Sphagnum regrowth after cutting

Sphagnum biomass is commercially harvested from semi-natural and natural peatlands. In this article we analyse the effects of harvesting Sphagnum by cutting off the top parts of the plants and leaving the cut stems to regenerate. We tested regrowth of Sphagnum palustre and Sphagnum papillosum in natural peatlands with high Sphagnum productivity in Kolkheti (Georgia, Transcaucasus) using two cutting depths (5, 10 cm) and two cutting intervals (1, 2 years). In Germany we measured regrowth of S. papillosum in an experimental Sphagnum farming field 2.5 years after cutting off the top 5 cm. Regrowth of Sphagnum was similar in both regions, with new capitula attaining 80 % cover one year after cutting and similar biomass productivities (Kolkheti: S. palustre 169–329 g m-2 yr-1, S. papillosum 152–246 g m-2 yr-1; Germany: S. papillosum 249 g m 2 yr-1). In Kolkheti, regrowth was independent of cutting depth. No relationship between site conditions and biomass regrowth was identified in either Kolkheti or Germany, probably because of the overarching effect of favourable hydrological conditions. This study shows that cutting is an appropriate method for harvesting Sphagnum and allows repeated harvests with fast Sphagnum regrowth. For S. palustre, it may even be possible to harvest annually without reducing yields.