Sycamore (Acer pseudoplatanus) – Tree of the Year 2009

Sycamore is indigenous to Central and Southern Europe and can be found mostly in mountainous regions in mixed stands with beech, fir and spruce. Thus it is found up to 900m in low mountain ranges such as the Harz and Erz Mountains, and up to 2000m in the Central and Eastern Alps – i.e. it can tolerate greater altitude than most other deciduous tree species. After its cultivation in the 15th century, sycamore soon spread all over England and Ireland without any further human intervention. This is called invasion potential by botanists – though the sycamore is less invasive than Norway maple.

Its frequency and dominance becomes more obvious with increasing altitude (which is why it is called “Berg-Ahorn”, mountain maple in German. It prefers steep slopes, screes and humid valleys – remarkably beautiful are the Sycamore-Ash woods that can be found in canyons. These high-performance forests with excellent growth rates remind of tropical highland rainforests since the trees are abundantly covered with moss and lichen.
Provided that the climate is not too dry, sycamore belongs to the species most suitable for avenue cultivation. Where shadow is required in streets, parks or gardens, its opulent foliage is of advantage as well. In the mountains, it is a popular domestic tree.

How will sycamore cope with the climate change? In low mountain ranges, it will probably profit from it by extending its growth period. In the city, however, it might suffer from the increasing drought stress. Certainly, this problem can be solved by providing sufficient space for the roots.

Its wood is highly appreciated, especially by instrument makers. Several basic parts of musical instruments are made from it, such as the so-called tonewood of string instruments, lutes, zithers and guitars as well as panpipes and bassoons. The highest prices are paid for so-called flame and birds-eye maple wood (i.e. trunks with wavy or birds eye-like wood fibres). In comparison to the other two indigenous maple species, the wood of the sycamore maple is the most desired, partly because of its pale colour.

Furthermore, sycamore wood is in great demand for furniture, fixtures, turnery and carving; due to its pale colour it is often used for kitchenware and table tops. It is especially suitable for the fabrication of tool handles.

Similar to North American sugar maple tree, the sap of the sycamore tree can be gathered in spring, although this spring sap is not quite as yielding as that of its relative. Up to 50 l a year can be extracted from a single tree. Its sugar content is 1-3% - meaning that it has a sweet taste without actually being syrup. Therefore, in order to obtain maple syrup, the fluid is condensed by heating. During World War I or in other, earlier times of need this procedure presented an important though laborious source of sugar.

Sycamore flowers later and less remarkably than Norway maple. Its fruits are small samaras. Their wings reduce the fall velocity – they begin to spin when falling and can thus be carried by the wind up to a distance of 125m away from the tree. The fruits have a shell which is slightly sticky. The samara can be bent open and stuck to the nose – a game quite popular with children.

In addition, the sycamore leaves have beautiful autumn coulours, in higher regions it can display a firework of yellow colours. The most impressive spectacle annually takes place in a high valley called “Großer Ahornboden”, which is named after the many maples that grow there, and is part of the Karwendel nature reserve situated near Mittenwald (Germany), at a short distance from the Austrian border.

Sycamore maple trees can live for as long as 500 years. Their trunks often reach a diameter of more than a metre. And some freestanding sycamore trees can develop into true giants. The specimen with the broadest known trunk is found near Garmisch (Germany) on the “Elmau-Alm” at an altitude of about 1000m – its trunk measures 8,70m in circumference.

The absolute highlight of this species is its bark. Old sycamore trees develop a scaly bark showing a fantastic play of shapes and colours varying from yellow to dark brown and green shades. This is why it is named pseudoplatanus – because its bark resembles that of a plane tree. The oldest scales are dark and when they finally drop off, younger, very pale layers appear.

The bark looks even more interesting, when epiphytes such as lichens and mosses colonize the old maple bark in higher regions or humid valleys. They leverage the tree in order to obtain a better position towards the light. Sensitive lichens such as the mane-like hanging beard lichen even indicate a high degree of air purity.

Translation by Wiebke Roloff