05.12.2023

Riddles & quizzes

Say, can you estimate the maximum age of the trees?

For International Volunteer Day, on December 5, and in anticipation of the Science Olympiads soon turning 20 years old, we've set you a little challenge: estimate the maximum age of a dozen hardwood trees in Switzerland. Now it's time to find out the answers.

Source: Illustration & Design © Iris Luckhaus

 

Keep in mind that trees rarely die of old age, but rather of disease, insect attack or felling. The timing of felling depends on the health of the tree and the silvicultural regime. Here's the list, in descending order:

1. Oak (pedunculate or white) 

Its maximum age is 900 years, with rare specimens reaching 1,200 years. Most, however, die at 500 years. This species of oak is most widespread at altitude, up to 1400 meters. The Bosses oak, in Châtillon (JU), is several hundred years old. 

2. Linden

Easily reaching 400 years old, it can live up 700 to 1000 years. Its maximum height is 40 meters, the average being 25 meters. This species is widespread in the Jura, Chablais and Ticino regions, particularly at altitudes of between 400 and 1100 meters. A specimen around 700 or 800 years old can be found in Linn (AR). 

3. Beech (common)

It can live up to 500 years, although most don't exceed 120 to 160 years. This species can be found at altitudes below 1,400 meters; it is most abundant east of the Jura mountains, especially around Liestal (BL) and Dornach (SO). 

4. Maple (sycamore) 

It reaches the venerable age of 500 years in primary forests, although its average age in Switzerland is between 80 and 100 years. It is widespread and very common in the Jura, the eastern Plateau and the Pre-Alps, at altitudes between 300 and 1,700 meters. Several giant specimens can be found on the mule track in Reichenbachtal (BE).

5. Hornbeam

Its maximum age is 350 years. Hornbeams are most common in northern Switzerland, at altitudes of between 400 and 900 metres. A monumental hornbeam can be found in the Parc de la Grange in Geneva (GE).

6. Ash (common) 

This species has a maximum age and height of 200-350 years. The highest proportion of ash is found on the Plateau and east of the Jura, but this species is widespread in the central Alps, up to an altitude of 1,500 meters.

7. Horse chestnut (common or white)

This species reaches a venerable age of 300 years. In most forests, however, the chestnut tree is no more than 120 years old. In Switzerland, its presence is strongest on the Plateau and in the Jura. The city of Geneva (GE) has an official chestnut tree since 1818, known as the marronnier de la Treille. When the first bud of the chestnut blossoms, spring is officially announced.

8. Alder (black) 

This species reaches a maximum age of 60-160 years. This tree is mainly found at low altitudes, on the Plateau and in Ticino. The Monod alder grove between Mollens and Pampigny (VD) is classified as a reserve of national importance.

9. Birch (warty or white)

This species can reach 150 years, but usually dies around 80. This tree is mainly found in the south of the Alps. Half of all warty birches grow above 990 m from sea level. In the central Alps, this species does not grow above an altitude of around 2000 m.

10. Aspen (common)

This species has a maximum life expectancy of 50-100 years. Other aspen species can reach 400 years. This tree is widespread in the cantons of Valais, Ticino and Graubünden, mainly at altitudes of 800 to 1,200 meters, but as a shrub up to 2,200 meters.

11. Hazel (Turkish)

It reaches 80 to 90 years old. This species grows as a tree and not as a shrub, unlike other hazel species (the common hazel, for example, reaches a maximum of 80 years). Turkish hazel is widespread in urban areas of the Plateau, thanks to its resistance to climatic hazards.

12. Willow (white) 

The willow lives 20-30 years. This tree is widespread in the cantons of Vaud, Valais and Ticino. It grows from the plains to altitudes of 1700 meters. 

 

How many did you get right?

Most of Switzerland's century-old trees are yew, larch and chestnut. The Swiss Federal Institute for Forest, Snow and Landscape Research (WSL-Junior 2011) estimates that the oldest yew trees today are between 1,000 and 1,500 years old. The WSL has been able to date the age of some larches at 800 years and estimates that the oldest specimens are in the canton of Valais. In Ticino, giant chestnut trees could be between 300 and 700 years old.

We thank Dr. Rita Bütler (WSL) for her clarification.

Sources

Bois Suisse (2023). "Essences de bous suisses" (online). URL link: https://www.holz-bois-legno.ch/fr/vivre-et-experimenter/la-foret-suisse/essences-de-bois-suisses (accessed on 28.11.2023)

Bütler, Rita, Markus Bolliger and Brigitte Commarmot (2015). "Die Suche nach altem Wald in der Schweiz" (online PDF). Schweiz. Z. Forstwes.166(2): 67-74. DOI: 10.3188/szf.2015.0067 (accessed on 27.11.2023)

European Commission, Joint Research Centre, Caudullo, G., De Rigo, D., Mauri, A. et al. (2016). "European atlas of forest tree species" , Caudullo, G.(editor), De Rigo, D.(editor), Mauri, A.(editor), Houston Durrant, T.(editor), San-Miguel-Ayanz, J.(editor). Publications Office of the European Union. URL link: https://forest.jrc.ec.europa.eu/en/european-atlas/ (accessed on 28.12.2023)

Institut fédéral de recherches sur la forêt, la neige et le paysage WSL (n.d.). "Âge biologique des arbres" (online). URL link: https://totholz.wsl.ch/fr/dynamique-forestiere/reserves-forestieres-naturelles-et-ilots-de-senescence/age-biologique-des-arbres/ (accessed on 23.11.2023)

Institut fédéral de recherches sur la forêt, la neige et le paysage WSL-Junior (2011). "Jusqu’à quel âge vivent les arbres en Suisse ?" (online article). URL link: https://www.wsl-junior.ch/fr/la-foret/cernes-et-croissance-des-arbres/jusqua-quel-age-vivent-les-arbres-en-suisse.html (accessed on 23.11.2023)

National Forest Inventory NFI (23.11.2023). "Tree species portraits" (online). URL link: https://www.lfi.ch/resultate/baumarten-en.php?lang=en​​​​​​​ (accessed on 27.11.2023)

Valforêt SA (n.d.). "Gestion sylvicole" (online). URL link: https://valforet.ch/gestion-sylvicole/ (accessed on 28.11.2023)

Waldwissen.net (n.d.). "Forest ecology: Forest plants" (online articles). URL link: https://www.waldwissen.net/en/forest-ecology/forest-plants/deciduous (accessed on 28.11.2023)

Woodland Trust (n.d.). "Species guides" (online). URL link:  https://ati.woodlandtrust.org.uk/how-to-record/species-guides/ (accessed on 04.12.2023)

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