This dataset includes litterfall data from the experimental plots at the Climoor field site in the Clocaenog forest, NE Wales. Litterfall (natural senesced plant material) was collected in litterfall traps (12 x 7.5cm pots standing slightly proud of the soil/litter surface, emptied monthly). Litterfall was calculated by drying the contents of the traps and weighing the samples; values were calculated for each quadrat (total weight (g) only) and for each plot (total weight (g) and weight per metre squared (g/m2)). Data spans the periods Oct 1999 to Jan 2004 and July 2008 to June 2011. Data was collected by CEH staff and PhD students trained in the use of the methods. Climoor is a climate change manipulation experiment that utilises automated roof technology to produce drought and warming experimental treatments that reflect climate change predictions for the next 20-30 years.