Pterocarya fraxinifolia is a fast growing deciduous tree commonly called Caucasian Wingnut or, sometimes, Caucasian Walnut, which favours deep damp soils such as on river banks (It is a relative of the walnut). It is native to southeastern Europe but was introduced to the UK over 200 years ago. It has a short thick trunk and can grow to around 30 meters in height. It has very long (60cm) leaves and large green male catkins (10cm) in Spring.
Funky Facts File: Its wood is of little commercial value although it has been used for making matches. Despite liking deep damp soils, it is drought tolerant and much prefers sunny positions.