British oak (Quercus robur L.)
The defined stage of leaf appearance
The buds have flushed and the green of the new leaves are clearly visible.
After the defined stages of leaf appearance
The new leaves are unfolded and the leaf blade is fully visible.
Photos: Eija Matikainen
The flowers of male (staminate) inflorescence (hanging catkins) are open and begin to release yellow pollen. (On windy days the release of pollen is visible).
Photos: Eija Matikainen / Erwin Ulrich
Photo: Erwin Ulrich
Leaves have changed their colour from green to yellow, yellow-brown, orange-brown or brown. Often single leaves are only partly autumn coloured. The estimation of autumn colouring refers to the whole leaf area of the tree, including the leaves that have already fallen down during the colouring period, relative to the state before colouring starts.
Begining of autumn colouring
Photos: Egbert Beuker
Photo: Astrid Vasella