Specific leaf area (SLA) was determined for five vascular plant species of contrasting functional groups (evergreen tree, deciduous tree, herb, grass). Samples were collected in August 2018 in the Northern Black Forest, SW-Germany. Upon sampling, vascular plant leaves were put into plastic bags to avoid shrinkage. Leaves were kept cool and measured within 24 hours after return to the laboratory. Leaf petioles were cut off and excluded from surface area measurements (see protocol in Pérez-Harguindeguy et al. 2013). Leaf area was measured using a flatbed scanner. After area measurements were conducted, all individual samples were oven-dried at 70 °C for 48 hours and weighed. Species nomenclature followed Oberdorfer (2001).