Bark

Learn the textures

• Smooth: thin and unbroken, as on beech and on young trees of many kinds.
• Ridged or furrowed: deep grooves with ridges between them. White ash has ridges that cross in a diamond pattern.
• Scaly or plated: broken into flat pieces. Many pines have plates, and some spruces have small scales.
• Peeling or papery: thin layers that curl away, as on paper birch.
• Shaggy: long strips loose at one or both ends, as on shagbark hickory.
• Mottled and flaking: patches that peel to reveal a paler layer underneath, as on sycamore and plane trees.

Lenticels

Lenticels are small pores in the bark that let the tree exchange gases. On birches and cherries they show as horizontal dashes, a useful clue on young bark.

How bark changes

Young trees of most species have smooth bark. Furrows and plates develop as the trunk thickens and the outer layers crack. The bark of a tree at the edge of a wood, in full sun, can look different from one in shade. A sapling's bark tells you little, so check leaves and buds too.

How to look

Look at the trunk at chest height, then at a branch about as thick as your arm. Note the texture, the colour, whether the ridges run straight or cross, and how thick the plates are. A photograph in flat light helps you compare it with a guide afterwards.

Go deeper

Three pages go into bark in more detail: texture, colour and how bark changes as a tree ages. The key also has a bark route, which lists the trees that match the texture you pick.