DOI: 10.5061/dryad.0vt4b8hc1
title: Effects of reduced precipitation and advanced spring phenology on intra- and interspecific competition between beech, oak and linden saplings

description: This repository contains physiological (leaf δ¹³C, nitrogen),
 phenological, and growth data from three temperate deciduous tree saplings
 grown in mesocosms under drought, warmer winters, or combined treatments.
 Saplings were cultivated in monocultures or two-species mixtures.
 Measurements span two growing seasons (2022–2023), including spring and
 autumn phenology, summer physiology (June/August), and growth assessments
 during winter.
description: # Effects of reduced precipitation and advanced spring phenology on intra-
 and interspecific competition between beech, oak and linden saplings
 Dataset DOI:
 [10.5061/dryad.0vt4b8hc1](https://doi.org/10.5061/dryad.0vt4b8hc1) ##
 Description of the data and file structure This repository contains
 physiological (leaf δ¹³C, nitrogen), phenological, and growth data from
 three temperate decidouos tree saplings grown in mesocosms under drought,
 warmer winters, or combined treatments. Saplings were cultivated in
 monocultures or two-species mixtures. Measurements span two growing
 seasons (2022–2023), including spring and autumn phenology, summer
 physiology (June/August), and growth assessments during winter. ### Files
 and variables #### File: Autumn_Phenology.txt **Description:** This file
 contains individual-level autumn phenology data for tree saplings grown in
 an experimental mesocosm setup. Each row represents a single sapling
 observed in a given year (2022–2023), with variables describing the
 experimental design (block, plot, compartment), species identity,
 competition and species composition, drought and warming treatments, and
 senescence timing. Phenological responses include the day of year (DOY) at
 50% and 80% senescence, indicators of premature senescence, and the
 fraction of premature leaf discoloration.  Empty cells were replaced with
 ‘n/a’. Plant losses occurred only rarely due to mortality. Most
 frequently, the onset of senescence was not recorded because premature
 discoloration occurred before phenological observations started in
 September. As a result, 50% senescence could not be assessed in these
 cases. ##### Variables * Block: Experimental mesocosm block (1-3) * Plot:
 Plot within block (1-6) * Compartment: Compartment within Plot (1-4) *
 Species: Investigated tree species * Number: Position of the sapling
 within the compartment * ID: Combination of Block, Plot, and Compartment *
 ID2: Combination of Block, Plot, Compartment, and Number * Competition:
 the competitor species of the compartment * Composition: the species
 composition of the compartment * Drought: drought treatment (yes, no) *
 Warming: warming treatment (yes, no) * Passive warming: passive warming
 treatment (yes, no) * Warming2: warming treatment (yes (neighbour=no), no
 (neighbour=yes), control (individuum and neighbour=no).  * Senescence50:
 DOY of 50% senescence * Senescence_80: DOY of 80% senescence * Year: Year
 (2022, 2023) * ID3: Combination of Block, Plot, Compartment, Number and
 Year * Premature Senescence: Premature senescence (yes=1, no=0) * Type:
 cultivation method before starting the experiment * Premature leaf
 discoloration: Fraction of premature leaf discoloration #### File:
 Meteo.txt **Description:** This file contains daily meteorological data
 recorded during the study period. Each row represents one calendar date
 and includes atmospheric temperature and vapor pressure deficit (VPD)
 measured 2 m above ground. Variables include daily mean, minimum, and
 maximum air temperature (°C) and VPD (kPa), along with corresponding date,
 month, and year information. ##### Variables * Date: Date * Year: Year *
 Month: Month * mean_AT: mean atmospheric temperature in °C, 2m above
 ground at a given date * min_AT: minimum atmospheric temperature in °C, 2m
 above ground at a given date * max_AT: maximum atmospheric temperature in
 °C, 2m above ground at a given date * mean_VPD: mean VPD in kPa, 2m above
 ground at a given date * min_VPD: minimum VPD in kPa,  2m above ground at
 a given date * max_VPD: minimum VPD in kPa, 2m above ground at a given
 date #### File: Sapling_Growth.txt **Description:** The dataset tracks the
 growth and experimental treatments of individual saplings across multiple
 years (2020–2024) in a controlled mesocosm setup. It combines information
 on sapling identity, experimental conditions, growth measurements, and
 biomass allocation. Empty cells were replaced with ‘n/a’. Plant losses
 occurred only rarely due to mortality. Two saplings were lost after
 excavation.  ##### Variables * Number: Serial number * Block: Experimental
 mesocosm block (1-3) * Plot: Plot within block (1-6) *
 Compartment: Compartment within Plot (1-4) * Species: Investigated tree
 species * Number: Position of the sapling within the compartment * Type:
 cultivation method before starting the experiment * ID: Combination of
 Block, Plot, and Compartment * ID2: Combination of Block, Plot,
 Compartment, and Number * Composition: the species composition of the
 compartment * Competition: the competitor species of the compartment *
 Drought: drought treatment (yes, no) * Warming: warming treatment (yes,
 no) * ID2: Combination of Block, Plot, Compartment, and Number * ID3:
 Combination of species, treatments and number * Passive warming: passive
 warming treatment (yes, no) * Warming2: warming treatment (yes
 (neighbour=no), no (neighbour=yes), control (individuum and neighbour=no).
 * H Winter 20/21: sapling height in winter 20/21(cm) * D Winter 20/21:
 sapling diameter in winter 20/21 (mm) * H Winter 21/22: sapling height in
 winter 21/22 (cm) * D Winter 21/22: sapling diameter in winter 21/22 (mm)
 * H Winter 22/23: sapling height in winter 22/23 (cm) * D Winter 22/23:
 sapling diameter in winter 22/23 (mm) * H Winter 23/24: sapling height in
 winter 23/24 (cm) * D Winter 23/24: sapling diameter in winter 23/24 (mm)
 * DI21: diameter increment 2021 (mm) * DI22: diameter increment 2022 (mm)
 * DI23: diameter increment 2023 (mm) * HI21: height increment 2021 (cm) *
 HI22: height increment 2022 (cm) * HI23: height increment 2023 (cm) *
 Total weight: total biomass (g) * Above-ground weight: biomass of the
 shoot (g) * Belowground weight: biomass of the root (g) * Root/Shoot:
 root/shoot ratio (-) #### File: Spring_Phenology.txt **Description:** This
 file contains individual-level spring phenology data for tree saplings
 grown in an experimental mesocosm setup. Each row represents a single
 sapling observed in a given year and includes variables describing the
 experimental design (block, plot, compartment), species identity, species
 composition and competition, drought and warming treatments, and
 cultivation method prior to the experiment. Phenological development is
 recorded as dates of four spring phenological stages, along with the
 number of days required to progress from stage 2 to stage 4. Empty cells
 were replaced with ‘n/a’. Plant losses occurred only rarely due to
 mortality. In the phenological assessments, individual stages were
 occasionally missed. Phenological stages are reported as "Day of the
 year (DOY)" Phenological assessments were conducted following the
 protocol described in Vitasse, Y. (2013) Ontogenic changes rather than
 difference in temperature cause understory trees to leaf out earlier. *New
 Phytologist,* 198(1), 149-155.
 [https://doi.org/10.1111/nph.12130](https://doi.org/10.1111/nph.12130).
 ##### Variables * Block: Experimental mesocosm block (1-3) * Plot: Plot
 within block (1-6) * Compartment: Compartment within Plot (1-4) *
 Species: Investigated tree species * Number: Position of the sapling
 within the compartment * ID: Combination of Block, Plot, and Compartment *
 ID2: Combination of Block, Plot, Compartment, and Number *
 Composition: the species composition of the compartment * Competition: the
 competitor species of the compartment * Drought: drought treatment (yes,
 no) * Warming: warming treatment (yes, no) * Passive warming: passive
 warming treatment (yes, no) * Warming2: warming treatment (yes
 (neighbour=no), no (neighbour=yes), control (individuum and neighbour=no).
 * Comments: Comments * Stage 1: Phenological stage 1 (DOY) * Stage 2:
 Phenological stage 2 (DOY) * Stage 3: Phenological stage 3 (DOY) * Stage
 4: Phenological stage 4 (DOY) * S2-S4: Days required from spring
 phenological stage 2 to 4.  * Year: Year * Type: cultivation method before
 starting the experiment #### File: Sapling_Physiology.txt
 **Description:** This file contains physiological and stable isotope
 measurements of tree saplings grown in an experimental mesocosm setup.
 Each row represents a single sapling sampled during the growing season
 (June or August) in 2022 or 2023. Variables describe species identity,
 experimental design and treatments (competition, species composition,
 drought, warming, and passive warming), cultivation method prior to the
 experiment, and leaf physiological traits, including carbon and nitrogen
 stable isotope ratios, elemental concentrations, and C/N ratio. #####
 Variables * Block: Experimental mesocosm block (1-3) * ID:  Combination of
 Block, Plot, Compartment, and Number * ID2:  Combination of Block, Plot,
 Compartment, and Number * Species: Investigated tree species *
 Competition: the competitor species of the compartment * Composition: the
 species composition of the compartment * Warming: warming treatment (yes,
 no) * Passive.warming: passive warming treatment (yes, no) *
 Drought: drought treatment (yes, no) * Sampling: Season of the sampling
 (June, August) * Year: Year (2022, 2023) * d13C: δ^13^C of the bulk leaf *
 % C: Carbon percentage of the bulk leaf * d15N: δ^15^N of the bulk leaf *
 % N: Nitrogen percentage of the bulk leaf * C/N: C/N-ratio of the bulk
 leaf * Plot: description how the tree saplings are growing (monoculture,
 mixture) * Type: cultivation method before starting the experiment ##
 Code/software A data editor is sufficient to view the data.