Effects of removing the litter and humic layers on heathland establishment following plantation removal Original Research Article

We investigated ways of optimising the establishment of Calluna vulgaris-dominated heathland vegetation following removal of pines from afforested heathland using a randomised block experiment. Removal of the litter layer, or both the litter and humic layers, resulted in a higher initial establishment rate of C. vulgaris compared to in the control plots. The effect of adding heathland clippings suggested that the rate of establishment of C. vulgaris was limited by seed availability in plots from which both the litter and humic layers had been removed, but not in those from which just the litter layer had been removed. Removal of both the litter and humic layers did, though, result in a long-term reduction in the depth of the humic layer, a lower loss-on-ignition and lower level of nitrate and total nitrogen compared to in the control plots. The optimal method for establishing heathland vegetation at a site will depend on: (1) whether there is a viable seedbank of C. vulgaris and other desirable heathland species present; (2) the importance of quickly establishing a high cover of desirable heathland species; (3) the likely long-term effects of soil nitrogen levels on the maintenance of C. vulgaris dominance; (4) the practicality of removing and disposing of the litter and humus layers.