I have a tree growing for the last few years in my garden, but I'm not sure what it is? I've let it grow so far, but would love to be able to identify it. I've posted a pic of it below along with some leaves.
Salix caprea .... aka Goat willow.
There are male and female ... the female have insignificant green catkins and lots of fluffy seeds that drift on the wind. The male have 'Pussy Willow' type catkins.