Mast (botany) some domestic animals consume. Mast is found in two forms. Mast is generated in large quantities during mast seeding events (or masting, mast events). Mast seeding is a population-level phenomenon that is hypothesized to be driven by economies of scale, weather, and resources. These pulses of resources drive ecosystem-level functions and dynamics. Tree species such as oak, hickory, and beech produce a hard mast—acorns, hickory nuts, and beechnuts. It has been traditional to turn pigs loose into forests to fatten on this form of mast. Other tree and shrub species produce a soft mast, such as raspberries, blueberries, and greenbriar.
Forests of the Iberian Peninsula blackberry bushes, blackthorn, hawthorn and other more or less thorny shrubs; this role can also be filled by smaller thorny plants, "los piornales", and clumps of broom. The major forests in this area are beech, oak, birch, and fir. Beech forests ("Fagus sylvatica") are found in the mountain layer of the Iberian Eurosiberian region from 800 to 1500 metres up. The soil is cool, as often chalky as siliceous (rich in silica), and nearly always acidified by rain. The layer is characterised by the beech tree. The beech tree projects a deep shadow, and so its dense foliage usually excludes