Oak (Quercus sp.)

Deciduous tree or occasionally evergreen, monoecious and wind-pollinated, with inconspicuous, greenish and unisexual flowers. The male flowers are pendulous and grouped in catkins, whereas the female flowers are rounded and hardly visible, developing into acorns (nut fruits).

Importance for bees: Oak is an important source of pollen in spring and sometimes of honeydew. It is mainly found in lowland areas.

Distribution: The Turkey oak (Q. cerris) grows only in southern Ticino; the downy oak (Q. pubescens) occurs in the Jura, Valais, Ticino, and the valleys of Graubünden (Rhine Valley and Val Poschiavo). The most important oak species, widely distributed both north and south of the Alps, are the pedunculate oak (Q. robur) and the sessile oak (Q. petraea), the latter being less common as it is sensitive to extreme temperatures and excessive moisture.

Flowering period: from April to June

Pollen :  ❶❷❸❹

Nectar : ∅∅∅∅

Legend: Beekeeping value is indicated using the scale: 1 (low), 2 (medium), 3 (good) and 4 (very good)
(Maurizio & Schaper, 1994; Pritsch, 2007).