A pair of knobbly trees

After being slack yesterday I thought I'd better make a proper effort today.  But where does all the time go? It was nearly 5 by the time I got to the carpark at Elsdon so I only spent about an hour - and I got rained on, that wasn't supposed to happen!  It was getting a bit dark for good pictures but this one seems to have come out okay.  I don't know what this variety of tree is called but now that I've noticed them it seems there are quite a few of these knobbly ones around.