How to recognise seed mast?

Seed masting is the mass production of fruits and seeds by all or most individuals in a stand of trees. The term 'fattening' comes from the formerly common practice of fattening pigs under oak trees. In forestry, different degrees of seed mast are distinguished:

Classification of seed quantities in forest trees, according to Rohmeder (1972)
Description Code Stand level Fruits/seed on indivudal trees
No mast 0 0 < 10% of all trees in the stand None or few
Partial mast 1 10‒50% of all trees in the stand Little to abundant
Half mast 2 50‒80% of all trees in the stand Abundant to lush
Full mast 3 > 80% of all trees in the stand Lush to expansive

Foresters and hunters refer to the years of massive fruit and seed production by all or most of the individuals in a forest stand as full mast. 

A particular form of grazing is the acorn crop, which refers both to an exceptional acorn year and to the practice of letting pigs feed on oak and beech acorns in the forest.


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