Birch

Birch - Betula spp.

Three species of Birch grow wild in the British Isles.

• The dwarf Birch Betula nana, seldom bigger than a shrub, is found locally in the Scottish Highlands - it is one of the world's hardier plants, able to flourish even on the tundra.
• The two that grow to tree size in Britain are the Silver or Warty Birch, Betula pendula - and the Downy Birch, Betula pubescens.

Telling them apart

Silver Birch twigs are hairless but bear tiny warts and vice versa for Downy

The leaf edges in the Downy Birch only have a single series of teeth - they are double-toothed in Silver Birch.

Both have white bark as the tree gets older - but it is particularly bright in the Silver Birch

Normally the Downy Birch is a smaller tree, with more upright branches and becomes commoner as you go North and West in Britain where it often grows on damp, peaty moorlands.

Silver Birch branches droop at the tips - which is why its scientific name is pendula or hanging. To complicate matters, some individual trees show characters intermediate between these two species; these are normally hybrids.

Birch biology

Birch catkins open about April along with the leaves.

Birch is wind pollinated - the male catkins or lamb's-tails shed the pollen and later break up.

The pollen blows onto the female catkins which are smaller and stand erect looking like bristly green caterpillars - during the Summer the fertilised female catkins ripen, grow longer and eventually hang down to release the winged seedlings which are carried away on the mid-Autumn wind.

Seeds that alight on suitable substrates germinate and sprout the next Spring; Birches are typical "pioneer" trees, able to invade and colonise bare land successfully.

Sixty years is a good age for a mature Birch.

Uses of Birch

The timber of both these Birches is similar but of little commercial value in Britain at present although in Scandinavia, where the trees are larger and straighter, the wood is used for furniture and when peeling the veneers, for use in Birch plywood.

In Britain, the smaller trees are used for turnery to produce broomheads, tool handles and many kinds of small wooden objects.

Birch logs burn well, the twigs are still used for sweeping brooms or besoms, and for steeplechase jumps.

Silver Birch are popular garden trees and other Betula species, particularly those with whiter trunks are widely available.

A powerful diuretic, yet kind on the kidneys, can be concocted from Birch leaves and wine fermented from the rising sap in Spring.