Data and code from: Height does not impair the hydraulic system of the tallest tropical Dipterocarp trees
Data files
Jun 30, 2026 version files 191.60 KB
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analysis.r
17.28 KB
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dendrometerData.xlsx
142.53 KB
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README.md
15.58 KB
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traitsSummaryTable.xlsx
16.21 KB
Abstract
Half the above-ground biomass in forests is stored in a disproportionately small number of very tall trees. These giants are predicted to be vulnerable to drought-induced damage because it is assumed height limits their hydraulic system. We evaluated whether the world’s tallest tropical tree species – South-East Asian dipterocarps – are hydraulically limited by height. Taller trees fully compensated for the more negative xylem pressures caused by tree height through adjusting vessel anatomy and leaf hydraulic traits, and they suffered no height-related loss in growth during a severe drought. Therefore, height does not make the hydraulic systems of the world’s tallest tropical tree species more vulnerable, and their performance appears as resilient as that of smaller individuals in response to drought.
Dataset DOI: 10.5061/dryad.d51c5b0j4
Description of the data and file structure
Trunk diameter growth rate of 42 dipterocarps trees in the Kabili-Sepilok Forest Reserve, Borneo, monitored during a reference and a strong ENSO year. We used point dendrometers (D1, TOMST, Czech Republic) installed at breast height or above the buttresses to monitor micrometric changes in tree diameter.
Files and variables
File: dendrometerData.xlsx
growthRateTimeSeries spreadsheet: daily growth rates filtered and averaged of a 14 days period.
growthRateReduction spreadsheet: average growth rate over specific periods (see detailed methods in the manuscript)
growthRateTimeSeries spreadsheet
| Field | notes | units | obs |
|---|---|---|---|
| date | date growth rate refers to | dd-mm-yyyy | |
| treeID | a string of plot, plot number, suplot, quadrat, tree ID | ||
| species | studied dipterocarp species | latin name | |
| treeHeight | height of the tree | m | |
| treeDiameter | diameter of the tree at breast height or above the butress | m | |
| SWC | soil water content | % | |
| RBGR | relative growth rate | mm2 m-2 day-1 | |
| growthRateReduction spreadsheet | |||
| Field | notes | units | |
| treeID | a string of plot, plot number, suplot, quadrat, tree ID | ||
| species | studied dipterocarp species | latin name | |
| treeHeight | height of the tree | m | |
| treeDiameter | diameter of the tree at breast height or above the butress | m | |
| GR_REF | growth rate during the reference year | µm day-1 | |
| GR_ENSO | growth rate during the ENSO year | µm day-1 | |
| droughtGrowthReduction | growth reduction during the ENSO year in relation to the reference year | % | 100*GR_enso/GR_reference |
| GR_recoveryREF | growth rate during the recovery period of the reference year | µm day-1 | |
| GR_recoveryENSO | growth rate during the recovery period of the ENSO year | µm day-1 | |
| recoveryGrowthReduction | growth reduction during the recovery period of the ENSO year in relation to the same period of the reference year | % | 100*GR_recoveryENSO/GR_recovery_reference |
note: growth rates refer to trunk diametric growth rate
File: traitsSummaryTable.xlsx
Summary of the hydraulic traits data used in the manuscript. Average and standard deviation of measured trait values by species and position of the branch within the crown.
| Trait | Unit | Description | |
|---|---|---|---|
| Water status | Ψmd | MPa | Midday water potential |
| Ψmdg | MPa | Gravity compensated water potential (Ψmd – 0.0098 Branch height) | |
| Ψmm | MPa | Midmorning (9-10h) water potential | |
| Ψpd | MPa | Predawn water potential | |
| Leaf | TLPΨ | MPa | Turgor loss point |
| pressure-volume | OP | MPa | Cell osmotic potential at full turgor |
| relations | E | MPa | Bulk leaf modulus of elasticity |
| TLPRWC | unitless | Relative water content at TLP | |
| Embolism | P50leaf | MPa | Water potential when branch or leaf loses 50% or 88% of its water transport capacity, as estimated from 50% increase in air extraction (branch) and 50% embolized area (leaf) |
| resistance | P88leaf | MPa | |
| P50wood | MPa | ||
| P88wood | MPa | ||
| Safety margins | HSMtlp | MPa | Hydraulic safety margin, difference between Ψmd and the point when the leaf loses turgor (HSMtlp) or 50% water transport capacity (HSMleaf) and when the branch xylem loses 50% water transport capacity (HSMwood) |
| HSMleaf | MPa | ||
| HSMwood | MPa | ||
| Anatomy and | Ksp | kg m^-1^ s^-1^ MPa^-1^ | Potential xylem hydraulic specific conductivity |
| hydraulics | Ksleaf | kg m^-2^ s^-1^ MPa^-1^ | Potential leaf specific hydraulic conductivity |
| Vessel diameter | µm | Mean xylem vessel diameter | |
| Vessel density | mm^-2^ | Number of xylem vessels per unit area | |
| LA:SA | m2 cm^-2^ | Leaf-to-sapwood area ratio | |
| Leaf traits | Leaf size | cm2 | Area of the leaf |
| Leaf thickness | mm | Thickness of leaf lamina | |
| LMA | g m^-2^ | Leaf mass per area | |
| Wood traits | WD | g cm^-3^ | Branch wood density |
| Wood SWC | g cm^-3^ | Branch wood saturated water content |
File: analysis.r
Code used for the data analysis.
Trait data can be found on UKRI EIDC (DOI: 10.5285/6ECFD160-4740-491E-A8B3-8CBB3A4C8701).
Code/software
LibreOffice, R, or other software capable of reading Microsoft Excel spreadsheets
The code used for the analysis is provided with this dataset (file "analysis.r")