Abstract Species of Cistus , tolerant of all climatic conditions defined as Mediterranean, and of a wide variety of soils, form an important element of the woodland and shrub associations of the Mediterranean vegetation. When these associations are destroyed, Cistus forms a stage in the successions leading back to the climax. On overgrazed land with degraded soils, certain species- C. monspeliensis, salvifolius , and ladaniferus —may form dense, extensive stands. Such stands protect the soil from erosion, add humus, and provide a cooler microclimate. The soil improves. Shade-germinating trees and shrubs start and ultimately restore the climax. A suggested explanation for the difference in inflammability reported for some stands in Europe is the presence of terpenes in the exudate of C. ladaniferus which were not found in C. monspeliensis or C. albidus .
Marcella Juhrén (Thu,) studied this question.