The Alder

The woody “cones” and catkins of our native Alder (Alnus glutinosa) make for very easy identification. In this photo, taken on the banks of the River Stort in November 2020, the light green cones are actually female flowers; in spring the longer male flowers (catkins) will become bright red and will release their pollen, fertilising the ovules held inside the female flowers, and the tiny winged seeds will then be released. The brown woody cones seen on the left of the photo are the remnants of the female flowers from spring of  this year.

Alder alongside willow and aspen is a tree of wetland, happiest with its feet in water.  Geoffrey Grigson (1905-1985) wrote “Once enjoyed, an alder swamp along a Cornish stream for example, remains perennially and primevally enchanting- the trees alive and dead, moss bearded and lichen bearded..”

It is a tree whose uses to man and to wildlife are perhaps unrecognised; Alder catkins provide nectar and pollen for bees, the seeds are loved by siskin, redpoll and goldfinch, caterpillars of several moths, including  the alder kitten  and pebble hook tip moth feast on its leaves and the roots of larger trees provide a perfect  location for otters’ nests. Alder wood when kept wet is resilient to rotting, the underwater pilings  in Venice are of alder and its strong spreading roots prevent erosion of river banks.

The Royal Gunpowder Factory at Waltham Abbey (Essex) had 31 acres of alder in 1844 to provide alder charcoal, gunpowder then was 15%  charcoal and alder was the preferred wood for the charcoal. Gunpowder manufacture reached its peak during the Napoleonic Wars when the factory at Waltham Abbey produced on average 855 tons pa from 1809 to 1815; this required about 400 acres of alder wood for the charcoal.

A slightly less noisy product of alder wood was wooden clogs, worn by thousands of people working in mills, mines and on farms in the North of England until WWII.

Alder will germinate and grow on very poor soils because its roots have root nodules which contain the N-fixing bacteria  Frankia alni in a symbiotic relationship  whereby the tree gains nitrate for growth and the bacteria gain sugars produced by photosynthesis by the tree.

I recommend a wander along the River Stort from Bishops Stortford, alders galore, winter skies and with luck the plop of Mr. Ratty to ease the stresses of the world beyond the river bank.

Image: Author’s own