| Table 1. Summary of leaf and needle samples collected for this study (HY-JS-BK 2019–20 campaign). The site codes refer to Hyytiälä (HY), Järvselja (JS), and Bílý Kříž (BK). Scientific names of the species (reported in the main text) follow the nomenclature in https://www.tropicos.org. | |||||
| Species | Sites | Number of trees per site | Tree heights at each site [m] | Number of samples per tree | Total number of samples |
| Norway spruce | HY, JS, BK | 3 | 19–25, 7–14, 7–35 | 12 | 108 |
| Scots pine | HY, JS | 3 | 14–17, 8–24 | 12 | 72 |
| Silver birch | HY, JS | 3 | 16–20, 6–13 | 61 | 36 |
| Black alder | JS | 3 | 5–12 | 61 | 18 |
| European aspen | JS | 3 | 5–13 | 61 | 18 |
| 1 Deciduous broadleaved trees had only one leaf age cohort. Therefore, the number of samples per tree is half of that measured for conifers. | |||||
Fig. 1. Variation in albedo spectra of Norway spruce top-of-canopy needles within and between measurement campaigns. CV denotes coefficient of variation. The colored lines show campaign-specific spectra, the thick black line shows between-campaign CV, and the gray area shows min-max of individual spectra among all campaigns. Top row shows full spectra, and bottom row close-ups of the visible wavelength region. The results are shown separately for current-year (c0, left column) and one-year-old (c1, right column) needles.
Fig. 2. Variation in albedo spectra of Norway spruce top-of-canopy needles within and between study sites observed in the new HY-JS-BK 2019–20 campaign. CV denotes coefficient of variation. The colored lines show site-specific spectra, the thick black line shows between-site CV, and the gray area shows min-max of individual spectra among all sites. Top row shows full spectra, and bottom row close-ups of the visible wavelength region. The results are shown separately for current-year (c0, left column) and one-year-old (c1, right column) needles.
Fig. 3. Variation in albedo spectra of top-of-canopy foliage within- and between tree species. CV denotes coefficient of variation. The right column shows a close-up of the visible wavelength region. The symbol c0 denotes current-year, and c1 one-year-old needles.