganteum was settled on due to the tree’s botanical link to the California Redwood (Seqouia sempervirens) and dispute the name caused with American botanists. Many people in the UK still refer to this species as Wellingtonia, which links directly back to the first application of the name in the UK. This tree is also known as the giant redwood, Sierra redwood and Wellingtonia. It is classified in the same subfamily as coast redwood and dawn redwood.
It is listed as an endangered species, with fewer than 80,000 trees remaining. A significant proportion (approximately >12,000 trees) of the American population was reported as lost due to a forest fire in 2020.
Timber from these trees is generally brittle and therefore is not readily used in construction. Nevertheless, a large number of trees were felled for timber when the species was first discovered. The principal economic use for this species is from tourism, particularly the west coast of America, but also as popular features in parks and arboretums across the globe.
Due to its ultimate form and grandeur this is a popular species for planting in arboretums, parks and other publicly accessible areas. An avenue of over 200 trees were planted in 1865 near Camberley in Surrey and an avenue of over 50 trees planted in 1863 in botanic garden of Benmore in Scotland. These avenues highlight how ubiquitous the species choice was amongst Victorians.
Appearance and Identification
In maturity the tree is easily recognisable. Even in the UK, it is a very prominent tree of pyramidal/columnar form, often with low hanging branches that can rest on the ground in a sweeping form. Trees grow to an average height of 50-85m in their natural habitat. The tallest recorded tree exceeds 94m. Trunk diameters can be very sizeable with the largest recorded at nearly 9m. However in the UK, the largest recorded specimen is at Benmore in Scotland, with a height of over 56m.
The tree has fibrous, furrowed bark that can be over 50cm thick at the base of mature tree trunks.
Needles are evergreen, bluish green and 1-1.5cm long and arranged spirally on shoots. Shoots can feel sharp to the touch.
Cones are upright until they ripen after the second year, at which point they hang down. Cones can contain over 230 seeds. The cones have approximately 30-50 spirally arranged scales with several seeds per scale. Cones also open immediately after fire to capitalise on the natural clearing of competing vegetation, to enable seedling growth in direct sunlight.
Propagation and Control
Trees are generally disease and decay resistant due to the high level of tannic acid, which is contained within the trees sap. It is this acid which provides protection from forest fires too.
While the tree is relatively fire resistant, it remains one of the greatest threats to this species in its natural habitat. With a fire in 2020 reportedly destroying over 10% of the natural population. Coupled with the risk from fire is increased periods of drought, which have been exacerbated in recent years due to the increased impacts of climate change.
This species is tolerant of a range of temperatures and soil ranges and grows well across the UK and much of Europe. The tree thrives on well-drained, nutrient rich soils. While the tree is resistant to wind, reports indicate it can suffer from windburn in particularly exposed and hostile environments.
Source and Reference Materials
Information detailed in this post has been obtained from the author’s own knowledge and photographic library where possible. Additional source of information and photographs include:
More, D & White, J. (2013). Illustrated trees of Britain and Europe. Domino.
Van den Berk, B.V. (2004). Van den Berk on Trees. Van den Berk Nurseries
Images