Tree of the year 2003

Black Alder (Alnus glutinosa)

The red alder or black alder, tree of the year 2003, has become rare any time recently, because there are hardly any of its natural habitats still existing: Where are the natural courses of the streams that can wriggle unspoiltly through the landscape and whose banks may be hemmed by alder trees? And who does still have a real alder fen wood at close quarters? Eventually the ground-water table was declined in many places and there are only few stream meadows left that are flooded periodically.

As one can easily recognize, the black alder is a real water specialist: It does not mind consistently wet feet, it even tolerates ponding water (in contrast to the ash, which it is often socialized with at headwaters, but that does in the long run only bear running water).

As far as the groundwater is not too acidious and low in nutrients, the tree of the year 2003 does even thrive in transitory bogs. In contrast to the white alder (or gray alder), it is namely not bound to the presence of lime; it only does not like greater tailing.

Certainly the black alder is not absolutely bound to the lush presence of water. Since it is basically very tough, stands frost pretty good and is practically not bitten, it is often used as a so-called Vorwaldbaumart within widespread afforestations. That means that for example on frost-endangered or grassed expanses, a slight shield of alder trees is planted first, in whose protection some years later the actual target stand is yielded.

In exactly the same way the succession on virgin soils, e.g. after land slides works: First come pioneer woods like alder, birch, willow and mountain ash, in order to be replaced by more shadow compatible species, unless the ground is too wet for other tree species.

As for the rest, the alder tree has developed a unique strategy to come by the atmospheric nitrogen, which otherwise is not available for plants: It lives in symbiosis with a special bacteria capable of fixing atmospheric nitrogen. You can find those bacteria nodules anywhere at alder roots.

There is another feature that alder trees have: They are the only decidous tree species that forms real cones as fruits, just as otherwise only coniferous species do. Certainly these cones are relatively small, they only become about one centimeter long. The seeds are distributed by the wind: Where enough light reaches the ground new alder trees can grow - provided the seeds were not picked out of the old trees by birds like the eurasian siskin.


There are barely existing dangers by animals for the tree of the year 2003, merely at an early age on very sunny areas, an infestation with a particular kind of insect, the poplar-and-willow borer, may lead to problems. If the young black alders have only achieved a diameter of 3 to 5 cm, you see, the boring of aisles of the relatively grand larves of the poplar-and-willow borer may cause that the remaining wood isn't enough to stand major loads: So the young saplings may break very easily.

Beside the disappearance of the natural biosphere in recent time there is quite another matter that bothers the black alder: A root-parasiting fungus of the Phytophora type makes otherwise vital black alders die. As there are not any effective medicines yet known, the black alders can only be cut down in order to prevent an encroach of the alder-dieing on the neighboring trees as possible.

The wood of the black alder is reddish and a popular lumber. As the alder tree however does infrequently achieve major diameters, massive furniture is very rare, generally alder veneer is used. But also for curing, alders are gladly used, even sawdust of alder wood is sometimes scattered into the embers by connoisseurs.