Ring-barked birch

On Greenham and Crookham Commons we have silver birch (Betula pendula) and downy birch (Betula pubescens).

These are native throughout northwest Europe including the UK, and have very high wildlife value. The light canopy of small leaves casts dappled shade, allowing a varied ground flora of mosses, grasses and flowering plants which provide varied food for invertebrates, birds and mammals. In Britain silver birch supports 230 insect species (162 of which are strongly dependent on birch) and is specifically associated with several fungi. The insects, and the copious seeds, attract numerous birds.

But birch is natural pioneer, colonising bare ground with its small wind-blown seeds and thriving on nutrient-poor acid soils with the assistance of mycorrhizal fungi. Once established, a birch wood produces up to 4 tonnes of leaf litter per hectare annually, enriching the soil and facilitating further succession to oak and other longer-lived trees.

Birch is one of the major types of woodland around the edges of the commons, and there is no intention to remove it all! However, locally and nationally there is a lot of birch woodland, while lowland heath is much scarcer and shrinking in area. Some areas of birch, especially where they have recently invaded heathland areas and some heather is still present, are cleared by felling and stump treatment (with glyphosate or triclopyr) to prevent re-growth. Some large specimens are ring-barked to leave standing dead wood, a valuable invertebrate habitat.

Some birch is also cut commercially on the commons (not by the GCCV) for besoms and horse-racing hurdles. Some of our scrub control is actually aimed at maintaining traditional coppice areas, rather than to eradicate birch entirely.

Some locally important species, such as the nightjar, like a gradual transition between woodland and heath. Birch is therefore selectively felled to create scalloped edges to the woods, with scattered trees left as standards in cleared areas.