Light limitation of growth in 10-year-old seedlings of Taxus baccata L. [European yew]

Taxus baccata L. is a rare and endangered species with restricted occurrence. One or two-year-old yew seedlings occur quite frequently in natural stands of the species, but older seedlings are rarely observed. Therefore we investigated the relationship between light intensity and the growth rate of ten-year-old seedlings of the European yew Taxus baccata (L.). The study was conducted in a preservation area established in 1999 in order to protect the gene pool of the ‘Cisy Staropolskie’ Reserve in the Bory Tucholskie Forest (northern Poland). A total of 570 three-year-old seedlings were planted under the canopy of a 45-year-old forest stand composed of oak (50%), birch (40%) and hornbeam (10%). Measurements of seedling heights were taken in 1999, 2003 and 2005. In 2005, the current annual growth increment was measured. Relative Photosynthetic Photon Flux Density (RPPFD) up to 30% had a positive influence on the height and annual height increment of the yews, but most of individuals grew below 5% RPPFD. This suggests that increasing light level would increase growth of yew in both natural recruitment and planting.