Populus nigra,mature trees grow to 30m and can live for 200 years,the bark is dark brown but often appears black, and is thick with numerous fissures and burrs, twigs are lumpy and brown in colour. leaves are shiny, green and heart-shaped, with long tips and a mild scent of balsam , young leaves are covered in fine, tiny hairs, which they shed by autumn, flowers black poplar is dioecious, meaning male and female flowers are found on separate trees , flowers are catkins (male catkins are red and female catkins are yellow-green), and are pollinated by wind , fruits once fertilised, female catkins develop into fluffy cotton-like seeds, which fall in late summer.