I have heard the "Tree O'Clock" world record attempt mentioned on Autumnwatch a few times, and at a local wildlife meeting I went to recently. The aim is to "plant your very own tree as part of a Guinness World Record attempt" It's happening all over the UK on the 5th of December from 11am-12noon. 1 million trees need to be planted in order to beat the record. To find out where you could do this check out the website: http://www.bbc.co.uk/breathingplaces/treeoclock/
If you plant a tree please let me know, it would be great to hear your experience from it. I will be taking part and planting a tree with WildDerby at Allestree Park.