Botanical lore
Like willow,
alder is found near water, whether rivers, lakes or wetlands. Individually,
alders can look gnarled and short, but growing collectively their light green
foliage will shoot up high, allowing a rich canopy of plants to grow around its roots,
such as meadowsweet, ground elder and wild garlic. Because these in turn attract
a wide variety of animals, that include insects, amphibians, water birds and small mammals (as well as
fish when part of a shaded river bank), alder creates a fertile, vibrant, lush
green space around it.
It
can also grow in mixed woodlands, alongside ash, birch and willow. Alder roots
grow deeply into wet ground, binding and invigorating soggy ground in places
that other trees cannot survive because of deficiency in oxygen. Their roots not
only protect river banks from erosion, alder contain a high nitrogen content and
their roots can bind nitrogen from the air through simple symbiosis, a fact
revealed in the autumn when their grey-blackish leaves cover the ground.
However this nitrogen is nutritious and, with other minerals, is passed on into
the undergrowth. Because alder strengthens, drains and ventilates soil, it
protects wetlands from becoming marshland. Smooth and olive brown in colour
initially, with light horizontal sap pustules, alder bark becomes fissured and
dark as it matures. The wood is reddish and the freshly cut sap is orange-red,
appearing like blood. Most durable when constantly wet, alder wood has been in
use for centuries in creating bridges, pumps, sluices and piles (for causeways
across marshes such as Ravenna, and for medieval cathedrals and buildings, that
include parts of Venice). Older still are the crannogs - built in Neolithic
times.
After about
thirty years alder matures and produces sexes of flower on one tree
(monoecious). Its leaves appear after the flowers, and are sticky to begin with
(hence its latin name glutinosa). The male catkins hang down like the birch
(alder belongs to the birch family), while the female catkins mature into dark
woody cones, sometimes called wattles, which is unusual for a deciduous tree in
the temperate zone. The cones often stay on the tree during the winter while the
winged nutlets, using tiny air bags, fly or float away on the water to germinate
downstream.
Alder
has been in use for centuries. Its bark was used to tan leather and for dyes, as
were the leaves, while its wood, like oak was used for charcoal production (used
in smelting iron), and the sticky twigs in spring were made into brooms or
besoms to catch remaining fleas in its leaves. Alder is rarely used for
building, as woodworm is attracted to its protein-rich wood. Both leaves and
bark are astringent and antiseptic and can be used as a gargle, and a
preparation from the bark was used to heal rashes or festering wounds. In
homoeopathy the bark tincture is still used for skin and glands.
Odd notes: Due to alder is the saying: 'what can no house ever contain?' (the piles on which it is
built).
Bog alder or ‘scottish mahogany‘ excellent for chairs due to
long
immersion in bog.
Wood: pipes, milk-pails, water-resistant uses,
cigar-boxes (reddish & cedar-like) oars, cricket bats, horsewhips, bridges,
troughs;
Bark: (stains reddish when cut) red dye for
tanning and fish-nets ;
Flowers: green dye ;
Twigs: charcoal and gunpowder, brown dye ;
Leaves: tans leather, makes horses tongues
black, catches fleas (sticky), pigs will not eat ;
Medicinal: bark decoction for inflammation
and swellings. Alder leaves in shoes ease sore feet;
birch family: betulaceae common alder (alnus glutinosa)