Content
- Wood and the Romans
- Interdisicplinary data sources
- Dendroprovenance
- Network analysis of tree-ring data
- Archaeological interpretation
- R-package: dendroNetwork
- Conclusions
Relating Roman Rings: an open and reproducible approach to understanding provenance patterns of wood using networks
05 May, 2025
Wood: primary resource
- Growing in woodlands
- Primary (renewable) resource, for e.g.
- Construction
- Transport
- Heating
- Tools
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Roman wood and timber
Problem definition
- Many finds of wood from Roman period
- Archaeological context known
- Provenance of wood unknown
Main research question
- How was the procurement of wood organised in the German provinces of the Roman empire during first four centuries AD?
Data sources
(Source: Visser 2025, fig. 03.02)
Dendrochronological data: “bias”
(Source right figure: Visser 2025, fig. 03.17) (Source left figure: Visser 2025, fig. 03.10)
Sparse big data:
- Mainly oak
- Spatial
- Temporal
Research intensity (Netherlands)
(Source: Visser 2025, fig. 03.19)
Tree-ring formation
- Annual ring of wood around tree
- Tree-ring width depends on
- Soil
- (micro)Climate
- Local factors
- Disturbance
- Growth season: spring and summer
Life history of archaeological wood
(Source: Visser 2025, fig. 03.05)
Dendroprovenance
Provenance of wood based on comparison tree-ring curves with (regional) chronologies
Problems
- Often based on single measure
- Comparison individual curves
- Complex with large datasets
- Clustering problems common interval
Solution: network analyses
Dendrochronological networks
- Nodes: Site chronologies (tree-ring data)
- Edges: statistical similarity
- Correlation (r ≥ 0,5)
- Overlapping tree rings (n ≥ 50)
- SGC (improved statistic, formerly Gleichläufigkeit: ≥ 70% (see Visser 2021a))
- Probability of exceedence (p <= 0.0001)
Provenance in network
- Closer in network = similar growth conditions
- Communities share growth conditions
- Assess spatial distances
- Contexts
(Figure source: Visser 2025, fig. 09.03)
Provenance and transported distances
Provenance of wood and the Roman economy
(Source: Visser 2025, fig. 10.04)
Open Science in research
Publications: Open Access
(Visser 2021b; Visser and Vorst 2022b)
Scripts and data: Open
(Visser and Vorst 2022a; Visser 2022)
Everything open and accessible
- R-Scripts available
- Comments available
Hard to use for others(!)
Package: do we need another?
Existing packages for dendrochronology.
dendroNetwork and its position in relation to other dendrochronological packages.
rOpenSci
- Creating technical infrastructure in the form of carefully vetted, staff and community-contributed R software tools that lower barriers to working with scientific data sources on the web
- Making the right data, tools and best practices more discoverable
- Creating social infrastructure through a welcoming and diverse community
- Promoting advocacy for a culture of data sharing and reusable software
- Building capacity of software users and developers and fostering a sense of pride in their work
Package
- Creating functions
- Converting scripts to functions
- Naming functions (snake_case, snake_case, etc)
- Simple programming (loops, variables, etc)
- Creating documentation
- Manual pages
- Vignettes
- Creating tests (input, results, etc)
- Continous integration: https://devguide.ropensci.org/pkg_ci.html
- usethis package
- Github Actions
Package: Review
- Github issue: https://github.com/ropensci/software-review/
- Developers test your package
- Feedback
- Improvement of code
- Improvement of documentation
- Open peer review
Package: Dissemination
- Source: https://github.com/ropensci/dendroNetwork/
- Documentation: https://docs.ropensci.org/dendroNetwork/
- CRAN: https://cran.r-project.org/package=dendroNetwork
- Blog: https://ropensci.org/blog/2024/06/06/from-scripts-to-package/
- Social media: Mastodon, LinkedIn, Facebook.
- Present at CAA2025 in Athens
- Write paper (still to publish)
References
Source of these slides: https://github.com/RonaldVisser/RelatingRomanRings_CAA2025 https://doi.org/10.5281/zenodo.15342407
Visser, Ronald M. 2021a. “On the Similarity of Tree-Ring Patterns: Assessing the Influence of Semi-Synchronous Growth Changes on the Gleichläufigkeitskoeffizient for Big Tree-Ring Data Sets.” Archaeometry 63 (1): 204–15. https://doi.org/10.1111/arcm.12600.
———. 2021b. “Dendrochronological Provenance Patterns. Network Analysis of Tree-Ring Material Reveals Spatial and Economic Relations of Roman Timber in the Continental North-Western Provinces.” Journal of Computer Applications in Archaeology 4 (1): 230–53. https://doi.org/10.5334/jcaa.79.
———. 2022. “Dendrochronological Provenance Patterns. Code and Data of Network Analysis of Tree-Ring Material.” https://doi.org/10.5281/zenodo.10200361.
———. 2024. “Securing Transport of Wood over Water on the Roman Rhine.” In, edited by H. van Enckevort, Mark Driessen, E. P. Graafstal, Tom Hazenberg, Tatiana Ivleva, and Carol van Driel-Murray, 135–41. Leiden: Sidestone Press. https://doi.org/10.59641/mm723py.
———. 2025. “Relating Roman Rings. An Interdisciplinary Study Using Archaeology, Data Science and Tree Rings to Understand Timber Provision in the German Provinces of the Roman Empire.” PhD thesis, Amsterdam. https://doi.org/10.5463/thesis.1062.
Visser, Ronald M., and Yardeni Vorst. 2022a. “Analyses, Data and Figures Related to: "Connecting Ships: Using Dendrochronological Network Analysis to Determine the Wood Provenance of Roman-Period River Barges Found in the Lower Rhine Region and to Visualise Patterns of Wood Use".” https://doi.org/10.5281/zenodo.7243539.
———. 2022b. “Connecting Ships: Using Dendrochronological Network Analysis to Determine the Wood Provenance of Roman-Period River Barges Found in the Lower Rhine Region and Visualise Wood Use Patterns.” International Journal of Wood Culture 3 (1-3): 123–51. https://doi.org/10.1163/27723194-bja10014.