The Alder tree (1) is a cousin of the Birch and the Hazel, and like them its flowers and seeds are borne in catkins. It is usually to be found growing by the side of a slow-running stream, over which its slender branches bend gracefully, while its spreading roots cling to the boggy soil at the water’s edge. For the Alder does not thrive in dry ground: it is a water-loving tree, and its many tiny roots attract moisture, and suck it up greedily; so that the ground where the Alder grows is often a marshy swamp.
Sometimes you will find an Alder which has grown into a lofty tree with a rough brown-black bark, and with many large branches; but it is much more frequently found as a low-growing and rather gloomy bush, about the same size as the Hazel.
The wood of the Alder is much sought after for buildings which stand in water. In Venice one of the most famous bridges, the Rialto, is built on piles, or great posts of Alder driven deep into the bed of the canal: and one reads in old history books that boats were first made of the trunks of the Alder tree. But it is of no use for fences or gate posts, as it decays quickly in dry soil.
THE ALDER
1. Alder Tree2. Leaf Spray3. Stamen Catkins
4. Seed Catkins5. Last Year’s Seed Catkins6. Next Year’s Seed Catkins
If you watch a woodman cutting down an Alder tree you will notice that the chips which fall under his axe are very white; but soon they change colour and become a reddish pink. The hard wood knots which are found in the tree trunk are beautifully streaked and veined and are much prized by furniture makers.
In early spring you should walk to the banks of a stream and look for an Alder tree. Like the Hazel, you will easily know it by its winter catkins, though these are very different from Hazel catkins. Clinging to the boughs you see groups of small brown oval cones, which are quite hard and woody and which snap off easily. These woody cones are the withered seed catkins (5) of last year. As well as these you find bunches of long drooping caterpillars with tightly-shut purple-green scales, which will not unclose till the spring days come. These are the young stamen catkins, and they have taken six months to grow so far. By these you will always know the Alder tree; and it is most interesting to watch day by day how its catkins grow and change.