The effect of harvesting on stump mortality and re-sprouting in aged oak coppice forests

In Central Europe, traditional management of oak coppice forest was abandoned at the beginning of the last century, leaving large tracts of forest developing into aged coppice stands. Since the increasing importance and use of biomass as a renewable energy source, resumption of coppice management in these forests is being considered. However, there are uncertainties about the re-sprouting ability of large and old oak stumps. In this study we determined the re-sprouting ability of sessile oak (Quercus petraea (Mattuschka) Liebl.) stumps 80–100 years after the last coppice cut. Stump mortality and re-sprouting intensity were analyzed in relation to three different harvesting methods (harvester; conventional chainsaw cut; very low chainsaw cut), browsing intensity, vitality of parent trees and stump parameters. In addition, the extent to which stump mortality may be compensated by generative regeneration was quantified.On average, 16% of all sessile oak stools died within two vegetation periods after coppicing. Stump mortality was higher in unfenced areas compared to areas protected against browsing. No clear relationships were observed between stump mortality and harvesting method or parent tree characteristics.Two vegetation periods after coppicing, numerous new stump sprouts were recorded. In unfenced areas, average maximum sprout height was reduced by nearly 80%. Maximum sprout height (used as an indicator for re-sprouting intensity) was found to be unaffected by harvesting method and not related to stump height or parent tree characteristics. When stumps were cut close to the soil surface the majority of the most vigorous oak sprouts originated below ground.Our results indicate that the re-sprouting ability of 80–100 year old oak trees originating from former coppice management is still high and little influenced by harvesting methods.

► Re-sprouting ability of old oak trees originating from coppice management is high.
► Two vegetation periods after harvesting the majority of all trees were found alive.
► Sprout growth was found to be unaffected by harvesting method.
► Browsing had the strongest influence on stump mortality and sprout growth.
► Seedlings of various tree species had established among coppiced trees.