The geology of the Ingleton & Stainmore coalfields

The problem is dealt with under two main headings, a) the short- term and b) the long-term effects of burning. Short-term effects. 1. On the vegetation. Calluna and the dwarf shrubs may be completely destroyed by fire, but species that are caespitose or have protected underground parts commonly survive. Regeneration of the dwarf shrubs is facilitated by their high seed-production, but they can regenerate vegetatively if not killed. The interval between successive burnings ('cycle-length'), and not fire damage, appears to be a major factor in determining the floristic composition of the vegetation. 2. On the soil. The base-status of the upper soil horizons declines through each cycle. Leaching experiments show that an increased amount of base is lost in the run-off water and leachate soon after burning. It is concluded, in view of the restriction of the rooting systems to the upper soil, that there is in this way an appreciable loss of bases from the peaty horizons at each burning. Long-term effects. 1. On the vegetation. There is evidence that 150 years ago heather moors were considerably richer in species than they are today. It is also shown that long-continued systematic burning leads to a greater loss of species than irregular and less frequent burning.2. On the soil. In all cases examined, woodland soils show a higher base-status than closely comparable soils under moorland, and it seems clear that the fertility of the moors is lower than it would have been had their former woodland persisted. The phytometrical use of green heather leaves substantiates these findings, and shows the fertility of old moors to be less than that of moors of recent origin. In the final section the economic utilisation of heather moor is discussed.