This dataset includes all measurements of roots from the Climoor fieldsite in the Clocaenog Forest. The data spans three periods: 2003-2004, 2008 and 2011. In 2003 and 2004, 5cm x 15cm plastic root cores were measured, and roots manually picked out the soil. In 2008, root biomass was determined by sieving and washing. In 2011, root biomass, density and length was also determined using sieving and washing. However, the methods used in each of the periods differs so significantly the data should not be directly compared, only differences between experimental plots should be considered.