Effects of relative irradiance on the leaf structure of Fagus sylvatica L. seedlings planted in the understory of a Pinus sylvestris L. stand after thinning Ismael Aranda, Luis Felipe Bergasa, Luis Gil and José Alberto PardosAnn. For. Sci., 58 6 (2001) 673-680DOI: https://doi.org/10.1051/forest:2001154