We have two heather plots here at Petts Wood which you may have noticed when walking around the wood. One plot is located in the South of the Willet Wood, adjacent to the railway tracks and the other is North of there, near to the Commons boundard path, again in the Willet Wood.
In the absence of grazing livestock on the heather it requires a lot of work, mainly from our volunteer teams, to stop the heather plots from reverting to woodland. Many birch seedlings appear in the heather as well as ingressing bracken and bramble which if left alone would return the heather plots to a very similar condition to the woodland around them. The rationale of installing the heather plots in the first place was to provide some variety in the woods and support a range of invertebrates (for more information click this link http://www.buglife.org.uk/sites/default/files/HM%20Heathland%20mosaic%20proof%20FINAL.pdf). The hope for ground nesting birds in the heather is a bit beyond the pale in these circumstances given the high number of people and dogs.
Regular walkers in the woods may have seen some areas of heather looking a bit worse for wear, especially in the Northern heather plot. Large patches appear to be dying and these patches are spreading:
These brown patches in the heather are caused by the imaginatively named “Heather Beetle”; a native species. The larvea of the beetle eat heather leaves, defoliating the plants around them before transforming into adult beetles which can fly a mile or so, find more heather to eat, reproduce and so on and so forth. If you have a close look at some of the heather plants that are defoliated you should be able to see the larvae (about 6mm in length). Unfortunately the process is just ‘one of those things’ and we have no plans to combat it rather than wait it out. The heather naturally recovers in a few years after the beetle has eaten all available food, causing the population to drop off.
The effects of the beetle are worse in heather monocultures such as ours that came about through a JCB and seed planting rather than ‘natural’ lowland heath which tends to happen on grazed poor quality soil and supports a range of heathland species. What we can do to improve the situation is to cut the affected heather in the winter to encourage regeneration and cut some other areas in the heather so there is a mix of young and old.
Whilst it’s rather ironic that heather planted to support invertabrate species is mainly supporting one that completely defoliates it we will endeavour to maintain the plots. I’ve been out in the tractor to cut the bracken around the raised pathways to stop it ingressing into the heather and we will monitor the situation throughout the summer.