This wonderfully articulated centipede was living in the soil under the wood. Judging by the number of pairs of legs, I think it must be Haplophilus subterraneus, which has between 77 and 83 pairs. The books say that it sometimes glows in the dark if it's disturbed at night, so I might go back and have another look later tonight.
These are springtails - possibly Folsomia candida. There were thousands of them, probably eating fungi that were growing on the decaying wood panels.
Springtails are noted for their ability to hurl themselves into the air using a spring-loaded appendage called a furcula under their tail. If you've never seen a springtail jump, take a look at this clip from David Attenborough's Life in the Undergrowth
For some more, higher magnification images of springtails, click here
For some detailed information on the Collembola - the subclass of six-legged invertebrates to which springtails belong, click here
Take a look at Steve Hopkin's wonderful web site for ID photos of springtail species and for some truly stunning pictures of these tiny animals take a look at this Flickr gallery belonging to Eddie the Bug Man (Eddie Nurcombe)