Leaf samples of Acer pseudoplatanus, Dactylis glomerata and Potentilla reptans were collected in seven LandKlif quadrants along a climate gradient in summer 2020. In each quadrant, leaves were sampled in two habitats (forest and open landscape). In each habitat, three leaves from seven individuals of each species were collected. Specific leaf area (SLA) and leaf dry matter content (LDMC) of each leaf sample were determined in the lab. In addition, nitrogen content was measured at the level of individuals. This dataset contains the mean SLA and LDMC of the leaves sampled from each individual, as well as information on the site where they were collected. LandKlif is funded by the Bavarian State Ministry of Science and the Arts within the Bavarian Climate Research Network (bayklif). Within the five year funding period of bayklif, five interdisciplinary senior research associations and five junior research groups are be financed with a total sum of 18 million Euro. LandKliF, as one of the five interdisciplinary senior research associations, addresses the effects of climate change on biodiversity and ecosystem services in semi-natural, agricultural and urban landscapes.