ronaldvisser/provenancenetworks

Network analysis of Roman tree-ring data. Published in the Journal of Computer Applications in Archaeology (JCAA)

Dendrochronological Provenance Patterns. Code and Data of Network Analysis of Tree-Ring Material

This repository consists of:

CompareSeries:

• R-Project to compare tree ring series and write the resuls to a database

ITRDB_dendrobox_analyses

• R-Project that uses the data from dendrobox (https://github.com/cszang/dendrobox) and the ITRDB to show the use of networks for dendroprovenance based on data from living trees

Network_analysis

• R-Project for the comparison of tree ring data and the creation of networks. COmmunity detection within the networks is also present.

SupplementaryTables:

• Tables and data to make research reproducible

See also https://github.com/RonaldVisser/SGC

All CSV files larger than 100MB were split using https://sourceforge.net/projects/splitcsv/

Published as

Visser, R.M., 2021. 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), pp.230–253. DOI: http://doi.org/10.5334/jcaa.79

Abstract: Most dendrochronological provenance studies rely on simple comparisons between tree-ring series based on a single variable. In addition, most fail to consider the complex system of relations that is the result of the variables that influence tree-ring patterns. Network analysis is a solution to this problem, because it allows to both visualize and analyse the complex (provenance) relations of tree-ring series as a whole. A network makes it impossible to ignore existing (statistical) relations between tree-ring series. Although networks can be build using any (combination of) similarity measure(s), in this study a combination of the Synchronous Growth Changes (SGC), its related probability of exceedance (p), correlation (r) and overlap define the edges. This paper focusses on networks with site chronologies as nodes, although individual tree series or a combination thereof with site chronologies are also possible. A combination of these can also help to refine the (archaeological) interpretation. The location of any tree-ring series in a network reflects its provenance. Material that is placed closer together in the network has similar growth patterns and is generally from the same region. Therefore, network communities reflect wood that has a similar provenance. If tree-ring material found on different spatial locations but in close proximity in the network, this indicates that wood has been moved. To determine which wood has been used, a combination of archaeological and spatial arguments is used. The method is sound, simple and gives insight in the complexity of all tree-ring relations in a simple diagram. The resulting patterns show that the majority of wood was obtained in the region where it was used, but that transport of wood in the Roman period did take place. Three scales are defined to describe the Roman wood economy: local, provincial and imperial. While transport of wood over long distances is attested for both military and civilian sites (provincial and imperial scale), it seems that wood that was transported beyond the provincial borders was only used in civilian sites (imperial scale). The combination of network science, dendrochronology and archaeology is a powerful method to understand patterns in the Roman timber economy.