roots and trees...

So I've been foraging!  Walking round local woods and forests, any areas with trees really, and looking for trees that have been felled already, fallen over themselves, or where the roots are slightly exposed already from erosion or poor soil.  So far I've founda few:  I'v had an offer from a friend with a farm, saying they have a lot of trees that have exposed roots by a river that I can go and have a look at, My dads got a sucker plum tree which he says Im more than welcome to (but I'm worried if it's a sucker, it will be growing from the old stock and be a funny shape).  I've found a few old ones down on an old train track in Cornwall, that have fallen and shouldn't have too much root damage, if they're not too rotten anyway.  Here are a few snaps I've got so far: