The Silver birch (Betula pendula) is from the Betulaceae family, just like Hazel (Corylus) and Alder (Alnus), which also have flowers in the form of catkins (see my previous two posts A Snowy Adventure and The Birds and the Trees).
At the moment only the immature male catkins are visible (as they have been since autumn) dangling at the end of tree shoots.
Female Catkins develop after the leaves unfurl in spring. They face upwards, are bright green and smaller than the male ones; flowering between April and May. Unlike the fertilized Alder catkins these do not become woody and remain on the tree for seeds to disperse from there. Instead seed dispersal occurs as the female catkins disintegrate and are carried away by the wind as they fall from the tree.
The paper like white bark of the Birch sheds to uncover newer, cleaner bark underneath; plus dark diamond shaped fissures develop as the tree ages.
Two birch trees are native to the UK, the other is the Downy birch (Betula pubescens). It is possible for these to hybridize with one another however individually they can be differentiated. The Downy birch has hairy, single-toothed leaves and hairy shoots (which is how it gets its name); plus the leaf base is rounder. The leaves of the Silver birch are more angular, double toothed around the edges and hairless (the shoots are also hairless). The Downy birch also prefers damper soil than the Silver birch but both are naturally found in woodlands.
The Silver and Downy Birches have open canopies allowing flowers such as violets (Viola), Primrose (Primula vulgaris), Bluebells (Hyacinthoides non-scripta) and Wood anemone (Anemone nemorosa) to florish beneath them. Several fungi are linked with Birch trees too, such as Fly agaric (Amanita muscaria), Woolly milk cap (Lactarius torminosus), Birch milk cap (Lactarius tabidus), Birch brittlegill (Russula betularum), Birch knight (Tricholoma fulvum) and the Birch polypore (Fomitopsis betulina).
These trees can support over 300 insect species. They are a good food source for the caterpillars of Angle-shades (Phlogophora meticulosa), Buff tip (Phalera bucephala), Pebble hook-tip (Drepana falcataria), and Kentish glory (Endromis versicolora) moths. Several Bird species make use of these trees including woodpeckers (Picidae), which nest in the trunks, along with Siskins (Spinus spinus), Greenfinch (Chloris chloris) and Redpolls (Acanthis) that feed on the seeds.
Uses for Birch trees include the manufacture of furniture, handles and toys as well as the process of tanning leather.
In times gone by it was used to make bobbins, spools and reels for the Lancashire cotton industry as well. To the Celts Birches symbolised purity, renewal and love. Later on brooms were made using birch twigs in order to clean rooms. In Finland they are the national tree.
There are several threats to Birch trees, two fungal pathogens (Marssonina betulae and Anisogramma virgultorum) which can cause Birch dieback and eventual death. Bronze birch borer (Agrilus anxius) can also attack native trees.
More information on both can be found on the Forest research website, see the links Birch dieback and Bronze birch borer.
Bee in the Moment 