Johanna Witzell

Professor

Department of Forestry and Wood Technology Faculty of Technology

johanna.witzell@lnu.se

+46 470-70 88 25

+46 70-230 90 56

Johanna Witzell: The threats to forest health

FILM | Climate change in our time means that forest damage will increase in the future. Pests such as fungi and insects find it easier to gain a foothold and spread, which could lead to the loss of forests.

Johanna Witzell has always been interested in forests and nature. She now researches forest health, focusing specifically on the early signs that trees have been attacked. This is crucial for detecting and stopping pests in time.

My research groups

My ongoing research projects

Publications

Article in journal (Refereed)

Leverkus, A.B., Medina, M., Lázaro-gonzález, A., Levy, L., Lorente-casalini, O., et al. (2026). Drivers of seedling emergence and early growth of 12 European oak species : Results from a cross-continental experiment. Forest Ecology and Management. 599.
Status: Published
Castagneyrol, B., Augustinus, B.A., Devetak, Z., Dogan, T., Drenkhan-maaten, T., et al. (2026). On the incidental exposure of the general public to invasive forest pests through mainstream media. Urban Forestry & Urban Greening. 120.
Status: Published
Knapp, D., Sunde, J., Bakhshiganje, M., Witzell, J. (2025). Bacterial Communities Associated With Acute Oak Decline of Sessile Oak (Quercus petraea) in Southern Sweden. Environmental Microbiology Reports. 17 (6).
Status: Published
Paletto, A., Sergiacomi, C., Marzano, M., Avdibegovic, M., Belka, M., et al. (2025). Collaborative approaches to urban tree biosecurity : Stakeholder's perceptions, actions and social networks. Urban Forestry & Urban Greening. 105.
Status: Published
Piispanen, J., Bergmann, U., Karhu, J., Kauppila, T., Witzell, J., et al. (2025). Effect of leaf chemicals from susceptible and resistant alternate hosts of Cronartium on in vitro germination of aeciospores of Cronartium pini and C. ribicola. Baltic Forestry. 31 (1).
Status: Published
Jürisoo, L., Agan, A., Tedersoo, L., Witzell, J., Selikhovkin, A., et al. (2025). Fungal Assemblages in Northern Elms : Impacts of Host Identity and Health, Growth Environment, and Presence of Dutch Elm Disease. Microbial Ecology. 88.
Status: Published
Lopez-garcia, N., Romeralo, C., Andersen, C.B., Rönnberg, J., Grenville-briggs, L.J., et al. (2025). Metabarcoding reveals rhizosphere microbiome shifts between healthy and declining Quercus robur trees. Rhizosphere. 34.
Status: Published
Piispanen, J., Bergmann, U., Karhu, J., Kauppila, T., Witzell, J., et al. (2025). Temporal and spatial variation in chemical composition of susceptible and resistant alternate hosts of Cronartium pini, Melampyrum sylvaticum and M. pratense. European journal of plant pathology. 173. 89-97.
Status: Published
Piispanen, J., Bergmann, U., Karhu, J., Kauppila, T., Witzell, J., et al. (2025). Lack of induced chemical changes in leaves of susceptible alternate hosts of Cronartium spp. after inoculation by Cronartium pini and C. ribicola. European journal of plant pathology. 172. 467-474.
Status: Published
Dorado, F.J., Matsiakh, I., Camison, A., Olaizola, J., Romeralo, C., et al. (2025). Methyl jasmonate spray for the protection of broad-leaf trees against oomycete and fungal pathogens. Journal of Plant Diseases and Protection. 132 (2).
Status: Published
Puertolas, J., Villar-salvador, P., Andivia, E., Ahuja, I., Cocozza, C., et al. (2024). Die-hard seedlings. A global meta-analysis on the factors determining the effectiveness of drought hardening on growth and survival of forest plantations. Forest Ecology and Management. 572.
Status: Published
Piispanen, J., Bergmann, U., Karhu, J., Kauppila, T., Witzell, J., et al. (2024). Diversity and abundance of culturable fungal endophytes in leaves of susceptible and resistant alternate hosts of Cronartium pini and C. ribicola. European journal of plant pathology. 170 (1). 79-89.
Status: Published
Medina, M., Reyes-martin, M.P., Levy, L., Lazaro-gonzalez, A., Andivia, E., et al. (2024). Ex situ germination of European acorns : data from 93 batches of 12 Quercus species. Annals of Forest Science. 81 (1).
Status: Published
Macaya-sanz, D., Witzell, J., Collada, C., Gil, L., Martin, J.A. (2023). Core endophytic mycobiome in Ulmus minor and its relation to Dutch elm disease resistance. Frontiers in Plant Science. 14.
Status: Published
Franic, I., Allan, E., Prospero, S., Adamson, K., Attorre, F., et al. (2023). Climate, host and geography shape insect and fungal communities of trees. Scientific Reports. 13 (1).
Status: Published
Riit, T., Cleary, M., Adamson, K., Blomquist, M., Burokienė, D., et al. (2023). Oomycete Soil Diversity Associated with Betula and Alnus in Forests and Urban Settings in the Nordic–Baltic Region. Journal of Fungi. 9 (9).
Status: Published
Youssef, K., Dambrauskaite, M., Witzell, J., Rönnberg, J. (2023). Survey Study Reveals High Prevalence of Heterobasidion Root Rot Infection in Scots Pine (Pinus sylvestris) Stands Established on Seemingly Low-Risk Sites. Forests. 14 (5).
Status: Published
Witzell, J., Sunnerstam, C., Hansson, T. (2023). Vaccination of Elms against Dutch Elm Disease : Are the Associated Epiphytes and Endophytes Affected?. Journal of Fungi. 9 (3).
Status: Published
Martinez-arias, C., Witzell, J., Solla, A., Antonio martin, J., Rodriguez-calcerrada, J. (2022). Beneficial and pathogenic plant-microbe interactions during flooding stress. Plant, Cell and Environment. 45 (10). 2875-2897.
Status: Published
Benavent-celma, C., López-garcía, N., Ruba, T., Ściślak, M.E., Street-jones, D., et al. (2022). Current practices and emerging possibilities for reducing the spread of oomycete pathogens in terrestrial and aquatic production systems in the European Union. Fungal Biology Reviews. 40. 19-36.
Status: Published
Romeralo, C., Martin-garcia, J., Martinez-alvarez, P., Jordan munoz-adalia, E., Goncalves, D.R., et al. (2022). Pine species determine fungal microbiome composition in a common garden experiment. Fungal ecology. 56.
Status: Published
Franic, I., Prospero, S., Adamson, K., Allan, E., Attorre, F., et al. (2022). Worldwide diversity of endophytic fungi and insects associated with dormant tree twigs. Scientific Data. 9 (1).
Status: Published
Felton, A., Felton, A.M., Wam, H.K., Witzell, J., Wallgren, M., et al. (2022). Forest biodiversity and ecosystem services from spruce-birch mixtures : The potential importance of tree spatial arrangement. Environmental Challenges. 6.
Status: Published
Witzell, J., Decker, V.H.G., Agostinelli, M., Romeralo, C., Cleary, M., et al. (2022). Aspen Leaves as a "Chemical Landscape" for Fungal Endophyte Diversity - Effects of Nitrogen Addition. Frontiers in Microbiology. 13.
Status: Published
Cleary, M., Blomquist, M., Marchand, M., Witzell, J. (2021). Oomycetes in rhizosphere soil of ornamental plants from retail nurseries in Southern Sweden. Forest Pathology. 51 (2).
Status: Published
Pötzelsberger, E., Gossner, M.M., Beenken, L., Gazda, A., Petr, M., et al. (2021). Biotic threats for 23 major non-native tree species in Europe. Scientific Data. 8 (1).
Status: Published
Agostinelli, M., Nguyen, D., Witzell, J., Cleary, M. (2021). Mycobiome of Fraxinus excelsior With Different Phenotypic Susceptibility to Ash Dieback. Frontiers in Forests and Global Change. 4.
Status: Published
Agostinelli, M., Cleary, M., Martín, J.A., Albrectsen, B.R., Witzell, J. (2018). Pedunculate Oaks (Quercus robur L.) Differing in Vitality as Reservoirs for Fungal Biodiversity. Frontiers in Microbiology. 9.
Status: Published
Grenville-briggs, L.J., Kushwaha, S.K., Cleary, M.R., Witzell, J., Savenkov, E.I., et al. (2017). Draft genome of the oomycete pathogen Phytophthora cactorum strain LV007 isolated from European beech (Fagus sylvatica). Genomics Data. 12. 155-156.
Status: Published
Gunulf åberg, A., Witzell, J., Rönnberg, J. (2016). Risk of False Positives during Sampling for Heterobasidion annosum s.l.. Plant Disease. 100 (1). 175-179.
Status: Published
Blumenstein, K., Macaya-sanz, D., Martín, J.A., Albrectsen, B.R., Witzell, J. (2015). Phenotype MicroArrays as a complementary tool to next generation sequencing for characterization of tree endophytes. Frontiers in Microbiology. 6.
Status: Published
Martín, J.A., Witzell, J., Blumenstein, K., Rozpedowska, E., Helander, M., et al. (2013). Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in Elms (Ulmus spp.). PLOS ONE. 8 (2).
Status: Published
Jensen, A.M., Löf, M., Witzell, J. (2012). Effects of competition and indirect facilitation by shrubs on Quercus robur saplings. Plant Ecology. 213 (4). 535-543.
Status: Published
Farnier, K., Bengtsson, M., Becher, P.G., Witzell, J., Witzgall, P., et al. (2012). Novel bioassay demonstrates attraction of the white potato cyst nematode Globodera pallida (Stone) to non-volatile and volatile host plant cues. Journal of Chemical Ecology. 38 (6). 795-801.
Status: Published
Schiebe, C., Hammerbacher, A., Birgersson, G., Witzell, J., Brodelius, P.E., et al. (2012). Inducibility of chemical defenses in Norway spruce bark is correlated with unsuccessful mass attacks by the spruce bark beetle. Oecologia. 170 (1). 183-198.
Status: Published
Edenius, L., Mikusiński, G., Witzell, J., Bergh, J. (2012). Effects of repeated fertilization of young Norway spruce on foliar phenolics and arthropods : implications for insectivorous birds’ food resources. Forest Ecology and Management. 277. 38-45.
Status: Published
Witzell, J., Berglund, M., Rönnberg, J. (2011). Does temperature regime govern the establishment of Heterobasidion annosum in Scandinavia?. International journal of biometeorology. 55 (3). 275-284.
Status: Published
Srivastava, V., Schinkel, H., Witzell, J., Hertzberg, M., Torp, M., et al. (2007). Downregulation of high-isoelectric-point extracellular superoxide dismutase mediates alterations in the metabolism of reactive oxygen species and developmental disturbances in hybrid aspen. The Plant Journal. 49 (1). 135-148.
Status: Published
Stenberg, J.A., Witzell, J., Ericson, L. (2006). Tall herb herbivory resistance reflects historic exposure to leaf beetles in a boreal archipelago age-gradient. Oecologia. 148 (3). 414-425.
Status: Published
Strengbom, J., Witzell, J., Nordin, A., Ericson, L. (2005). Do multitrophic interactions override N fertilization effects on Operophtera larvae?. Oecologia. 143 (2). 241-250.
Status: Published
Nordin, A., Strengbom, J., Witzell, J., Näsholm, T., Ericson, L. (2005). Nitrogen deposition and the biodiversity of boreal forests : implications for the nitrogen critical load.. Ambio. 34 (1). 20-24.
Status: Published
Witzell, J., Kuusela, T., Sarjala, T. (2005). Polyamine profiles of healthy and parasite-infected Vaccinium Myrtillus plants under nitrogen enrichment. Journal of Chemical Ecology. 31 (3). 561-575.
Status: Published
Witzell, J., Shevtsova, A. (2004). Nitrogen-induced changes in phenolics of Vaccinium myrtillus : implications for interaction with a parasitic fungus. Journal of Chemical Ecology. 30 (10). 1937-1956.
Status: Published

Conference paper (Refereed)

Dahy, B., Sengün, E., Witzell, J., Fransson, J. (2025). Mapping Boreal Forest Vitality Using Drone-Based Multispectral Time-Series and Object-Based Classification. International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences ISPRS Archives. 81-86.
Boman, G., Dahy, B., Sengün, E., Witzell, J., Fransson, J. (2025). Detecting Root Rot Infected Norway Spruce Trees Using Multispectral and LiDAR UAV Data. International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences ISPRS Archives. 33-38.

Chapter in book (Refereed)

Witzell, J., Romeralo tapia, C., Aldea, J., Löf, M. (2022). Forest diversity and productivity : Implications for forest health in future climates. Forest Microbiology. Vol 2. Forest Tree Health. Academic Press. 49-59.

Article, review/survey (Refereed)

Woodward, S., Amin, H., Martin-garcia, J., Solla, A., Diaz-vazquez, R., et al. (2025). Host-Pathogen Interactions in the Pine-Fusarium circinatum Pathosystem and the Potential for Resistance Deployment in the Field. Forest Pathology. John Wiley & Sons. 55 (2).
Status: Published
Lankinen, A., Witzell, J., Aleklett, K., Furenhed, S., Green, K.K., et al. (2024). Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review. Agronomy for Sustainable Development. Springer. 44 (2).
Status: Published
López-garcía, N., Romeralo, C., Rönnberg, J., Witzell, J. (2024). Control and management of Phytophthora damage in forestry : A systematic mapping study. Forest Pathology. John Wiley & Sons. 54 (4).
Status: Published
Felton, A., Petersson, L., Nilsson, O., Witzell, J., Cleary, M., et al. (2020). The tree species matters : Biodiversity and ecosystem service implications of replacing Scots pine production stands with Norway spruce.. Ambio. Springer. 49 (5). 1035-1049.
Status: Published

Chapter in book (Other academic)

Witzell, J., Romeralo, C., Martín, J.A. (2021). Translational research on the endophytic microbiome of forest trees. Forest Microbiology, Volume One : Tree Microbiome: Phyllosphere, Endosphere and Rhizosphere. Elsevier. 385-394.

Article in journal (Other (popular science, discussion, etc.))

Normark, E., Witzell, J. (2022). Nya och gamla skogsskötselstrategier och skogsskador. Kungl. Skogs- och lantbruksakademiens tidskrift. 161 (7). 40-43.
Status: Published