The Norway spruce was introduced into the UK from Scandinavia in the 16th century. It is familiar to us all as the 'original' Christmas tree and displays hanging, reddish-brown, oblong…

The muntjac deer was introduced into the UK from China in the 20th century. It has gained a stronghold in southeast England, where it can cause damage to our woods through browsing.

Due to the devastating effects of Dutch elm disease in the 20th century, the English elm is rarely found as large tree, but is more common as a shrub along hedgerows, or sometimes in woodlands.…

Due to the devastating effects of Dutch elm disease in the 20th century, wych elm is rarely found as a large tree, but is more common as a shrub along hedgerows and streams, and in upland areas.…

The Sitka spruce was introduced into the UK from North America in the 19th century. It has been widely planted as a forestry tree; look for classic needle-like leaves and pale brown, domed cones…

Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from…

These non-native limpets arrived from America in the 19th century and are now widespread in the UK. They form stacks and have a specially adapted shell which, when flipped upside down, looks like…