Identifying Oak

Oaks are long lived trees, many being 500 or more years old. Oak wood is good to work with, as it cleaves well but younger wood can stain the hands (due to tannins). There are two flavours, Sessile Oak (Quercus petraea) and Pedunculate Oak (Quercus robur), which readily hybridise.

Leaf

Simple leaves arranged alternately around the stem. The two (main) species of oak differ in the length of the leaf stalk / petiole. In the pedunculate oak, the leaf stalks (petioles) are quite short (less than 0.5cm) whereas in the sessile oak the leaf stalks are more obvious (1 to 1.5 cm in length). The edge of the leaf is lobed and wavy. There are 5 to 7 lobes on each side of the leaf. In the pedunculate oak, the lobes tend to taper into the stem so that the leaf stalk / petiole is scarcely noticeable. Leaves of the sessile oak may have fine hairs on the underside – particularly on the main vein or midrib of the leaf

Buds, Bark and Stem

Buds tend to be clustered near the end of the winter twig; they have rusty brown over-lapping scale leaves. The bark is grey and in older trees fissured. It often supports lichens.

Flowers and Fruits

The Oak produces male and female flowers. The male flowers are drooping catkins, and their pollen is dispersed by the wind. The female flowers are very small and found in the axils of the leaves. When fertilised, these will develop into acorns. The acorns are up to 2–2.5 cm in length, and (in the pedunculate oak) are attached to a peduncle or (3-7cm) acorn-stalk. One to four acorns are attached to each peduncle. In the sessile oak, the acorns appear to sit on the twigs.

Winter Twigs

Identifying Oak

Leaf

Buds, Bark and Stem

Flowers and Fruits

Winter Twigs

Tree species