Sweet chestnut Castanea sativa

The sweet chestnut (Castanea sativa) is a deciduous tree, widespread across Europe. In autumn it produces edible nuts that have been eaten for centuries. Indeed, during the Roman Empire troops going into battle were fed on a sweet chestnut porridge.

Castanea sativa is more commonly known as the sweet chestnut and is perhaps best known for its edible nuts. The nuts are used by confectioners, eaten roasted and ground to make flour. There's even a Corsican beer made with chestnuts!

The wood of the tree is durable and is used to make furniture, barrels, fencing and roof beams. However, as it tends to split and warp it is not usually used in large pieces where structural strength is important.

Originally native to south-eastern Europe and Asia Minor, a fully-grown tree is typically an impressive 20-35 metres in height with a trunk about two metres in diameter. The bark of the tree often has a net-like pattern with deep grooves up the trunk, while its green leaves are long (16-28 centimetres), 5-9 centimetres at their widest point, and have a serrated or toothed edge.

The hardy nature of Castanea sativa means it still flourishes across large parts of central and western Europe, including Great Britain where ancient specimens can be found. Ideally it needs a mild climate as late spring and early autumn frosts can adversely affect flowering. In forests, shade doesn't unduly affect its growth and nut harvest as long as it has sufficient moisture.

Catkins hold the flowers of both sexes, with the males in the upper part and female flowers in the lower. These 10-20 cm long catkins appear in late June to July, and by autumn the female flowers develop into spiny protective cases called cupules. This prickly outer layer is designed to deter squirrels and other seed predators from getting to the brown nuts within that are shed in October.