This dataset contains reflectance and transmittance spectra of leaf and needle samples, collected near peak growing season in 2019 and 2020, from three study sites in northern and central Europe: Hyytiälä (61°51'N, 24°18'E, Finland), Järvselja (58°17'N, 27°19'E, Estonia), and Bílý Kříž (49°30'N, 18°32'E, the Czech Republic).
The spectra have been reported in Hovi, A., Lukeš, P., Homolová, L., Juola, J., Rautiainen, M. (2022a). Small geographical variability observed in Norway spruce needle spectra across Europe. Silva Fennica vol. 56 no. 2 article id 10683. https://doi.org/10.14214/sf.10683. If using the data, please cite the above publication and the Mendeley Dataset: Hovi, A., Juola, J., Lukeš, P., Homolová, L., Rautiainen, M. (2022b). Tree leaf and needle spectra for three sites in northern and central Europe. Mendeley Data, V1, https://doi.org/10.17632/t5f554s7cn.1.
For the following species and study sites, we collected samples from three individual trees per study site. For each tree, we measured three samples of top-of-canopy (predominantly sun-exposed) and three samples of bottom-of-canopy (predominantly shaded) foliage. For evergreen conifers, we sampled current-year and one-year-old needles, which doubled the number of samples. For each tree, characteristics (height, diameter) of the tree and the surrounding forest stand were recorded.
Norway spruce (Picea abies (L.) H. Karst), all sites
Scots pine (Pinus sylvestris L.), Hyytiälä/Järvselja
silver birch (Betula pendula Roth), Hyytiälä/Järvselja
black alder (Alnus glutinosa (L.) Gaertn.), Järvselja
European aspen (Populus tremula L.), Järvselja
The spectra of the following five rare species in the Järvselja site were also measured. These data were not reported in Hovi et al. (2022a) but are included here for the sake of thoroughness. For these species, we sampled one tree per species and only top-of-canopy foliage. Three samples per each tree were collected. These trees were all young (up to 5 m in height). No measurements of the tree or stand characteristics were made.
American hazelnut (Corylus avellana L.)
small-leaved linden (Tilia cordata Mill.)
goat willow (Salix caprea L.)
European ash (Fraxinus Excelsior L.)
other willow, species unknown (Salix sp.)
For further details of the data collection, measurements, and the content of the data files, see Hovi et al. (2022a) and README.pdf.