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  • Principal Investigator Oak Declines
  • Leader – multidisciplinary teams carrying out Oak Decline research

Current Tree Health programme: Evaluation of likelihood of Agrilus biguttatus transmission and vectoring of AOD bacteria and development of rapid diagnostics

Project : Currently leads the Bacteria: Advancement of Control and Knowledge to Save Threatened Oak and Protect them for Future Generations (Bac-Stop) team within the UK Strategic Priorities Fund Bacterial Plant Diseases Programme

Responsible for:

  • Planning and leading integrated research projects
  • Communicating and advising government and industry on oak research matters
  • Managing multidisciplinary teams situated at various national and international venues
  • Identifying knowledge gaps, developing research strategies and shaping research direction
  • Obtaining external funding for research on AOD in the UK (>£M)
  • Sourcing required skills
  • Carrying out research
  • Collating, reporting and publishing findings
  • Transferring information to the sector, interested parties, local authorities, tree groups and charities in the UK

Current research foci

  • Pathology of AOD and COD
  • Identification and mechanisms of predisposition factors and disease development
  • Taxonomy of organisms associated with AOD including entomological, bacteriological and mycological studies
  • Developing rapid diagnostics
  • Metabolomics
  • Dendrochronology – historical predisposition factors
  • Entomology
  • Epidemiology including infection pathways, analyses of spatial aspects
  • Mapping (ClimEx mapping included) and monitoring selected sites
  • Managing reports on the distribution of AOD in the UK
  • Management research
  • Providing management advice.

Sandra obtained a PhD in Plant Pathology from the University of Stellenbosch, South Africa. She has extensive experience in soilborne and stem canker diseases. Her main interests are causes, effects and management of oak declines, where she uses a holistic research approach. Her specific interests are on the pathology and microbiological interactions in acute oak decline and chronic oak decline.

  • Acute Oak Decline (AOD)
  • Chronic Oak Decline (COD)



  • British Society for Plant Pathology
  • South African Society for Plant Pathology

Current international research collaboration:

  • CBS (Netherlands)
  • Forest and Agricultural Biotechnology Institute (FABI, South Africa)
  • Ghent University (Belgium)
  • UPM-INIA, Madrid (Spain)
  • University of Pretoria (South Africa)
  • USDA Forest Services (USA)

Current national research collaboration:

  • Aberystwyth University
  • Bangor University
  • East Malling Research Institute
  • Fera
  • Harper Adams University
  • Imperial College, London
  • Rothamsted Research Institute
  • Swansea University
  • University of Essex
  • University of the West of England



  • Initiator of research on Acute Oak Decline (AOD) and raising awareness of oak health in the UK
  • Numerous publications written and a few book chapters published
  • Secure government, industry, stakeholder funding partnerships
  • Obtain significant external funding for Oak Decline research
  • Establish wide ranging collaborative research networks and partnerships with universities, research organisations, practitioners and stakeholders
  • Extensive knowledge transfer on forest and tree health and pathology
  • Advisor to Parliamentary Enquiries (tree pathology) and the Science Select Committee on forest research and invited Advisor on Acute Oak Decline to HRH the Prince of Wales
  • Supervision of numerous post graduate studentships and post-doctoral research projects
Sandra Denman

Sandra Denman

BSc, HDE, MSc, PhD
Principal Pathologist
Tree health

Alice Holt

Alice Holt Lodge




Related Publications


Solving how a complex disease threatens our iconic oak

Scientists have for the first time tracked down the cause of the stem bleeding symptoms of acute oak decline.


Peer reviewed journal articles

Publications in peer reviewed scientific journals (2012 to present)


Brady C., Orsi, M., Doonan, J.M., Denman, S., Arnold, D. (2021). Brenneria goodwinii growth in vitro is improved by competitive interactions with other bacterial species associated with Acute Oak Decline Microbial Sciences

Finch, J.P., Brown, N., Beckmann, M., Denman, S., Draper, J.  (2021) Index measures for oak decline severity using phenotypic descriptors. Forest Ecology and Management 484, p.118948

Gathercole, L., Nocchi, G., Brown, N., Coker, T., Plumb, W., Stocks, J., Nichols, R., Denman, S., Buggs, R. (2021) Evidence for the widespread occurrence of bacteria implicated in acute oak decline from incidental genetic sampling. Forests 12, 1683.

Nocchi, G., Brown, N., Coker, T.L.R., Plumb, W.J., Stocks, J.J., Denman, S. Buggs, R.J.A. (2021). Genomic structure and diversity of oak populations in British parklands Plants, People Planet pp 1-15

Reed, K., Brown, N., Vanguelova, E., Finch, J., Denman, S. (2021) Current Understanding of Acute Oak Decline: a summary of recent research with implications for woodland management. Quarterly Journal of Forestry and Management 115(1), 38-45.



Bueno-Gonzalez V., Brady, C., Allainguillaume, J., Denman, S., Arnold, D. (2020). A rapid multiplex high resolution melting technique to diagnose pathogenic bacteria associated with acute oak decline from field samples. Manuscript in preparation.

Bueno-Gonzalez V., Brady, C., Denman, S., Allainguillaume, J., Arnold, D. (2020) Pseudomonas kirkiae sp. nov., a novel species isolated from oak in the United Kingdom, and phylogenetic considerations of the genera Pseudomonas, Azotobacter and Azomonas. Int J Syst Evol Microbiol DOI 10.1099/ijsem.0.004055

Crampton, B.G., Plummer, S., Kaczmarek, M., McDonald, J.E. and Denman, S.  (2020) A multiplex real-time PCR assay enables simultaneous rapid detection and quantification of bacteria associated with Acute Oak Decline.  Plant Pathology, available online

Doonan, J.M., Broberg, M., Denman, S., McDonald, J.E. (2020) Host-microbiota-insect interactions drive emergent virulence in a complex tree disease. Proc. R. Soc. B 287: 20200956.

Pettifor, B.J., Doonan, J., Denman, S., McDonald, J.E. (2020) Survival of Brenneria goodwinii and Gibbsiella quercinecans, associated with acute oak decline, in rainwater and forest soil. Syst. Appl. Microbiol. 43(2), 126052.

Pinho, D., Barrozo, C., Froufe, H., Brown, N., Vanguelova, E., Egas, C., Denman, S. (2020). Linking tree health, rhizosphere physicochemical properties, and microbiome in Acute Oak Decline. Forests 11(11) 1153.

Reed, K., Forster, J., Denman, S., Brown, N., Leather, S.R., Inward, D.J.G. (2020) Novel dendrochronological modelling demonstrates that decades of reduced stem growth predispose trees to Acute Oak Decline. Forest Ecology and Management

Scarlett, K., Denman, S., Clark, D.R., Forster, J., Vanguelova, E., Brown, N., Whitby, C. (2020) Relationships between nitrogen cycling microbial community abundance and composition reveal the indirect effect of soil pH on oak decline. The ISME Journal, Multidisciplinary Journal of Microbial Ecology published online 16 October 2020.



Bueno-Gonzalez V., Brady, C., Denman S., Plummer, S., Allainguillaume, J., Arnold, D. (2019). Pseudomonas daroniae sp. nov. and Pseudomonas dryadis sp. nov., isolated from pedunculate oak affected by acute oak decline in the UK. Int. Journal Syst Evol Microbiology. DOI 10.1099/ijsem.0.003615. 69(11).

Denman, S., Doonan, J., Brown, N., Broberg, M., Vanguelova, E., McDonald, J.E. (2019) A holistic approach to investigating acute oak decline. International Oaks 30, 333-340.

Doonan, J., Denman, S., Pachebat, J.A.,  McDonald, J.E. (2019) Genomic analysis of bacteria in the Acute Oak Decline Pathobiome. Microbial Genomics 5, 1-15.

Fraser, S., Gomez-Gallego, Gardner, J., Bulman, L.S., Denman, S., Williams, N.M. (2019) Impact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae. Forest Pathology 50(2) DOI:10.1111/efp.12588

Gagen, M., Matthews, N., Denman, S., Bridge, M., Peace, A., Pike, R., Young, G. (2019). The tree ring growth histories of UK native oaks as a tool for investigating Chronic Oak Decline: an example from the Forest of Dean. Dendrochronologia 55, 50-59.

Moradi‐Amirabad, Y., Rahimian, H., Babaeizad, V., Denman, S. (2019) Brenneria spp. and Rahnella Victoriana associated with acute oak decline symptoms on oak and hornbeam in Iran. Forest Pathology 49(4). 2019;00:e12535. https ://

Quine, C.P., Atkinson, N., Denman, S., Desprez-Loustau, M-L., Jackson, R., Kirby, K. (eds) (2019). Action Oak Knowledge review: an assessment of the current evidence on oak health in the UK, identification of evidence gaps and prioritisation of research needs. Action Oak, Haslemere, UK. ISBN 978-1-5272-4193-0



Broberg, M., Doonan, J., Mundt, F., Denman, S., McDonald, J.E. (2018) Integrated multi-omic analysis of host microbiota interactions in Acute Oak Decline. Microbiome 6(21), 15pp. DOI:10.1186/s40168-018-0408-5

Brown, N., Vanguelova, E., Parnell, S., Broadmeadow, S., Denman, S. (2018) Predisposition of forests to biotic disturbance: Predicting the distribution of Acute Oak Decline using environmental factors. Forest Ecology and Management, 407(1), 145-154.

Reed, K., Denman, S., Leather, S.R., Forster, J., Inward, D.J. (2018). The lifecycle of Agrilus biguttatus: the role of temperature in its development and distribution, and implications for Acute Oak Decline. Agricultural and Forest Entomology, 20(3), 334-346.



Denman, S., Doonan, J., Ransom-Jones, E., Broberg, M., Plummer, S., Kirk, S., Scarlett, K., Griffiths, A.R., Kaczmarek, M., Forster, J., Peace, A., Golyshin, P.N., Hassard, F., Brown, N., Kenny, J.G., McDonald, J.E. (2017) Microbiome and infectivity studies reveal complex polyspecies tree disease in Acute Oak Decline. International Society Microbial Ecology Journal 12, 386–399.

Denman, S., Barrett, G., Kirk, S.A., McDonald, J.E., Coetzee, M.P.A. (2017) Identification of Armillaria species on oak in Britain: Implications for Oak Health. Forestry 90(1), 148-161.

Brady, C., Arnold, D., McDonald, J., Denman, S. (2017) Taxonomy and identification of bacteria associated with Acute Oak Decline. World Journal of Microbiology and Biotechnology 33(143), Springer submitted online 16 June 2017, DOI:10.1007/s11274-017-2296-4.

Brown, N., van den Bosch, F., Parnell, S. and Denman, S. (2017) Integrating regulatory surveys and public reports to map outbreaks of forest diseases: Acute Oak Decline in England and Wales. Royal Society Proceedings B 284: 20170547

Brown, N., Jeger, M., Kirk, S., Williams, D., Xu, X., Pautasso, M.,Denman, S. (2017) Acute Oak Decline and Agrilus biguttatus: The Co-Occurrence of Stem Bleeding and D-Shaped Emergence Holes in Great Britain. Forests 8(3), 87. DOI:10.3390/f8030087.

Kaczmarek, M., Mullett, M.S., McDonald, J.E., Denman, S. (2017) Multilocus sequence typing provides insights into the population structure and evolutionary potential of Brenneria goodwinii, associated with acute oak decline



Denman, S., Plummer, S., Kirk, S.A., Peace, A., McDonald, J.E. (2016) Isolation studies reveal a shift in the microbiome of oak affected with Acute Oak Decline. Systematic and Applied Microbiology 39 (7), 484-490.

Brady, C., Allainguillaume, J., Denman, S., Arnold, D. (2016) Rapid identification of bacteria associated with Acute Oak Decline by high resolution melt (HRM) analysis. Letters in Applied Microbiology 63(2), 89-95.

Doonan, J., Denman, S., McDonald, J.E., Golyshin, P.N. (2016) Shotgun metagenomic sequencing analysis of soft-rot Enterobacteriaceae in polymicrobial communities. Methods in Molecular Biology 1539, 85-97.

Sapp, M., Lewis, E., Moss, S., Barrett, B., Kirk, S., Elphinstone, J., Denman, S. (2016) Metabarcoding of bacteria associated with the acute oak decline syndrome in England. Forests 7(5), 95.

Vuts, J., Woodcock, C.M., Sumner, M., Caulfield, J.C., Reed, K., Inward, D.J.G., Leather, S.R., Pickett, J.A., Birkett, M.A., Denman, S. (2016) Responses of the two-spotted oak buprestid, Agrilus biguttatus (Coleoptera: Buprestidae), to host tree volatiles. Pest Management Science 72, 845-851.



Brown, N., Inward, D.J.G., Jeger, M., Denman, S. (2015) A review of Agrilus biguttatus in UK forests and its relationship with acute oak decline. Forestry 88, 53-63.

Brown, N., Jeger, M., Kirk, S., Xu, X., Denman, S. (2015) Spatial and temporal patterns in symptom expression within eight woodlands affected by Acute Oak Decline. Forest Ecology and Management 360, 97-109.

Brady, C., Irisawa, T., Iino, T., Ohkuma, M., Arnold, D.,Denman, S. (2015) Gibbsiella papilionis Kimet al. 2013 is a later heterotypic synonym ofGibbsiella dentisursi Saito et al. 2012. International Journal of Systematic and Evolutionary Microbiology 65(12), 4788-91.

Doonan, J., Denman, S., Gertler, C., Pachebat, J.A., Golyshin, P.N., McDonald, J.E. (2015) The intergenic transcribed spacer region 1 as a molecular marker for identification and discrimination of Enterobacteriaceae associated with acute oak decline. Journal of Applied Microbiology 118(1), 193-201.



Denman, S., Brown, N., Kirk, S., Jeger, M., Webber, J.F. (2014) A description of the symptoms of Acute Oak Decline in Britain and a comparative review on causes of similar disorders on oak in Europe. Forestry 87, 535-551.

Brady, C., Hunter, G., Kirk, S., Arnold, D., Denman, S. (2014) Rahnella victoriana sp. nov., Rahnella bruchi sp. nov., Rahnella woolbedingensis sp. nov., classification of Rahnella genomospecies 2 and 3 as Rahnella variigena sp. nov. and Rahnella inusitata sp. nov., respectively and emended description of the genus Rahnella. Systematic and Applied Microbiology 37, 545-552.

Brady, C., Hunter, G., Kirk, S., Arnold, D., Denman, S. (2014) Description of Brenneria roseae sp. nov. and two subspecies, Brenneria roseae subspecies roseae ssp. nov and Brenneria roseae subspecies americana ssp. nov. isolated from symptomatic oak. Systematic and Applied Microbiology 37, 391-401.

Brady, C., Hunter, G., Kirk, S., Arnold, D., Denman, S. (2014) Gibbsiella greigii sp. nov., a novel species associated with oak decline in the USA. Systematic and Applied Microbiology 37, 417-422.

Brown, N., Kirk, S., Jeger, M., Webber, J.F., Denman, S. (2014) A description of the symptoms of Acute Oak Decline in Britain and a comparative review on causes of similar disorders on oak in Europe. Forestry 87 (4), 535-551.

Scanu, B., Hunter, G.C., Linaldeddu, B.T., Franceschini, A., Maddau, L., Jung, T. and Denman S. (2014). A taxonomic re-evaluation reveals that Phytophthora cinnamomi and P. cinnamomi var. parvispora are separate species. Forest Pathology 44(1), 1–20.



Denman, S., Brady, C., Kirk, S., Cleenwerck, I., Venter, S., Coutinho, T.A., De Vos, P. (2012) Brenneria goodwinii sp. nov., associated with acute oak decline in the UK. Int. Journal Syst Evol Microbiology 62, 2451-2456.

Brady, C., Cleenwerck, I., Denman, S., Venter, S.N., Rodriguez-Palenzuela, P., Coutinho, T.A., De Vos, P. (2012) Proposal to reclassify Brenneria quercina (Hildebrand and Schroth 1967) Hauben et al. 1999 into a new genus, Lonsdalea gen. nov., as Lonsdalea quercina comb. nov., descriptions of Lonsdalea quercina subsq. quercina comb. nov., Lonsdalea quercina subsq. iberica subsq. nov. and Lonsdalea quercina subsp. británica subsp. nov., emendation of the description of the genus Brenneria, reclassification of Dickeya dieffenbachiae as Dickeya dadantii subsq. Dieffenbachiae comb. nov., and emendation of the description of Dickeya dadantii. International Journal of Systematic and Evolutionary Microbiology 62(7), 1592-1602.