Dr. Brendan Nicholas Marais

Research interests

• Wood protection
• Wood degradation
• Durability and service-life of wood and wood-based products
• Moisture monitoring of wooden elements

Dissertation

• Durability of Wood in Ground Contact: Modelling the Effect of Biotic and Abiotic Factors
• Supervisor: PD Dr. Christian Brischke



Projects

• HyLight - Energy-efficient production of complex-shaped, multifunctional and recyclable lightweight products made of wood and bioplastics using automatic injection-moulding machines
• WoodLCC - Enabling robust and precise Life-Cycle-Costing (LCC) based on input from novel models for detailed service life performance specification for wooden components and buildings
• CEMWOGEO - Cement coating of wood for geotechnical applications
• CemSleeper - Cement coating of wood for railway applications
• CLICK DESIGN - Delivering fingertip knowledge to enable service life performance specification of wood




Teaching

Supervision of student theses (for reasons of data protection law, the authors names are withheld)

Master theses

2021

• The potential of detecting wood decay using photoacoustic imaging: a review

2020

• Impact of soil temperature on the decay rate of European beech wood



Bachelor theses

2020

• Studies on the effect of soil type on the decay rate of selected wood species

2019

• Impact of soil water-holding capacity and soil moisture content on decay rate of selected timbers



Project theses

2021

• Cement treatment of wood for geotechnical use - An electron microscopic analysis

2020

• The effect of a cement coating on European Beech and Norway Spruce wood - studies into fungal durability and brittleness



Publications


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  2024 (2)

Decay hazard of wood exposed in-ground in changing climates in Germany. van Niekerk, P. B.; Marais, B. N.; Alfredsen, G.; and Brischke, C. Wood Material Science & Engineering, 0(0): 1–8. 2024. Publisher: Taylor & Francis _eprint: https://doi.org/10.1080/17480272.2024.2408650
Paper   doi   link   bibtex   abstract  

@article{van_niekerk_decay_2024,
	title = {Decay hazard of wood exposed in-ground in changing climates in {Germany}},
	volume = {0},
	issn = {1748-0272},
	url = {https://doi.org/10.1080/17480272.2024.2408650},
	doi = {10.1080/17480272.2024.2408650},
	abstract = {The ability to identify locations that have a high risk of fungal decay is important for service life planning and analysing changes in risk can help inform scenarios where climate change may shift some areas into states that are more suitable for decay. The ERA5-Land database was used to obtain soil moisture and temperature data, which was applied in a dose–response model for in-ground wood decay. Dose was used as an indicator of decay risk and to produce hazard maps over Germany for the past two climate normals (1963–1992 and 1993–2022). There was an increase of 3.16 dose days over Germany. Brandenburg and Mecklenburg-Vorpommern, had the highest decay risk in both climate normals and southern states experienced the lowest decay risk. In Germany, larger dose increases were seen in central to southern latitude regions and mid to high altitudes. With further climate change, conditions that are most suitable for in-ground wood decay may shift to locations that previously did not experience such risk. It is important to be informed of the durability requirements of wood products in areas where increased resistance may be required.},
	number = {0},
	urldate = {2024-12-05},
	journal = {Wood Material Science \& Engineering},
	author = {van Niekerk, Philip B. and Marais, Brendan N. and Alfredsen, Gry and Brischke, Christian},
	year = {2024},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/17480272.2024.2408650},
	keywords = {fungi, dose–response model, service life, Climate change, use class 4},
	pages = {1--8},
	file = {Full Text PDF:/home/maicher/Zotero/storage/NSWG5IPI/van Niekerk et al. - Decay hazard of wood exposed in-ground in changing.pdf:application/pdf},
}

The ability to identify locations that have a high risk of fungal decay is important for service life planning and analysing changes in risk can help inform scenarios where climate change may shift some areas into states that are more suitable for decay. The ERA5-Land database was used to obtain soil moisture and temperature data, which was applied in a dose–response model for in-ground wood decay. Dose was used as an indicator of decay risk and to produce hazard maps over Germany for the past two climate normals (1963–1992 and 1993–2022). There was an increase of 3.16 dose days over Germany. Brandenburg and Mecklenburg-Vorpommern, had the highest decay risk in both climate normals and southern states experienced the lowest decay risk. In Germany, larger dose increases were seen in central to southern latitude regions and mid to high altitudes. With further climate change, conditions that are most suitable for in-ground wood decay may shift to locations that previously did not experience such risk. It is important to be informed of the durability requirements of wood products in areas where increased resistance may be required.

Acetyliertes Buchen-Furnierlagenholz für tragende Anwendungen: Furniere und Verklebung. Slabohm, M.; Emmerich, L.; Marais, B. N.; Brischke, C.; and Militz, H. In Deutsche Holzschutztagung 2024, pages 182–193, Dresden, 2024. IHD
link   bibtex  

@inproceedings{slabohm_acetyliertes_2024,
	address = {Dresden},
	title = {Acetyliertes {Buchen}-{Furnierlagenholz} für tragende {Anwendungen}: {Furniere} und {Verklebung}},
	language = {de},
	booktitle = {Deutsche {Holzschutztagung} 2024},
	publisher = {IHD},
	author = {Slabohm, Maik and Emmerich, Lukas and Marais, Brendan Nicholas and Brischke, Christian and Militz, Holger},
	year = {2024},
	pages = {182--193},
}

  2023 (2)

Modelling in-ground wood decay using time-series retrievals from the 5th European climate reanalysis (ERA5-Land). Marais, B. N.; Schönauer, M.; van Niekerk, P. B.; Niklewski, J.; and Brischke, C. European Journal of Remote Sensing, 56(1): 2264473. December 2023. Publisher: Taylor & Francis _eprint: https://doi.org/10.1080/22797254.2023.2264473
Paper   doi   link   bibtex   abstract  

@article{marais_modelling_2023,
	title = {Modelling in-ground wood decay using time-series retrievals from the 5th {European} climate reanalysis ({ERA5}-{Land})},
	volume = {56},
	issn = {null},
	url = {https://doi.org/10.1080/22797254.2023.2264473},
	doi = {10.1080/22797254.2023.2264473},
	abstract = {This article presents models to predict the time until mechanical failure of in-ground wooden test specimens resulting from fungal decay. Historical records of decay ratings were modelled by remotely sensed data from ERA5-Land. In total, 2,570 test specimens of 16 different wood species were exposed at 21 different test sites, representing three continents and climatic conditions from sub-polar to tropical, spanning a period from 1980 until 2022. To obtain specimen decay ratings over their exposure time, inspections were conducted in mostly annual and sometimes bi-annual intervals. For each specimen’s exposure period, a laboratory developed dose–response model was populated using remotely sensed soil moisture and temperature data retrieved from ERA5-Land. Wood specimens were grouped according to natural durability rankings to reduce the variability of in-ground wood decay rate between wood species. Non-linear, sigmoid-shaped models were then constructed to describe wood decay progression as a function of daily accumulated exposure to soil moisture and temperature conditions (dose). Dose, a mechanistic weighting of daily exposure conditions over time, generally performed better than exposure time alone as a predictor of in-ground wood decay progression. The open-access availability of remotely sensed soil-state data in combination with wood specimen data proved promising for in-ground wood decay predictions.},
	number = {1},
	urldate = {2024-03-13},
	journal = {European Journal of Remote Sensing},
	author = {Marais, Brendan N. and Schönauer, Marian and van Niekerk, Philip Bester and Niklewski, Jonas and Brischke, Christian},
	month = dec,
	year = {2023},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/22797254.2023.2264473},
	keywords = {dose–response model, Fungal wood decay, geospatial modelling, IRG-WP durability database, soil moisture, soil temperature},
	pages = {2264473},
	file = {Full Text PDF:/home/maicher/Zotero/storage/XWDES8I2/Marais et al. - 2023 - Modelling in-ground wood decay using time-series r.pdf:application/pdf},
}

This article presents models to predict the time until mechanical failure of in-ground wooden test specimens resulting from fungal decay. Historical records of decay ratings were modelled by remotely sensed data from ERA5-Land. In total, 2,570 test specimens of 16 different wood species were exposed at 21 different test sites, representing three continents and climatic conditions from sub-polar to tropical, spanning a period from 1980 until 2022. To obtain specimen decay ratings over their exposure time, inspections were conducted in mostly annual and sometimes bi-annual intervals. For each specimen’s exposure period, a laboratory developed dose–response model was populated using remotely sensed soil moisture and temperature data retrieved from ERA5-Land. Wood specimens were grouped according to natural durability rankings to reduce the variability of in-ground wood decay rate between wood species. Non-linear, sigmoid-shaped models were then constructed to describe wood decay progression as a function of daily accumulated exposure to soil moisture and temperature conditions (dose). Dose, a mechanistic weighting of daily exposure conditions over time, generally performed better than exposure time alone as a predictor of in-ground wood decay progression. The open-access availability of remotely sensed soil-state data in combination with wood specimen data proved promising for in-ground wood decay predictions.

The effect of weathering on the surface moisture conditions of Norway spruce under outdoor exposure. Niklewski, J.; Van Niekerk, P. B.; and Marais, B. N. Wood Material Science & Engineering, 18(4): 1394–1404. July 2023.
Paper   doi   link   bibtex  

@article{niklewski_effect_2023,
	title = {The effect of weathering on the surface moisture conditions of {Norway} spruce under outdoor exposure},
	volume = {18},
	issn = {1748-0272, 1748-0280},
	url = {https://www.tandfonline.com/doi/full/10.1080/17480272.2022.2144444},
	doi = {10.1080/17480272.2022.2144444},
	language = {en},
	number = {4},
	urldate = {2023-12-12},
	journal = {Wood Material Science \& Engineering},
	author = {Niklewski, Jonas and Van Niekerk, Philip Bester and Marais, Brendan Nicholas},
	month = jul,
	year = {2023},
	pages = {1394--1404},
	file = {Volltext:/home/maicher/Zotero/storage/74NILAJR/Niklewski et al. - 2023 - The effect of weathering on the surface moisture c.pdf:application/pdf},
}

  2022 (9)

Laminated Veneer Lumber Made From Cement-Impregnated Veneers. Hirschmüller, S.; Kovryga, A.; Unterberger, S.; Larbig, H.; Marais, B.; Brischke, C.; van de Kuilen, J.; and Krey, A. In Proceedings of 10th European Conference on Wood Modification, pages 108–111, Nancy, France, April 2022. University of Lorraine
link   bibtex  

@inproceedings{hirschmuller_laminated_2022,
	address = {Nancy, France},
	title = {Laminated {Veneer} {Lumber} {Made} {From} {Cement}-{Impregnated} {Veneers}},
	isbn = {978-2-37111-000-7},
	language = {EN},
	booktitle = {Proceedings of 10th {European} {Conference} on {Wood} {Modification}},
	publisher = {University of Lorraine},
	author = {Hirschmüller, S. and Kovryga, A. and Unterberger, S. and Larbig, H. and Marais, B. and Brischke, C. and van de Kuilen, J.-W. and Krey, A.},
	month = apr,
	year = {2022},
	pages = {108--111},
}

Wood durability in terrestrial and aquatic environments – A review of biotic and abiotic influence factors. Marais, B. N.; Brischke, C.; and Militz, H. Wood Material Science & Engineering, 17(2): 82–105. 2022. Publisher: Taylor & Francis _eprint: https://doi.org/10.1080/17480272.2020.1779810
Paper   doi   link   bibtex   abstract  

@article{marais_wood_2022,
	title = {Wood durability in terrestrial and aquatic environments – {A} review of biotic and abiotic influence factors},
	volume = {17},
	issn = {1748-0272},
	url = {https://doi.org/10.1080/17480272.2020.1779810},
	doi = {10.1080/17480272.2020.1779810},
	abstract = {Factors relevant to degradation are important in every wood application. For wood used in ground and water contact; well documented abiotic factors (or agents) include exposure to temperature and moisture linked to the physiological requirements of biotic degradation agents such as wood-decaying fungi and bacteria. Other biotic degradation agents such as subterranean insects and marine borers occur overshadowing the effect of fungal and bacterial decay, but are restricted in geographical distribution and to aquatic applications, respectively. This review focusses on decay specific to soil exposure. The inherent material characteristics are important to durability in that heartwood and sapwood show differences in resistance to degradation between species, provenance, and individual trees. Wood durability testing methods and classification, as well as a summary of prominent models and variables suitable for regional-level modelling of in-ground wood durability are presented.},
	number = {2},
	urldate = {2022-03-17},
	journal = {Wood Material Science \& Engineering},
	author = {Marais, Brendan Nicholas and Brischke, Christian and Militz, Holger},
	year = {2022},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/17480272.2020.1779810},
	keywords = {fungi, bacteria, soil contact, marine environment, Decay, freshwater contact},
	pages = {82--105},
	file = {Full Text PDF:/home/maicher/Zotero/storage/IL39GT2D/Marais et al. - 2022 - Wood durability in terrestrial and aquatic environ.pdf:application/pdf},
}

Factors relevant to degradation are important in every wood application. For wood used in ground and water contact; well documented abiotic factors (or agents) include exposure to temperature and moisture linked to the physiological requirements of biotic degradation agents such as wood-decaying fungi and bacteria. Other biotic degradation agents such as subterranean insects and marine borers occur overshadowing the effect of fungal and bacterial decay, but are restricted in geographical distribution and to aquatic applications, respectively. This review focusses on decay specific to soil exposure. The inherent material characteristics are important to durability in that heartwood and sapwood show differences in resistance to degradation between species, provenance, and individual trees. Wood durability testing methods and classification, as well as a summary of prominent models and variables suitable for regional-level modelling of in-ground wood durability are presented.

Dauerhaftigkeit im Erdkontakt – Einfluss von Feuchte, Temperatur und biologischer Bodenaktivität. Marais, B. N. In 31. Deutsche Holzschutztagung, Dresden, Germany, 2022.
link   bibtex  

@inproceedings{marais_dauerhaftigkeit_2022,
	address = {Dresden, Germany},
	title = {Dauerhaftigkeit im {Erdkontakt} – {Einfluss} von {Feuchte}, {Temperatur} und biologischer {Bodenaktivität}},
	booktitle = {31. {Deutsche} {Holzschutztagung}},
	author = {Marais, Brendan N.},
	year = {2022},
}

Simulations of microclimates for wood-decaying fungi in the built environment using environmental analysis. Van Niekerk, P.; Niklewski, J.; Hosseini, S. H.; Marais, B. N.; Frimannslund, I.; Kringlebotn Thiis, T; and Brischke, C. In Proceedings IRG Annual Meeting, Bled, Slovenia, May 2022.
doi   link   bibtex  

@inproceedings{van_niekerk_simulations_2022,
	address = {Bled, Slovenia},
	title = {Simulations of microclimates for wood-decaying fungi in the built environment using environmental analysis},
	doi = {IRG/WP 23-20703},
	language = {En},
	booktitle = {Proceedings {IRG} {Annual} {Meeting}},
	author = {Van Niekerk, P.B. and Niklewski, J. and Hosseini, S. H. and Marais, B. N. and Frimannslund, I. and Kringlebotn Thiis, T and Brischke, C.},
	month = may,
	year = {2022},
}

Using satellite-retrieved soil moisture data to model the decay risk of in-ground timber. Van Niekerk, P.; Schönauer, M.; Marais, B. N.; and Brischke, C. In Proceedings IRG Annual Meeting, Bled, Slovenia, May 2022.
doi   link   bibtex  

@inproceedings{van_niekerk_using_2022,
	address = {Bled, Slovenia},
	title = {Using satellite-retrieved soil moisture data to model the decay risk of in-ground timber},
	doi = {IRG/WP 22-20689},
	language = {En},
	booktitle = {Proceedings {IRG} {Annual} {Meeting}},
	author = {Van Niekerk, P.B. and Schönauer, M. and Marais, B. N. and Brischke, C.},
	month = may,
	year = {2022},
}

Studies into the effect of soil type and soil layer on the in-ground decay of European beech. Marais, B. N.; Kovacs, S.; Jansen, M.; and Brischke, C. In Proceedings IRG Annual Meeting, Bled, Slovenia, May 2022.
doi   link   bibtex  

@inproceedings{marais_studies_2022,
	address = {Bled, Slovenia},
	title = {Studies into the effect of soil type and soil layer on the in-ground decay of {European} beech},
	doi = {IRG/WP 22-20681},
	language = {En},
	booktitle = {Proceedings {IRG} {Annual} {Meeting}},
	author = {Marais, B. N. and Kovacs, S. and Jansen, M. and Brischke, C.},
	month = may,
	year = {2022},
}

Mapping the biotic degradation hazard of wood in Europe – biophysical background, engineering applications, and climate change-induced prospects. van Niekerk, P. B.; Marais, B. N.; Brischke, C.; Borges, L. M.; Kutnik, M.; Niklewski, J.; Ansard, D.; Humar, M.; Cragg, S. M.; and Militz, H. Holzforschung, 76(2): 188–210. February 2022.
Paper   doi   link   bibtex   abstract   1 download  

@article{van_niekerk_mapping_2022,
	title = {Mapping the biotic degradation hazard of wood in {Europe} – biophysical background, engineering applications, and climate change-induced prospects},
	volume = {76},
	issn = {0018-3830, 1437-434X},
	url = {https://www.degruyter.com/document/doi/10.1515/hf-2021-0169/html},
	doi = {10.1515/hf-2021-0169},
	abstract = {Abstract
            
              Construction using timber has seen a resurgence in light of global climate mitigation policies. Wood is a renewable resource, and engineered wood products are proving to be competitive against concrete and steel while having several advantages. However, while the renewable nature of wood in construction is a beneficial property for climate mitigation policies, the process of biodegradation introduces a challenge for service life planning. A review of hazard mapping is presented while developing contemporary hazard maps, occurrence maps and projected hazard maps for 2050 using representative concentration pathways (
              RCP
              ) 2.6 and 8.5. The risk of timber decay is expected to increase in most of Europe as the temperatures rise, with a decrease expected in dryer regions. Termites are likely to experience a range expansion as more areas become suitable, while human activity and an increase in extreme weather events like floods are expected to facilitate dispersion. Marine borer species already present a risk in most European coastal regions; however, the effect of changes in water temperatures are likely to shift the boundaries for individual borer species. Overall, warmer climates are expected to increase the metabolic activity of all of these organisms leading to a general reduction in service life.},
	language = {en},
	number = {2},
	urldate = {2022-02-09},
	journal = {Holzforschung},
	author = {van Niekerk, Philip B. and Marais, Brendan N. and Brischke, Christian and Borges, Luisa M.S. and Kutnik, Magdalena and Niklewski, Jonas and Ansard, David and Humar, Miha and Cragg, Simon M. and Militz, Holger},
	month = feb,
	year = {2022},
	keywords = {fungi, termites, decay risk, exposure model, marine borers, service life prediction},
	pages = {188--210},
	file = {van Niekerk et al. - 2021 - Mapping the biotic degradation hazard of wood in E.pdf:/home/maicher/Zotero/storage/SLNQ2G7F/van Niekerk et al. - 2021 - Mapping the biotic degradation hazard of wood in E.pdf:application/pdf},
}

Abstract Construction using timber has seen a resurgence in light of global climate mitigation policies. Wood is a renewable resource, and engineered wood products are proving to be competitive against concrete and steel while having several advantages. However, while the renewable nature of wood in construction is a beneficial property for climate mitigation policies, the process of biodegradation introduces a challenge for service life planning. A review of hazard mapping is presented while developing contemporary hazard maps, occurrence maps and projected hazard maps for 2050 using representative concentration pathways ( RCP ) 2.6 and 8.5. The risk of timber decay is expected to increase in most of Europe as the temperatures rise, with a decrease expected in dryer regions. Termites are likely to experience a range expansion as more areas become suitable, while human activity and an increase in extreme weather events like floods are expected to facilitate dispersion. Marine borer species already present a risk in most European coastal regions; however, the effect of changes in water temperatures are likely to shift the boundaries for individual borer species. Overall, warmer climates are expected to increase the metabolic activity of all of these organisms leading to a general reduction in service life.

The effect of weathering on the surface moisture conditions of Norway spruce under outdoor exposure. Niklewski, J.; Van Niekerk, P. B.; and Marais, B. N. Wood Material Science & Engineering,1–11. December 2022.
Paper   doi   link   bibtex   abstract  

@article{niklewski_effect_2022,
	title = {The effect of weathering on the surface moisture conditions of {Norway} spruce under outdoor exposure},
	issn = {1748-0272, 1748-0280},
	url = {https://www.tandfonline.com/doi/full/10.1080/17480272.2022.2144444},
	doi = {10.1080/17480272.2022.2144444},
	abstract = {Life-Cycle-Costing (LCC) is one of the basic indicators for the assessment of sustainability and cost effectiveness in construction applications. Project WoodLCC was thus conceived to enable LCC through input from models for detailed service life planning of wooden components and buildings. The project is a continuation of the service life planning research conducted in Europe over the last three decades, specifically applicable to wooden constructions. The novelty of WoodLCC lies in the optimisation of input data required for LCC of wood-based building components. Instead of generic data, the service life of wooden building components will be assessed with novel methods including performance models that account for fungal and weathering ‘damage’, which take climate, design, and use conditions into consideration. Service life estimates will be linked to consumer acceptance thresholds of planners, house builders and owners.},
	language = {en},
	urldate = {2023-06-15},
	journal = {Wood Material Science \& Engineering},
	author = {Niklewski, Jonas and Van Niekerk, Philip Bester and Marais, Brendan Nicholas},
	month = dec,
	year = {2022},
	pages = {1--11},
	file = {Niklewski et al. - 2022 - The effect of weathering on the surface moisture c.pdf:/home/maicher/Zotero/storage/3PJ8QVQD/Niklewski et al. - 2022 - The effect of weathering on the surface moisture c.pdf:application/pdf},
}

Life-Cycle-Costing (LCC) is one of the basic indicators for the assessment of sustainability and cost effectiveness in construction applications. Project WoodLCC was thus conceived to enable LCC through input from models for detailed service life planning of wooden components and buildings. The project is a continuation of the service life planning research conducted in Europe over the last three decades, specifically applicable to wooden constructions. The novelty of WoodLCC lies in the optimisation of input data required for LCC of wood-based building components. Instead of generic data, the service life of wooden building components will be assessed with novel methods including performance models that account for fungal and weathering ‘damage’, which take climate, design, and use conditions into consideration. Service life estimates will be linked to consumer acceptance thresholds of planners, house builders and owners.

The effect of weathering on the surface moisture conditions of Norway spruce under outdoor exposure. Niklewski, J.; van Niekerk, P. B.; and Marais, B. N. Wood Material Science & Engineering, 0(0): 1–11. December 2022. Publisher: Taylor & Francis _eprint: https://doi.org/10.1080/17480272.2022.2144444
Paper   doi   link   bibtex   abstract  

@article{niklewski_effect_2022-1,
	title = {The effect of weathering on the surface moisture conditions of {Norway} spruce under outdoor exposure},
	volume = {0},
	issn = {1748-0272},
	url = {https://doi.org/10.1080/17480272.2022.2144444},
	doi = {10.1080/17480272.2022.2144444},
	abstract = {Understanding wood surface moisture variations is fundamental to the modelling of moisture content. Exposure to sunlight, fluctuating temperature and rain leads to superficial deterioration and reduced surface hydrophobicity. Here, the effect of weathering was studied through monitoring the surface and global moisture content of axially matched pre-weathered and planed sets of specimens exposed outdoors over 18 months. The difference in surface conditions was characterised by analysing the rain-induced peaks. The results suggest that, following precipitation, weathered surfaces remain wet over a longer time period. No effect was observed through the global moisture content. After one year of exposure, the difference between pre-weathered and planed surfaces was small to insignificant. In service life modelling, it is therefore unnecessary to consider the unweathered state and simulations should target the behaviour of weathered wood. Numerical simulations were able to capture the general behaviour of the surface and global moisture content, but discrepancies over individual peaks were observed. Finally, the study demonstrates how peak analysis and signal analysis can be used for isolating subtle differences between time-series of surface moisture content. The same techniques can be used in future studies to characterise other factors influencing surface conditions, such as wood species and detailing.},
	number = {0},
	urldate = {2022-12-14},
	journal = {Wood Material Science \& Engineering},
	author = {Niklewski, Jonas and van Niekerk, Philip Bester and Marais, Brendan Nicholas},
	month = dec,
	year = {2022},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/17480272.2022.2144444},
	keywords = {moisture content, weathering, measurements, surface conditions, Wood},
	pages = {1--11},
	file = {Full Text PDF:/home/maicher/Zotero/storage/HYF4Q2FB/Niklewski et al. - 2022 - The effect of weathering on the surface moisture c.pdf:application/pdf},
}

Understanding wood surface moisture variations is fundamental to the modelling of moisture content. Exposure to sunlight, fluctuating temperature and rain leads to superficial deterioration and reduced surface hydrophobicity. Here, the effect of weathering was studied through monitoring the surface and global moisture content of axially matched pre-weathered and planed sets of specimens exposed outdoors over 18 months. The difference in surface conditions was characterised by analysing the rain-induced peaks. The results suggest that, following precipitation, weathered surfaces remain wet over a longer time period. No effect was observed through the global moisture content. After one year of exposure, the difference between pre-weathered and planed surfaces was small to insignificant. In service life modelling, it is therefore unnecessary to consider the unweathered state and simulations should target the behaviour of weathered wood. Numerical simulations were able to capture the general behaviour of the surface and global moisture content, but discrepancies over individual peaks were observed. Finally, the study demonstrates how peak analysis and signal analysis can be used for isolating subtle differences between time-series of surface moisture content. The same techniques can be used in future studies to characterise other factors influencing surface conditions, such as wood species and detailing.

  2021 (4)

Mapping the Present and Future Fungal Decay Hazard of Aboveground Wood in Europe. Marais, B. N.; Van Niekerk, P. B.; Niklewski, J.; Brischke, C.; and Militz, H. In Proceedings of the 17th annual meeting of the Northern European Network for Wood Science and Engineering (WSE 2021), pages 60–62, Kaunas, Lithuania, October 2021.
link   bibtex  

@inproceedings{marais_mapping_2021,
	address = {Kaunas, Lithuania},
	title = {Mapping the {Present} and {Future} {Fungal} {Decay} {Hazard} of {Aboveground} {Wood} in {Europe}},
	isbn = {978-609-02-1762-7},
	language = {EN},
	booktitle = {Proceedings of the 17th annual meeting of the {Northern} {European} {Network} for {Wood} {Science} and {Engineering} ({WSE} 2021)},
	author = {Marais, Brendan Nicholas and Van Niekerk, Philip Bester and Niklewski, Jonas and Brischke, Christian and Militz, Holger},
	month = oct,
	year = {2021},
	pages = {60--62},
}

Studies into Fungal Decay of Wood in Ground Contact—Part 2: Development of a Dose–Response Model to Predict Decay Rate. Marais, B. N.; van Niekerk, P. B.; and Brischke, C. Forests, 12(6): 698. May 2021.
Paper   doi   link   bibtex   abstract   2 downloads  

@article{marais_studies_2021,
	title = {Studies into {Fungal} {Decay} of {Wood} in {Ground} {Contact}—{Part} 2: {Development} of a {Dose}–{Response} {Model} to {Predict} {Decay} {Rate}},
	volume = {12},
	issn = {1999-4907},
	shorttitle = {Studies into {Fungal} {Decay} of {Wood} in {Ground} {Contact}—{Part} 2},
	url = {https://www.mdpi.com/1999-4907/12/6/698},
	doi = {10.3390/f12060698},
	abstract = {In this article a dose–response model was developed to describe the effect of soil temperature, soil moisture content, and soil water-holding capacity, on the decay of European beech (Fagus sylvatica) wood specimens exposed to soil contact. The developed dose–response model represents a step forward in incorporating soil-level variables into the prediction of wood decay over time. This builds upon prior models such as those developed within the TimberLife software package, but also aligns with similar modeling methodology employed for wood exposed above ground. The model was developed from laboratory data generated from terrestrial microcosm trials which used test specimens of standard dimension, incubated in a range of soil conditions and temperatures, for a maximum period of 16 weeks. Wood mass loss was used as a metric for wood decay. The dose aspect of the developed function modelled wood mass loss in two facets; soil temperature against wood mass loss, and soil water-holding capacity and soil moisture content against wood mass loss. In combination, the two functions describe the wood mass loss as a function of a total daily exposure dose, accumulated over the exposure period. The model was deemed conservative, delivering an overprediction of wood decay, or underprediction of wood service-life, when validated on a similar, but independent dataset (R2 = 0.65). Future works will develop similar models for outdoor, fieldtrial datasets as a basis for service-life prediction of wooden elements used in soil contact.},
	language = {en},
	number = {6},
	urldate = {2021-06-01},
	journal = {Forests},
	author = {Marais, Brendan Nicholas and van Niekerk, Philip Bester and Brischke, Christian},
	month = may,
	year = {2021},
	pages = {698},
	file = {Marais et al. - 2021 - Studies into Fungal Decay of Wood in Ground Contac.pdf:/home/maicher/Zotero/storage/TB9KJ2AS/Marais et al. - 2021 - Studies into Fungal Decay of Wood in Ground Contac.pdf:application/pdf},
}

In this article a dose–response model was developed to describe the effect of soil temperature, soil moisture content, and soil water-holding capacity, on the decay of European beech (Fagus sylvatica) wood specimens exposed to soil contact. The developed dose–response model represents a step forward in incorporating soil-level variables into the prediction of wood decay over time. This builds upon prior models such as those developed within the TimberLife software package, but also aligns with similar modeling methodology employed for wood exposed above ground. The model was developed from laboratory data generated from terrestrial microcosm trials which used test specimens of standard dimension, incubated in a range of soil conditions and temperatures, for a maximum period of 16 weeks. Wood mass loss was used as a metric for wood decay. The dose aspect of the developed function modelled wood mass loss in two facets; soil temperature against wood mass loss, and soil water-holding capacity and soil moisture content against wood mass loss. In combination, the two functions describe the wood mass loss as a function of a total daily exposure dose, accumulated over the exposure period. The model was deemed conservative, delivering an overprediction of wood decay, or underprediction of wood service-life, when validated on a similar, but independent dataset (R2 = 0.65). Future works will develop similar models for outdoor, fieldtrial datasets as a basis for service-life prediction of wooden elements used in soil contact.

Modelling the Material Resistance of Wood—Part 1: Utilizing Durability Test Data Based on Different Reference Wood Species. Alfredsen, G.; Brischke, C.; Marais, B. N.; Stein, R. F. A.; Zimmer, K.; and Humar, M. Forests, 12(5): 558. April 2021.
Paper   doi   link   bibtex   abstract   2 downloads  

@article{alfredsen_modelling_2021,
	title = {Modelling the {Material} {Resistance} of {Wood}—{Part} 1: {Utilizing} {Durability} {Test} {Data} {Based} on {Different} {Reference} {Wood} {Species}},
	volume = {12},
	issn = {1999-4907},
	shorttitle = {Modelling the {Material} {Resistance} of {Wood}—{Part} 1},
	url = {https://www.mdpi.com/1999-4907/12/5/558},
	doi = {10.3390/f12050558},
	abstract = {To evaluate the performance of new wood-based products, reference wood species with known performances are included in laboratory and field trials. However, different wood species vary in their durability performance, and there will also be a within-species variation. The primary aim of this paper was to compare the material resistance against decay fungi and moisture performance of three European reference wood species, i.e., Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica). Wood material was collected from 43 locations all over Europe and exposed to brown rot (Rhodonia placenta), white rot (Trametes versicolor) or soft rot fungi. In addition, five different moisture performance characteristics were analyzed. The main results were the two factors accounting for the wetting ability (kwa) and the inherent protective properties of wood (kinh), factors for conversion between Norway spruce vs. Scots pine sapwood or European beech for the three decay types and four moisture tests, and material resistance dose (DRd) per wood species. The data illustrate that the differences between the three European reference wood species were minor, both with regard to decay and moisture performance. The results also highlight the importance of defined boundaries for density and annual ring width when comparing materials within and between experiments. It was concluded that with the factors obtained, existing, and future test data, where only one or two of the mentioned reference species were used, can be transferred to models and prediction tools that use another of the reference species.},
	language = {en},
	number = {5},
	urldate = {2021-05-18},
	journal = {Forests},
	author = {Alfredsen, Gry and Brischke, Christian and Marais, Brendan N. and Stein, Robert F. A. and Zimmer, Katrin and Humar, Miha},
	month = apr,
	year = {2021},
	pages = {558},
	file = {Alfredsen et al. - 2021 - Modelling the Material Resistance of Wood—Part 1 .pdf:/home/maicher/Zotero/storage/MATGEGAE/Alfredsen et al. - 2021 - Modelling the Material Resistance of Wood—Part 1 .pdf:application/pdf},
}

To evaluate the performance of new wood-based products, reference wood species with known performances are included in laboratory and field trials. However, different wood species vary in their durability performance, and there will also be a within-species variation. The primary aim of this paper was to compare the material resistance against decay fungi and moisture performance of three European reference wood species, i.e., Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica). Wood material was collected from 43 locations all over Europe and exposed to brown rot (Rhodonia placenta), white rot (Trametes versicolor) or soft rot fungi. In addition, five different moisture performance characteristics were analyzed. The main results were the two factors accounting for the wetting ability (kwa) and the inherent protective properties of wood (kinh), factors for conversion between Norway spruce vs. Scots pine sapwood or European beech for the three decay types and four moisture tests, and material resistance dose (DRd) per wood species. The data illustrate that the differences between the three European reference wood species were minor, both with regard to decay and moisture performance. The results also highlight the importance of defined boundaries for density and annual ring width when comparing materials within and between experiments. It was concluded that with the factors obtained, existing, and future test data, where only one or two of the mentioned reference species were used, can be transferred to models and prediction tools that use another of the reference species.

Weathering Stability and Durability of Birch Plywood Modified with Different Molecular Weight Phenol-Formaldehyde Oligomers. Grinins, J.; Biziks, V.; Marais, B. N.; Rizikovs, J.; and Militz, H. Polymers, 13(2): 175. January 2021.
Paper   doi   link   bibtex   abstract  

@article{grinins_weathering_2021,
	title = {Weathering {Stability} and {Durability} of {Birch} {Plywood} {Modified} with {Different} {Molecular} {Weight} {Phenol}-{Formaldehyde} {Oligomers}},
	volume = {13},
	issn = {2073-4360},
	url = {https://www.mdpi.com/2073-4360/13/2/175},
	doi = {10.3390/polym13020175},
	abstract = {This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the weathering stability and biological durability of birch plywood. Silver birch (Betula pendula) veneers were vacuum-pressure impregnated with four different PF resins with average molecular weights (Mw) of 292 (resin A), 528 (resin B), 703 (resin C), and 884 g/mol (resin D). The aging properties of PF resin modified birch plywood were analyzed using artificial weathering with ultraviolet (UV) light, UV and water spray, and weathering under outdoor conditions. The same combinations of PF-treated plywood specimens were then tested in soil-bed tests to determine their resistance against soft-rot wood decay. It was not possible to compare weathering processes under artificial conditions to processes under outdoor conditions. However, the weathering stability of birch plywood treated with PF resins A, B, and C, scored better than plywood treated with commercial resin D (regardless of solid content concentration [\%]). Results from unsterile soil bed tests showed improvements in resistance to soft-rot wood decay compared to untreated plywood and solid wood. Mass loss [\%] was lowest for birch plywood specimens treated with resin of highest solid content concentration (resin D, 20\%). Provisional durability ratings delivered durability class (DC) ratings of 2–3, considerably improved over untreated solid wood and untreated birch plywood (DC 5).},
	language = {en},
	number = {2},
	urldate = {2021-01-14},
	journal = {Polymers},
	author = {Grinins, Juris and Biziks, Vladimirs and Marais, Brendan Nicholas and Rizikovs, Janis and Militz, Holger},
	month = jan,
	year = {2021},
	pages = {175},
	file = {Grinins et al. - 2021 - Weathering Stability and Durability of Birch Plywo.pdf:/home/maicher/Zotero/storage/TVDB5KNC/Grinins et al. - 2021 - Weathering Stability and Durability of Birch Plywo.pdf:application/pdf},
}

This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the weathering stability and biological durability of birch plywood. Silver birch (Betula pendula) veneers were vacuum-pressure impregnated with four different PF resins with average molecular weights (Mw) of 292 (resin A), 528 (resin B), 703 (resin C), and 884 g/mol (resin D). The aging properties of PF resin modified birch plywood were analyzed using artificial weathering with ultraviolet (UV) light, UV and water spray, and weathering under outdoor conditions. The same combinations of PF-treated plywood specimens were then tested in soil-bed tests to determine their resistance against soft-rot wood decay. It was not possible to compare weathering processes under artificial conditions to processes under outdoor conditions. However, the weathering stability of birch plywood treated with PF resins A, B, and C, scored better than plywood treated with commercial resin D (regardless of solid content concentration [%]). Results from unsterile soil bed tests showed improvements in resistance to soft-rot wood decay compared to untreated plywood and solid wood. Mass loss [%] was lowest for birch plywood specimens treated with resin of highest solid content concentration (resin D, 20%). Provisional durability ratings delivered durability class (DC) ratings of 2–3, considerably improved over untreated solid wood and untreated birch plywood (DC 5).

  2020 (2)

Studies into Fungal Decay of Wood In Ground Contact—Part 1: The Influence of Water-Holding Capacity, Moisture Content, and Temperature of Soil Substrates on Fungal Decay of Selected Timbers. Marais, B. N.; Brischke, C.; Militz, H.; Peters, J. H.; and Reinhardt, L. Forests, 11(12): 1284. November 2020.
Paper   doi   link   bibtex   abstract   4 downloads  

@article{marais_studies_2020,
	title = {Studies into {Fungal} {Decay} of {Wood} {In} {Ground} {Contact}—{Part} 1: {The} {Influence} of {Water}-{Holding} {Capacity}, {Moisture} {Content}, and {Temperature} of {Soil} {Substrates} on {Fungal} {Decay} of {Selected} {Timbers}},
	volume = {11},
	issn = {1999-4907},
	shorttitle = {Studies into {Fungal} {Decay} of {Wood} {In} {Ground} {Contact}—{Part} 1},
	url = {https://www.mdpi.com/1999-4907/11/12/1284},
	doi = {10.3390/f11121284},
	abstract = {This article presents the results from two separate studies investigating the decay of wood in ground contact using adapted versions of laboratory-based terrestrial microcosm (TMC) tests according to CEN/TS 15083-2:2005. The first study (A) sought to isolate the effect of soil water-holding capacity (WHCsoil [\%]) and soil moisture content (MCsoil [\%WHCsoil]) on the decay of five commercially important wood species; European beech (Fagus sylvatica), English oak heartwood (Quercus robur), Norway spruce (Picea abies), Douglas-fir heartwood (Pseudotsuga menziesii), and Scots pine sapwood (Pinus sylvestris), while keeping soil temperature (Tsoil) constant. Combinations of soil mixtures with WHCsoil of 30\%, 60\%, and 90\%, and MCsoil of 30\%, 70\%, and 95\%WHCsoil were utilized. A general trend showed higher wood decay, measured in oven-dry mass loss (MLwood [\%]), for specimens of all species incubated in soils with WHCsoil of 60\% and 90\% compared to 30\%. Furthermore, drier soils (MCsoil of 30 and 70\%WHCsoil) showed higher MLwood compared to wetter soils (95\%WHCsoil). The second study (B) built on the first’s findings, and sought to isolate the effect of Tsoil and MCsoil on the decay of European beech wood, while keeping WHCsoil constant. The study used constant incubation temperature intervals (Tsoil), 5–40 ◦C, and alternating intervals of 10/20, 10/30, and 20/30 ◦C. A general trend showed drier MCsoil (60\%WHCsoil), and Tsoil of 20–40 ◦C, delivered high wood decay (MLwood {\textgreater} 20\%). Higher MCsoil (90\%WHCsoil) and Tsoil of 5–10 ◦C, delivered low wood decay (MLwood {\textless} 5\%). Alternating Tsoil generally delivered less MLwood compared to their mean constant Tsoil counterparts (15, 20, 25 ◦C). The results suggest that differences in wood species and inoculum potential (WHCsoil) between sites, as well as changes in MCsoil and Tsoil attributed to daily and seasonal weather patterns can influence in-ground wood decay rate.},
	language = {en},
	number = {12},
	urldate = {2020-12-03},
	journal = {Forests},
	author = {Marais, Brendan Nicholas and Brischke, Christian and Militz, Holger and Peters, Johann Hinrich and Reinhardt, Lena},
	month = nov,
	year = {2020},
	pages = {1284},
	file = {Marais et al. - 2020 - Studies into Fungal Decay of Wood In Ground Contac.pdf:/home/maicher/Zotero/storage/NZ3RZLBZ/Marais et al. - 2020 - Studies into Fungal Decay of Wood In Ground Contac.pdf:application/pdf},
}

This article presents the results from two separate studies investigating the decay of wood in ground contact using adapted versions of laboratory-based terrestrial microcosm (TMC) tests according to CEN/TS 15083-2:2005. The first study (A) sought to isolate the effect of soil water-holding capacity (WHCsoil [%]) and soil moisture content (MCsoil [%WHCsoil]) on the decay of five commercially important wood species; European beech (Fagus sylvatica), English oak heartwood (Quercus robur), Norway spruce (Picea abies), Douglas-fir heartwood (Pseudotsuga menziesii), and Scots pine sapwood (Pinus sylvestris), while keeping soil temperature (Tsoil) constant. Combinations of soil mixtures with WHCsoil of 30%, 60%, and 90%, and MCsoil of 30%, 70%, and 95%WHCsoil were utilized. A general trend showed higher wood decay, measured in oven-dry mass loss (MLwood [%]), for specimens of all species incubated in soils with WHCsoil of 60% and 90% compared to 30%. Furthermore, drier soils (MCsoil of 30 and 70%WHCsoil) showed higher MLwood compared to wetter soils (95%WHCsoil). The second study (B) built on the first’s findings, and sought to isolate the effect of Tsoil and MCsoil on the decay of European beech wood, while keeping WHCsoil constant. The study used constant incubation temperature intervals (Tsoil), 5–40 ◦C, and alternating intervals of 10/20, 10/30, and 20/30 ◦C. A general trend showed drier MCsoil (60%WHCsoil), and Tsoil of 20–40 ◦C, delivered high wood decay (MLwood \textgreater 20%). Higher MCsoil (90%WHCsoil) and Tsoil of 5–10 ◦C, delivered low wood decay (MLwood \textless 5%). Alternating Tsoil generally delivered less MLwood compared to their mean constant Tsoil counterparts (15, 20, 25 ◦C). The results suggest that differences in wood species and inoculum potential (WHCsoil) between sites, as well as changes in MCsoil and Tsoil attributed to daily and seasonal weather patterns can influence in-ground wood decay rate.

Wood protection with cement – Part 1: Coating matters and durability of cement coated wood. Hirschmüller, S.; Marais, B.; Brischke, C.; Krey, A.; and Bösing, J. In Proceedings IRG Annual Meeting, pages 25, online, webinar, June 2020.
doi   link   bibtex   abstract   1 download  

@inproceedings{hirschmuller_wood_2020,
	address = {online, webinar},
	title = {Wood protection with cement – {Part} 1: {Coating} matters and durability of cement coated wood},
	doi = {IRG/WP 20-40911},
	abstract = {The use of wood in geotechnical applications has seen renewed interest. However, concerns related to the durability and service life of wood in ground contact applications remain. Wood has the potential to substitute commonly used steel and concrete in the geotechnical engineering sector, but solutions to extending the service life and maintenance intervals require long-lasting wood protection systems capable of inhibiting fungal and bacterial decay. Cement, one of the constituents of concrete was identified as a potential coating material for wood used in soil stabilisation works. Spruce and beech wood rest rolls from commercial veneer peeling has been identified as a potential source for cement-coated geotechnical wood products. Norway spruce and European beech wood was subsequently used in this study.},
	language = {en},
	booktitle = {Proceedings {IRG} {Annual} {Meeting}},
	author = {Hirschmüller, Sebastian and Marais, Brendan and Brischke, Christian and Krey, Adrian and Bösing, Janine},
	month = jun,
	year = {2020},
	pages = {25},
	file = {Hirschmüller et al. - Wood protection with cement – Part 1 Coating matt.pdf:/home/maicher/Zotero/storage/Z22GT947/Hirschmüller et al. - Wood protection with cement – Part 1 Coating matt.pdf:application/pdf},
}

The use of wood in geotechnical applications has seen renewed interest. However, concerns related to the durability and service life of wood in ground contact applications remain. Wood has the potential to substitute commonly used steel and concrete in the geotechnical engineering sector, but solutions to extending the service life and maintenance intervals require long-lasting wood protection systems capable of inhibiting fungal and bacterial decay. Cement, one of the constituents of concrete was identified as a potential coating material for wood used in soil stabilisation works. Spruce and beech wood rest rolls from commercial veneer peeling has been identified as a potential source for cement-coated geotechnical wood products. Norway spruce and European beech wood was subsequently used in this study.

  2019 (1)

Studies on the durability of European Beech wood in ground contact: understanding the effect of biotic and abiotic factors. Marais, B.; Brischke, C.; and Peters, J. In Proceedings of the 15th Annual Meeting of the Northern European Network on Wood Science and Engineering (WSE), pages 95–97, Lund, Sweden, October 2019.
link   bibtex  

@inproceedings{marais_studies_2019,
	address = {Lund, Sweden},
	title = {Studies on the durability of {European} {Beech} wood in ground contact: understanding the effect of biotic and abiotic factors},
	booktitle = {Proceedings of the 15th {Annual} {Meeting} of the {Northern} {European} {Network} on {Wood} {Science} and {Engineering} ({WSE})},
	author = {Marais, B. and Brischke, C. and Peters, J.},
	month = oct,
	year = {2019},
	pages = {95--97},
}