Moisture dynamics during Coniophora puteana brown rot degradation of Scots pine sapwood

This dataset contains measurement data from the following publication: Belt T, Treu A, Möttönen V, Altgen M (2026) Moisture dynamics during Coniophora puteana brown rot degradation of Scots pine sapwood. International Biodeterioration & Biodegradation 209:106296, https://doi.org/10.1016/j.ibiod.2026.106296 Abstract Wood has many attractive material qualities, but it is susceptible to biological degradation by wood-decaying fungi. Moisture is one of the critical requirements for wood decay, but much remains unknown about moisture dynamics in decaying wood. To fill this knowledge gap, this study investigated moisture in Scots pine sapwood during decay caused by the brown rot fungus Coniophora puteana. Samples were exposed to decay in two time-series experiments; mass loss and moisture content were recorded over the course of decay, and the bound and free water populations in the samples were analysed using low-field nuclear magnetic resonance (LFNMR) relaxometry in both the decaying state and at full water saturation. Selected samples were also used for water vapour sorption measurements. The time-series decay tests showed that moisture content initially increased due to fungal activity but decreased over time when corrected for mass loss, contrary to the general belief that moisture content increases with decay. LFNMR revealed that bound water content increased on a decayed-mass basis in the decaying state and at saturation, but no increase was seen after correction for mass loss. Free water content followed gravimetric moisture content in the decaying state, but the saturated state measurements revealed an initial increase and subsequent decrease with mass loss. Degradation caused changes in hygroscopicity, but our data show that overall moisture content is regulated by fungal activity rather than by material properties. These findings highlight the complexity of water interactions during fungal degradation, offering valuable new insights into wood degradation mechanisms. Data description Methodological details can be found in the associated publication. The "IdentifiersAndMassData.csv" –file gives the sample identifiers and decay test mass data for all decayed and control samples from decay test 1 and decay test 2. The identifiers "test", "type", "time", and "replicate" are the decay test number (1 or 2), sample type (decayed or control), decay test time (0, 1, 2, 3, 4 or 5 weeks), and replicate number (1-10). Mass m1 is the initial dry mass, m2a-c are the decaying state wet mass (m2a immediately after the decay test, m2b immediately before LFNMR measurement, m2c immediately after LFNMR measurement), m3a-b are the saturated state wet mass (m3a immediately before LFNMR measurement, m3b immediately after LFNMR measurement), and m4 is the final dry mass after decay. The "LFNMR_RawData_Decaying.csv" –file gives the unprocessed, raw LFNMR T2 signal data for every sample from decay test 1 and decay test 2 measured in the decaying state. The "LFNMR_RawData_Saturated.csv" –file gives the unprocessed, raw LFNMR T2 signal data for every sample from decay test 2 measured in the water-saturated state. The "LFNMR_NNLS_Decaying.csv" –file gives the processed T2 distributions, obtained from the raw LFNMR signal data by regularised non-negative least squares (NNLS) fitting, for every sample from decay test 1 and decay test 2 measured in the decaying state. The "LFNMR_NNLS_Saturated.csv" –file gives the processed T2 distributions, obtained from the raw LFNMR signal data by regularised non-negative least squares (NNLS) fitting, for every sample from decay test 2 measured in the water-saturated state. The "LFNMR_Peaks_Decaying.csv" –file gives the LFNMR peak areas and peak times for every peak obtained from the NNLS-fitted T2 distributions for every sample from decay test 1 and decay test 2 measured in the decaying state. A1, A2, and A3 are the peak areas of peaks 1, 2, and 3, while t1, t2, and t3 and peak times of peaks 1, 2, and 3. The "LFNMR_Peaks_Saturated.csv" –file gives the LFNMR peak areas and peak times for every peak obtained from the NNLS-fitted T2 distributions for every sample from decay test 2 measured in the water-saturated state. A1, A2, and A3 are the peak areas of peaks 1, 2, and 3, while t1, t2, and t3 and peak times of peaks 1, 2, and 3. The ”Sorption” –folder contains sorption measurement data for the selected samples. The “Setup.csv” –file gives the positions of the samples in the sample carousel of the automated sorption balance, while the remaining files give the sample mass, target and read relative humidity, and target and read temperature over the sorption measurement sequence for a given sample. The file names correspond with the sample IDs given in the "IdentifiersAndMassData.csv" –file.