Log in

Editor's Picks

The oak tree in Skjomendalen © Gerhard Sørensen-Fuglem and Cecilia Piccirilli Bjerkeset
An oak grows north of the Arctic Circle in Norway
Website Editor | Aug 14, 2023
Unusual symptoms linked to phytoplasma infection in Quercus humboldtiii, Colombia © Eric Boa
Symptoms linked to phytoplasma infection found in Quercus...
Website Editor | Aug 06, 2023
Different names are being used for one species.
Website Editor | Jun 20, 2023

Plant Focus

A small but mature Alabama sandstone oak producing acorns © Patrick Thompson
A Critically Endangered dwarf oak 

A Holistic Approach to Investigating Acute Oak Decline

PDF icon Log in or register to access the full text.

Sandra Denman, James Doonan, Nathan Brown, Martin Broberg, Elena Vanguelova, and James McDonald

Published May 2019 in International Oaks No. 30: 333–340


Acute oak decline (AOD), presents a serious threat to native British oak. Decline-diseases are complex syndromes, caused by multiple factors operating over time, beginning with environmental predisposition disturbances leading to host stress, followed by invasion of biotic agents (insect pests and pathogens). Determining the role of secondary pests and pathogens presents challenges in assigning causation. The complex nature of the problem necessitates a holistic, multidisciplinary research approach to achieve preventative and remedial management. Key aims were to determine disease distribution; significant predisposition factors; spatial trends associated with predisposition factors; microbiota associated with AOD lesions, the role and mechanisms used of consistently occurring, abundant organisms in tissue degradation. Surveys and citizen-science reports enabled determination of disease distribution. Insights into predisposition factors at landscape scale were obtained using national spatial environmental datasets. Components of the pathobiome (groups of microorganisms associated with disease) were investigated using isolation, metabarcoding, metagenomics and metatranscriptomics. Spatial patterns in incidence and occurrence of AOD were identified highly correlating with environmental predisposition factors. Stem lesions have a polybacterial cause, but the bacterial species Brenneria goodwinii is dominant and interactions with Agrilus and other bacterial species amplify its effect reproducing field symptoms. We provide new insights into polymicrobial interactions and disease expression, and develop a novel conceptual and methodological template for investigating decline diseases and adapting Koch’s postulates to address the role of the multifactorial facets of this problem.


oak decline, host predisposition, polymicrobial disease complex


Brady, C., D. Arnold, J. McDonald, and S. Denman. 2017. Taxonomy and identification of bacteria associated with Acute Oak Decline. World Journal of Microbiology and Biotechnology 33(7): 143. doi:10.1007/s11274-017-2296-4. 

Broberg, M., J. Doonan, F. Mundt, S. Denman, and J.E. McDonald, J.E. 2018. Integrated multi-omic of hostmicrobiota interactions in acute oak decline pathobiome-host interactions in acute oak decline. Microbiome 6(1): 21. doi 10.1186/s40168-018-0408-5

Brown, N., D.J.G. Inward, M. Jeger, and S. Denman. 2015. A review of Agrilus biguttatus in UK forests and its relationship with acute oak decline. Forestry 88(1): 53-63.

Brown, N., F. van den Bosch, S. Parnell, and S. Denman. 2017. Integrating regulatory surveys and public reports to map outbreaks of forest diseases: Acute Oak Decline in England and Wales. Proc. R. Soc. B 284(1859): 20170547 

Brown, N., E. Vanguelova, S. Parnell, S. Broadmeadow, and S. Denman. 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. doi:10.1016/j.foreco.2017.10.054

Cohen, W., Z. Yang, S.V. Stehman, T.A. Shroeder, D.M. Bell, J.G. Masek, H. Chengquan, and G.W. Meigs. 2016. Forest disturbance across the conterminous United States from 1985-2012: The emerging dominance of forest decline. Forest Ecology and Management 360: 242-252.

Denman, S., N. Brown, S. Kirk, M. Jeger, and J.F. Webber. 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: An International Journal of Forest Research 87(4): 535-551.

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

Denman, S., J. Doonan, E. Ransom-Jones, M. Broberg, S. Plummer, S. Kirk, K. Scarlett, A.R. Griffiths, M. Kaczmarek, J. Forster, A. Peace, P.N. Golyshin, F. Hassard, N. Brown, J.G. Kenny, and J.E. McDonald. 2017. Microbiome and infectivity studies reveal complex polyspecies tree disease in Acute Oak Decline. International Society Microbial Ecology Journaldoi:10.1038/ismej.2017.170.

Doonan J. 2016. Genomic analysis of bacterial species associated with acute oak decline. PhD thesis. School of Biological Sciences, Bangor University, UK.

Doonan, J., S. Denman, J.A. Pachebat, and J.E. McDonald. 2019. Genomic analysis of bacteria in the Acute Oak Decline Pathobiome. Microbial Genomics 5. doi:10.1099/mgen.0.000240.

Manion, P. 1981. Tree Disease Concepts. Englewood Cliffs, NJ: Prentice Hall.

Manion, P., and D. Lachance, 1992. Forest Decline Concepts. St Paul, MN: APS Press.

Pautasso, M., K. Dehnen-Schmutz, O. Holdenrieder, S. Pietravalle, N. Salama, M.J. Jeger, E. Lange, and S. Hehl-Lange. 2010. Plant health and global change—some implications for landscape management. Biological Reviews 85(4): 729-755. doi:10.1111/j.1469-185X.2010.00123.x.

Wiegand, T., and K.A. Moloney. 2004. Rings, circles, and null-models for point pattern analysis in ecology. OIKOS 104: 209-229.

Xu, X., T.D. Harwood, M. Pautasso, and M.J. Jeger. 2009. Spatio-temporal analysis of an invasive plant pathogen (Phytophthora ramorum) in England and Wales. Ecography 32(3): 504–516.