This dataset includes laboratory spectral measurements on 54 leaves collected from European fly honeysuckle (Lonicera xylosteum L.), alder buckthorn (Frangula alnus Mill.) and common hazel (Corylus avellana L.) in the Viikki arboretum (60◦ 13’N, 25◦ 00’E), in Finland. The measurements were conducted in the darkroom of the remote sensing team at Aalto University (Espoo, Finland) from 5 to 10 July 2023, during the peak growing season. Directional-hemispherical reflectance and transmittance factors were measured at wavelengths from 350 to 2500 nm for adaxial (upper) and abaxial (lower) leaf sides. In addition, we recorded spatial coordinates of each bush and took photographs of the bush, its environment and the sampled branches. The table "spectral_T_adaxial.csv" contains the directional-hemispherical transmittance factors of the adaxial leaf sides. The table "spectral_T_abaxial.csv" contains the directional-hemispherical transmittance factors of the abaxial leaf sides. The table "spectral_R_adaxial.csv" contains the directional-hemispherical reflectance factors of the adaxial leaf sides. The table "spectral_R_abaxial.csv" contains the directional-hemispherical reflectance factors of the abaxial leaf sides. The table "description.csv" contains metadata for each sampled leaf. The file "sample_photos.pdf" contains photographs of the leaves, branches, bushes sampled and their surrounding environment. For further details on data collection, the measurement process and the content of the data files, see README.pdf. If using the data, please cite the Mendeley Dataset: Mercier, Audrey; Karlqvist, Susanna; Hovi, Aarne; Rautiainen, Miina (2023), “Leaf spectra of alder buckthorn, common hazel and European fly honeysuckle”, Mendeley Data, V1, doi: 10.17632/3bkrwhk4p3.1 Funding: European Union – NextGenerationEU as part of the Research Council of Finland project ARTISDIG (decision number 348152). We thank Daniel Richterich, Ellinoora Leivo and Tuomas Peurala for their support in locating the bush species in the Viikki arboretum.

2023