Hello Dave,
On a properly managed Grouse Moor you will seldom find Heather that comes up much higher than mid calf heightso perhaps about 12" tall. When it gets to this height it is usually marked down as ready for the next burning. Burning removes all the vegetation above ground level and permits fresh regeneration from the rootstocks well underground. Every Moor is partially burned each season thus ensuring that there is always a fresh supply of young leaves for the Grouse to feed on. Generally but but not always a broad swathe of vegetation surrounding the area to be burned is cut and cleared of vegetation the idea being to make a fire break, then the heather inside the box is burned.
This has to be carefully controlled as if it got out of hand it can devastate a moor which will take a decade or more to recover. Most Grouse Moors are a very long way from water supplies and the fire services have very great difficulty in accessing these moorlands with vehicles carrying water. Having been involved in putting a couple of these blazes out in the past I can tell you it is hard and dangerous work.
Left alone Heather can grow up to four or five feet in height, but by then it is very 'leggy' and damned difficult to get through. You usually only see this in clearings when the surrounding land has been afforested, a sad fate in the past for many a grouse moor. Each year part of my consultancy work is carried out on Grouse Moors in the Counties of Durham and Northumberland. Tomorrow if the weather is fine I'll get some pictures of the patch burning from one of them that I am due to visit. Burning is usually carried out from late October through to March, depending on the weather and access to the moors, often difficult in winter weather.
Harry
