Tree leaf and needle spectra for three sites in northern and central Europe

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.本数据集包含叶片和针叶样品的反射光谱与透射光谱（reflectance and transmittance spectra），采集于2019年和2020年的生长旺季临近时段，采样点位于北欧与中欧的三处研究区域：芬兰Hyytiälä（61°51'N，24°18'E）、爱沙尼亚Järvselja（58°17'N，27°19'E）以及捷克共和国Bílý Kříž（49°30'N，18°32'E）。 上述光谱数据已发表于Hovi等人2022年的研究：Hovi, A., Lukeš, P., Homolová, L., Juola, J., Rautiainen, M. (2022a). 《欧洲范围内挪威云杉针叶光谱的地理变异性微弱》，Silva Fennica，第56卷第2期，文章编号10683，https://doi.org/10.14214/sf.10683。若使用本数据集，请同时引用上述发表文献以及Mendeley数据集：Hovi, A., Juola, J., Lukeš, P., Homolová, L., Rautiainen, M. (2022b). 《北欧与中欧三处样地的树木叶片及针叶光谱》，Mendeley Data, V1，https://doi.org/10.17632/t5f554s7cn.1。 针对下述物种与研究样地，我们在每个样地选取3株独立个体进行采样。每株树木分别采集3份冠顶（主要为光照充足）的叶片样品，以及3份冠底（主要为遮阴）的叶片样品。对于常绿针叶树（evergreen conifers），我们同时采集当年生和一年生针叶，使样品数量翻倍。针对每株树木，我们记录了其自身以及周边林分的特征（树高、直径）。 采样涵盖的物种包括：挪威云杉（Picea abies (L.) H. Karst，所有样地均有分布）；欧洲赤松（Pinus sylvestris L.，所有样地均有分布）；Hyytiälä与Järvselja样地的垂枝桦（Betula pendula Roth）；Hyytiälä与Järvselja样地的欧洲桤木（Alnus glutinosa (L.) Gaertn.）；Järvselja样地的欧洲山杨（Populus tremula L.）。 此外，我们还对Järvselja样地的5种稀有物种进行了光谱测量。这些数据未在Hovi等人2022a的研究中发表，本次收录旨在完善数据集的全面性。针对这些稀有物种，我们仅为每个物种选取1株个体，并仅采集冠顶的叶片样品，每株树采集3份样品。所有待测树木均为幼树（树高不超过5米），未记录其自身及周边林分的特征。上述稀有物种包括：美洲榛（Corylus avellana L.）、小叶椴（Tilia cordata Mill.）、山羊柳（Salix caprea L.）、欧洲白蜡（Fraxinus excelsior L.）以及未知种柳树（Salix sp.）。 关于数据采集、测量方法以及数据文件内容的更多细节，请参阅Hovi等人2022a的研究以及README.pdf文件。