DOI: 10.5061/dryad.tb2rbp0cr
title: Seasonal and intra-canopy fates of absorbed photons across microclimatic gradients in Central Amazonian forests

description: We assessed seasonal and intra-canopy variations in leaf energy
 partitioning in central Amazonian forests with extensive in-canopy
 sampling and pulse amplitude modulated (PAM) chlorophyll fluorescence
 measurements. In order to cover seasonal variation of leaf
 microenvironments and energy partitioning, we compared measurements
 between dry (Jul.-Dec.) and wet (Jan.-Mar.) seasons in the TNF K67 site.
 The dataset includes the pathways of photon utilization for photochemistry
 (ΦPSII), heat dissipation (ΦNPQ), and fluorescence re-emission (ΦNO). Dry
 season field campaigns were conducted in 2019, 2021, and 2022, and a wet
 season campaign was conducted in 2023. We conducted pulse amplitude
 modulated (PAM) chlorophyll-a fluorescence measurements and sampling of
 microenvironmental variation at the leaf level with the MultispeQ (V2.0).
description: The research was conducted at the Tapajós National Forest (TNF)
 site, located near km 67 (K67, 02°51′S, 54°58′W) of the Santarém-Cuiabá
 highway, south of the city of Santarém (Pará, Brazil). It is an evergreen
 tropical forest on a well-drained infertile oxisol plateau, with a mean
 canopy height of approximately 40 to 45 m and a sub-dominant layer ranging
 from 15 to 30 m (with a mean of 28 m) (Hutyra et al., 2007; Hunter et al.,
 2015).  Individual leaf-level sampling approach
 employed advanced tree climbing techniques to access different canopy
 levels and measure in situ leaf-chlorophyll fluorescence with the
 MultispeQ.
description: # Seasonal and intra-canopy fates of absorbed photons across microclimatic
 gradients in Central Amazonian forests
 [https://doi.org/10.5061/dryad.tb2rbp0cr](https://doi.org/10.5061/dryad.tb2rbp0cr) ## Description of the data and file structure PAM ChlF measurements and sampling of microenvironmental variation at the leaf level were conducted with the MultispeQ (V2.0). Leaves fully expanded, mature, free of epiphylls and lacking necrotic and chlorotic patches were measured from the lower, middle, and upper regions of the crown using advanced tree climbing techniques to provide a representative sample. The MultispeQ replicates ambient photosynthetically active radiation (PAR) inside a leaf chamber, enabling quick measurements (approximately 30 seconds) of leaf-level PAR (µmol m-2 s-1), vapor pressure deficit (VPD), ΦNO, ΦPSII, and ΦNPQ while photosynthesis remains active. Height above ground level was measured with a tape extending to the ground to determine the height of each sampled leaf. ### Files and variables #### File: Ziccardi\_et\_al\_2025\_data\_NP.csv ##### Variables Description * Height:                                Height above ground level (m) * scientific:                             Scientific name * Season:                                Studied seasons (wet / dry) * Light.Intensity..PAR.:         Photosynthetically active radiation (µmol m-2 s-1) * VPD:                                     Vapor pressure deficit (kPa) * Phi2:                                    Yield of PSII photochemistry (ΦPSII) * PhiNPQ:                              Yield for dissipation through downregulation (ΦNPQ) * PhiNO:                                Yield of other non-photochemical losses (ΦNO) * qL_0:                                   Fraction of open PSII centers based on the "lake" model * NPQt_0:                              Non-photochemical quenching ## Code/software The data can be freely accessed using python and R.