Any area of open ground will, if left to nature, gradually turn into woodland. This is a natural regeneration process, it is happening around us all the time and largely goes unnoticed. First bare ground loving plants like poppies and daisies will appear and then the grasses take over. Amongst the grasses shrubs start to take hold and then, over a much longer period of time, the trees grow and develop and the woodland is formed. It can take a hundred years or more but it will happen!
At the point when the shrubs are at their peak the resulting habitat is generally called scrub. In some places where there is regular livestock grazing the animals will browse and keep the scrub at bay. In other areas, often where grazing is not practical, the scrub takes a firm hold. If the soil or terrain is such that the development of trees is impaired then scrub habitat becomes almost the norm.
Scrub is an important habitat in its own right and is essential for some birds' survival. The nightingale, for example, thrives in scrub but nowhere else. Scrub is formed mainly of shrubs from the rose family; bramble and dog-rose, hawthorn and blackthorn being the most common. On acid soils gorse becomes the dominant species and bracken often occurs too.
There are areas of scrub almost everywhere you go in Dorset and it comes in two forms.
- Mixed scrub is a naturally generated collection of bushes that are not managed but are developing on their own in conditions that suit them.
- The other is what we know as hedgerow scrub; hedges are a shrubs (and trees) that are managed and form boundaries between fields.
It is easy to overlook the importance of scrub. We tend to think mixed scrub is untidy and indicates neglect whereas hedges need to be annually manicured to keep them tidy as well as functional. Nature reserves often have mixed scrub which is controlled to ensure the benefits of scrub are retained without losing the underlying grassland or heathland habitat that it is invading. Thank heavens for the conservation volunteers!