Aspen

 As I was walking under this tree, it sounded as though raindrops were pattering on the leaves.  Looking up, I noticed that it was an Aspen and could see the leaves trembling in the wind. Unfortunately the phone has picked up the noise of the wind more than then pattering but hopefully you can see the characteristic fluttering of the leaves, even though there aren't many left!

Aspen trees are quite widespread and can be pioneer species but many people seem not to notice them.  In fact, I have walked beneath this one a number of times but never really thought about what type of tree it was. The Latin name is Populus tremula, quite literally, trembling Poplar, which is a very good description of it.  So next time you are out, keep your eyes open for a tree where the leaves are trembling.