The Giant Sequoia in the Parc de Woluwe

This conifer is one of the Belgian all-stars. To see it in its entirety, you would have to step back at least 40 metres. It would take seven or eight adults holding hands to reach around its trunk. Revered by the Native Americans of the Sierra Nevada (California, USA) this reddish-hued ‘mammoth’ tree is a calming presence. Its soft surface beckons to be touched, to discover its wonders and feel the strength it holds within, to listen to nature. The towering giant sequoia makes us all children again.

Emblem of the Region

Its imposing silhouette, with its tall, conical crown rises from one of the hillsides of the Parc de Woluwe. This English landscape park was designed at the order of Leopold II on the occasion of the Universal Exposition. Between 1896 and 1899, the architect Emile Lainé sculpted a wholly new landscape: ponds, woods, hills rising 30 metres high and wide, curving alleys were all created from scratch.

It’s the perfect environment for this sequoia, which has flourished here. In the wet meadow at the bottom of the valley, its roots find plenty of water. Its leaves absorb and store moisture from the mists. Its position on the hillside at the edge of a wooded area allows maximum exposure to the light of the rising sun for its foliage, which stays deep green and dense year-round.

Getting to know this bigger than life personality

Gently approach this colossus to stroke its bark. It is extremely thick (< 50 cm) spongy and fibrous: springy as a pillow, soft as velvet. Its reddish-brown colour gave rise to the popular name for the sequoia in America: the ‘redwoods’. Look closely at the foliage: it is made up of a multitude of small, pointed scales that grow along a stem and then spread out on the outer half. The tree also produces cones. They are green on the branches, but brown on the ground around your feet. They are egg-shaped, with flattened diamond-shaped scales that are slightly indented at the centre. They protect the tiny seeds: precious treasures of nature.

The genius of this tree

The minute seed that produced this mammoth tree came either from a Californian forest or an arboretum that was able to successfully reproduce redwoods. Starting from 1853, the Sequoidendron giganteum became a fashionable fixture of the parks of large estates and botanical gardens in Europe. Their seeds fetched a high price because they were found only in the Sierra Nevada in California, the only region in the world where redwoods grow naturally.

These Californian conifers reproduce in a surprising way. The cones must be subjected to intense heat to allow them to open and release their seeds. Without these conditions, they can stay closed and attached to their branches for 20 years. Forest fires are a great ally of the redwoods. They clear the forest floor and enrich it with their ashes: thus allowing the seeds to germinate. This alliance with fire is possible thanks to the bark of the redwoods, which is full of water and tannins, making it exceptionally fire resistant.

Each tiny seed contains all the information necessary to shape the vertical growth of thousands of cubic metres of wood into trees of dizzying heights that are able to live up to 2,000 years. The roots seem ridiculously small for the job of anchoring such a massive trunk. They do not penetrate very deeply into the ground at all. And yet, they manage to hold up trees that are 50 to 100 metres tall because they spread 30-40 metres in all directions.

275 million years of History

Sequoias have been on Earth since well before the dinosaurs. They were especially widespread in the Europe and North America between 65 and 24 million years ago. They gradually disappeared as a result of cold and drought before being completely eliminated from our continent by an Ice Age some 15 million years ago. Only two species, the giganteum, and the sempervirens, survive to this day in California. There, you will still find many specimens that once lived in harmony with the Native Americans before the arrival of Europeans.

For several centuries, the tribes of the Sierra Nevada coexisted peacefully with the redwood forests. They sometimes lived inside the natural cavities of the trunks. They understood the trees’ resistance to decay, parasites, and especially fire. They used strips of bark to build their huts and made nets and baskets with their fibres. Unlike the white men, the Indians did not cut down the redwoods, as they believed it would bring bad luck. They used the trees that the forests gave them.

European colonists only discovered the redwood forests in 1852. They attempted to exploit them intensively, but had to give up on harvesting them on a massive scale, as the forests of the Sierra Nevada were difficult to access and the quality of the wood from the giant sequoias was not sufficient to put it to profitable industrial use.

And then, the extraordinary nature of these trees was also responsible for saving a large area of the forest. The ‘big trees’ have become very popular tourist attractions. The oldest national parks in America are dedicated to them. Today, they are a protected species: they are part of the natural and historical heritage of the United States. Nevertheless, in 2017, the Trump administration questioned the protection of the Giant Sequoia National Monument. The American public, which has been mobilised several times in the past to protect them, is again on the alert.

The European redwoods have a quieter history. They were reintroduced in Europe in 1853 as ornamental trees, becoming a standard in parks. There are almost a thousand of them in Belgium. For now, they tend to be rather pampered. But who knows whether this attention will be enough to stand up to the blight (Botryosphaeria dothidea) that is ravaging the species, and to withstand climate change. They will need to be given even greater care: providing them with a constant supply of water, and allowing them light and a soil that is as rich as in the forests in which they are supposed to grow. Under these favourable conditions, like some of their American cousins, they can live for two centuries.

For more information: http://www.sequoias.eu (thanks to Marc Meyer who gave us a series of details about this fascinating species).

(Textes et photos par Priscille Cazin https://www.sylvolutions.eu)

This portrait is enriched with an illustration from the Belgian Federal State Collection on permanent loan to the Meise Botanical Garden. See attached. Thanks to the library (heritage collection) for this contribution. https://www.plantentuinmeise.be/en/home/