The areas of high gritstone plateau which form the northern spine of the Peak District form a unique landscape.
Black Hill - a typical high area
The plateau is mostly over 500m above sea-level and with an annual rainfall in excess of 1500mm (60 inches) per year. This cool, wet climate and the poor drainage of the plateau area resulted in the growth of carpets of moss (particularly a variety called Spagnum Moss) and heather. The waterlogged ground and high acidity of the soil meant that dead vegetation did not decay in the normal way and the result was a build-up of a thick layer of thousands of years worth of peat, which can be up to 3 metres (10 feet) thick.
A peat grough
The peat layer covers virtually the whole plateau, but it has been eroded by streams to form deep channels or groughs, which make crossing the plateau extremely hard work unless you keep to the watercourses or the main paths. The landscape also lacks natural features, so in misty or cloudy conditions routefinding can be extremely difficult.
The acid soils of the plateau have led to a modern vegetation consisting of heather, bilberry, mosses, and coarse grasses, which make rough going for walkers and provide good cover for birds such as the Red Grouse, Skylarks and Golden Plovers, and for mammals such as the Mountain Hare, which camouflages itself in winter by having its coat change colour to white. The winter climate of the plateau can be severe, with high winds, snow and very cold conditions.
A feature of the region is the gritstone edges which surround much of the plateau and the rocks which have been eroded into weird shapes. Some have distinctive names, such as the Woolpacks, the Mushroom, the Kissing Stones and the Salt-Cellar. Others form small tors of jumbled rocks, like the Wheel Stones. All of them form useful landmarks in bad weather.
One of the Woolpacks
The edges of the plateau are split by deep valleys or cloughs worn by the streams as they tumble down off the plateau. Grindsbrook on Kinder and Alport Clough on Bleaklow are typical. The flanks of these valleys are usually covered in bracken, which in summer can grow taller than the average man.
Blackden Clough - a typical deep valley
The landscape and ecology of this area has been much threatened by Man's activities, particularly during the last two centuries. Acid rain from the towns and factories to the west of the Peak has caused the death of most of the Spagnum Moss, with the result that little new peat is being formed. Overgrazing of the moors by sheep has caused the degeneration of the heather and bilberry covering (the sheep eat their growing shoots), leaving bare regions or areas of coarse grass. (The National Trust estimates that the number of sheep in the Kinder/Bleaklow area increased from 17,000 in 1914 to 60,000 in 1970.) Once this happens then the rain erodes the groughs and large quantities of peat can disappear. Easier access for ramblers to these areas has also resulted in erosion caused by too many people walking across a fragile landscape.