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.

 

Information on the most important forest tree species in Switzerland

European beech – Fagus sylvatica

The European beech is the second most common tree species in Switzerland. It occurs in almost all parts of the country, but is absent in the Alpine valleys with low precipitation.

Ash – Fraxinus excelsior

The ash is widespread and forms extensive forests in the northern Alpine foothills together with the sycamore maple.

Pedunculate oak – Quercus robur

The pedunculate oak needs a lot of light and a long, warm growing season. That is why it is most common on the Central Plateau and in the eastern Jura.

Sessile oak – Quercus petraea

The drought-resistant sessile oak is more common in Switzerland than the pedunculant oak, but is more susceptible to late frosts.

Norway spruce – Picea abies

The Norway spruce is the most common and widespread tree species in Switzerland. Its main natural distribution area is the Alps, the Pre-Alps and the western Jura.

Silver fir – Abies alba

The third most common tree species in Switzerland, the silver fir, occurs mainly in the western Jura, the central Swiss Plateau and the Pre-Alps.

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