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In Europe, the alder is one of the most common deciduous trees. It is known, among other things, for its deeply fissured bark and the easily usable wood. But there are also some interesting things to report about the fruits. Did you know that the alder is the only deciduous tree that forms cones? In this article you will learn many more facts worth knowing about the fruits of the birch tree.

The small nuts of the alder are often used for decorative purposes

Optical features

Since the alder is a birch family, the deciduous tree has the catkins typical of this tree species. They are the preliminary stage of the later trained wingnuts. Due to its striking appearance, you can easily recognize the alder by its infructescence.

  • as flower long catkins
  • small nuts
  • either winged
  • or wingless
  • are formed in cones

Properties of different types of alder

Although the cones are a characteristic feature of the alder, they differ slightly from variety to variety. Here is an overview of the fruits of different types:

  • Heart-leaved Alder: woody, dark brown, up to 3 cm long
  • Black alder: initially green, later dark brown, woody
  • Green alder: initially green, later dark brown, woody
  • Purple alder, initially green, later dark brown, woody
  • Alnus company alder: also green at first, but later much darker (almost black), woody, fruits remain on the branches even in winter
  • Red alder: woody, initially green, later dark brown to black


First, the alder forms elongated flowers, which are called catkins because of their shape and bushy appearance. These resemble the blossoms of the hazel. They have either male or female flowers. An alder is usually bisexual, although a catkin is only one sex or the other. In botany this property is called monoecious. The birch family has a unique feature in terms of further development: the female inflorescences lignify into cones over time. This process is unique among deciduous trees. And something else is quite rare: alder cones remain on the tree even in winter. Even if the alder has long since shed its foliage, it is easy to recognize it by its cones. Finally, small wingnuts are formed, which contain the seeds of the alder. The multiplication happens mainly over the wind.

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