Long-Term Survival of Saplings during the Transformation to Continuous Cover

Abstract: The Glentress Trial Area is an extensive research area in southern Scotland of 117 ha where a long-term trial of the transformation of even-aged plantations to continuous cover has been in progress since 1952. During the assessment of permanent sample plots in 1990 information on the species and spatial position of saplings (trees taller than 1.3 m with a diameter at breast height of < 7 cm) was recorded. This provided a unique opportunity to investigate the long-term survival of saplings during the transformation process when the Trial Area was reassessed in 2009. The main finding was that 37% of saplings survived the 19-year period and the majority developed into trees (≥7 cm diameter at breast height). There was considerable variation between species, the lowest survival of saplings was European larch (Larix decidua Mill.) (13%) and the highest European beech (Fagus sylvatica L.) (55%); however differences between species were not significant. There were, however, significant differences between the six management areas with three with high sapling survival (55% to 61%) but others much lower (27% to 32%). If this result is confirmed by other studies, covering a broader range of sites, management guidance that assumes 90% survival will need to be revised.