Project name: Joint project between CSIC and Estonian research institutions (Spanish conifer project) Citations of the published research derived from these data: Kuusk, V., Niinemets, Ü. & Valladares, F. (2018) Structural controls on photosynthetic capacity through juvenile-to-adult transition and needle aging in Mediterranean pines. Functional Ecology xx, In Press. and Kuusk, V., Niinemets, Ü. & Valladares, F. (2018) A major trade-off between structural and photosynthetic investments operative across plant and needle ages in three Mediterranean pines. Tree Physiology xx, In Press, doi.org/10.1093/treephys/tpx1139. Contact information for authors regarding data collection and analyses: Ülo Niinemets and Vivian Kuusk (Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1 Tartu 51014, Estonia, vivian.kuusk@emu.ee and ylo.niinemets@emu.ee) File name: Data-from-Kuusk-et-al-Functional_Ecology-2018-Leaf-structural-and-photosynthetic-characteristics-in three-conifer-species.ods (Open Office ODF spreadsheet format, saved with Libre Office Calc 4.4) The column heads provide full definition of the traits and measurement units. Description of all data processing steps and analyses are provided in the original publication. The data file includes all the needle traits used (each data lines corresponds to an individual replicate measurement plant (juveniles) or branch (adults)). The traits are grouped as: Meta information (columns A-E, including species name, tree age class (juvenile vs. adult), needle age and measurement year as explained in the original publications) Needle ultrastructural characteristics (columns F-Q, measurements using transmission electron microscopy and derived traits) Tissue fractional composition (volumetric fractions in the needle cross-section, columns R-Z) Needle "macrostructural" characteristics (columns AA-AL, measurements using light microscopy, and callipers, associated derived traits and mass-based ratios) Needle chemical characteristics (columns AM-AQ) Needle photosynthetic characteristics (columns AR-BA) Relationships of data to the accompanying publication (Kuusk et al. , Functional Ecology 2018) Table 1: columns AR-AT and AY-BA (two way ANOVA for adult vs. juveniles only includes data for current-year needles; two way ANOVA for different aged adult needles only includes adult needles) Table 2: columns AR-AT and AY-BA (physiological characteristics) and columns R-U, Y, AH, AJ-AL, AN and AQ (structural and chemical characteristics) Figure 1: columns AU-AX Figure 2: columns AV, AX and U Figure 3: columns AU-AX and AN and AQ Supplementary Figure 1: Columns AU-BA