The Tervuren xylarium Wood Density Database (TWDD)
Data files
Dec 18, 2025 version files 3.90 MB
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OvenDryingExperiment.csv
25.64 KB
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README.md
4.25 KB
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TWDD_code.R
72.86 KB
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TWDD.xlsx
3.80 MB
Abstract
Wood density is a key plant property, indispensable for estimating forest biomass. Yet, despite tropical regions' substantial contributions to global tree diversity and carbon cycling, they remain underrepresented in wood density datasets such as the CIRAD and Global Wood Density Database (GWDD). To address this gap, we present the ‘Tervuren xylarium Wood Density Database’ (TWDD), containing 13,332 samples from 2,994 species, 1,022 genera, and 156 plant families across six continents (72% from Africa). TWDD offers direct measurements of oven-dry (oven-dry mass/oven-dry volume, all samples), air-dry (air-dry mass/air-dry volume, 6,408 samples), green (green mass/green volume, 1,657 samples), and basic wood density (oven-dry mass/green volume, 1,686 samples). Basic density was estimated for the remaining 11,646 samples via conversion from oven-dry density. TWDD closes a substantial wood density data gap, especially in Africa, adding 1,164 new species, 160 new genera, and 8 new plant families not included in GWDD or CIRAD datasets. The TWDD provides a critical resource for advancing research on forest community dynamics, ecosystem functioning, carbon cycling, and trait-based ecology worldwide.
Dataset DOI: 10.5061/dryad.31zcrjf1k
Description of the data and file structure
The ‘Tervuren xylarium Wood Density Database’ (TWDD) contains 13,332 samples from 2,994 species, 1,022 genera, and 156 plant families across six continents (72% from Africa). TWDD offers direct measurements of oven-dry (oven-dry mass/oven-dry volume, all samples), air-dry (air-dry mass/air-dry volume, 6,408 samples), green (green mass/green volume, 1,657 samples), and basic wood density (oven-dry mass/green volume, 1,686 samples). Basic density was estimated for the remaining 11,646 samples via conversion from oven-dry density. TWDD closes a substantial wood density data gap, especially in Africa, adding 1,164 new species, 160 new genera, and 8 new plant families not included in GWDD or CIRAD datasets.
Files and variables
File: OvenDryingExperiment.csv
Description: This csv file contains the data of the oven-drying time experiment, with the mass, volume, and density of wood samples in air-dry conditions (columns: m_airdry, V_airdry, and WD_airdry) and after oven-drying for 24h (columns: m_ovendry_24h, V_ ovendry_24h, and WD_ovendry_24h) and 48h (columns: m_ovendry_48h, V_ovendry_48h, and WD_ovendry_48h). This was shown for each of the four classes representing low and high wood density and volume (column: Category).
Variables
- Category: The category of wood density (high or low) and sample volume (high or low)
- Tw: The unique identified number of the Tervuren xylarium.
- m_airdry: Air-dry mass of the wood (g).
- m_ovendry_24h: Oven-dry mass of the wood after 24h oven-drying at 104°C (g).
- m_ovendry_48h: Oven-dry mass of the wood after 48h oven-drying at 104°C (g).
- V_airdry: Air-dry volume of the wood (cm^3).
- V_ovendry_24h: Oven-dry volume of the wood after 24h oven-drying at 104°C (cm^3).
- V_ovendry_48h: Oven-dry volume of the wood after 48h oven-drying at 104°C (cm^3).
- WD_airdry: Air-dry wood density of the wood (g/cm^3).
- WD_ovendry_24h: Oven-dry volume of the wood after 24h oven-drying at 104°C (g/cm^3).
- WD_ovendry_48h: Oven-dry volume of the wood after 48h oven-drying at 104°C (g/cm^3).
File: TWDD_code.R
Description: The R file creates all figures and statistics reported in this paper. To generate a map of the provinces of the Democratic Republic of Congo, we used shapefiles downloaded from Download Democratic Republic of the Congo GIS data. Furthermore, to assess the consistency of our wood density data with other databases, we used the Global Wood Density Database (https://doi.org/10.5061/dryad.234) and CIRAD datasets (https://doi.org/10.18167/DVN1/KRVF0E and https://doi.org/10.18167/DVN1/CDHU51).
File: TWDD.xlsx
Description: The TWDD dataset is stored in an Excel file with the following three sheets:
- ‘Legend’: contains a description of the columns of the dataset.
- ‘TWDD’: contains the wood density data and metadata.
- ‘Overview Table’: contains an overview of the regional geographic and taxonomic coverage of the dataset.
Code/software
R version 4.4.2
R working packages: readxl, ggplot2, ggpubr, ggpmisc, EnvStats, tidyr, dplyr, readr, sp, sf, tidytext, stringr, viridis, ggh4x, ggridges, smatr, WorldFlora, cowplot, forcats, Metrics
Access information
Data was derived from the following sources:
- Shapefiles for mapping provinces in the Democratic Republic of the Congo: Download Democratic Republic of the Congo GIS data
- Wood density data from the Global Wood Density Database (https://doi.org/10.5061/dryad.234) and the CIRAD datasets (https://doi.org/10.18167/DVN1/KRVF0E and https://doi.org/10.18167/DVN1/CDHU51).