Forest Genetics and Diversity

In the Forest Genetics and Diversity research gruoup our studies cover a diverse set of woody species from temperate, tropical and boreal climates from many genera including: Abies, Acacia, Acer, Adansonia, Alnus, Betula, Carpinus, Castanea, Coffea, Corylus, Cratagus, Cytisus, Dalbergia, Eusideroxylon, Fagus, Fraxinus, Juglans, Larix, Malus, Parkia, Picea, Pinus, Prunus, Pseudotsuga, Quercus, Rosa, Sorbus, Tectona, Theobroma, Thuja, Tilia, Vitellaria, Ulmus.

Focus in our research is on fitness, adaptive and evolutionary processes, but also on economic and social values. We use a combination of in situ studies, common garden trials, genomic techniques, dendroecology and ecophysiology, while e-DNA is an important tool in our studies of biodiversity.

In recent years, our research has expanded to detailed studies of host-pathogen-pest interactions and the effects of the microbiome on the health and stability of trees. Novel methods based on use of drones and deep learning are being tested for more effective phenotyping, while new techniques for DNA sequencing and data analysis are being implemented in our genomic studies.

Together with national and international partners across Europe, North America, Africa and Asia, we implement a wide range of projects from timber and Christmas tree breeding to interdisciplinary projects in cooperation with forest and landscape historians, ecologists and social scientists. Climate change adaptation and mitigation are integrated components in most of the projects.

• Major ongoing projects
• Selected ongoing projects
• Selected past projects

Our projects vary in spatial and temporal scale and in the level of interactions among flora, fauna and fungi. The research group manages a large number of field trials and the Hørsholm Arboretum (arboretet.dk) utilized for teaching and research.

On-going projects involve activities in Scandinavia, but also in several African and Asian countries. Many projects involve international cooperation with scientists from Europe, US, Africa or Asia.

Major ongoing projects

Species and geographic focus

Research on abiotic adaption (soil and climate) covers an array of species: native Danish wood plant species growing in forests and open landscape, native and exotic forest timber species, Christmas/greenery trees. In total we work with domestication of more than 30 species at different levels of intensity. On biotic adaptation (pests and pathogens), we have on-going quantitative genetic and genomic research on the interaction between host species and their pests and pathogens (between Fraxinus sp. and Hymenoscyphus fraxineus, Abies nordmanniana and various insects and pathogens, Picea sitchensis and green aphids, and Ulmus sp. and Dutch elm disease).  We also study interactions between native and invasive species at the genetic level, presently looking at the genetic implications of introduced Cytisus scoparius invading open landscapes.Activities in South-East Asia and Africa.

On-gong research activities cover sub-Saharian species of large local socio-economic and ecological value, with main focus on trees in the West-african parklands and sahelian areas (including Adansonia digitata, Parkia biglobosa, Vitteralia paradoxa, Acacia senegal).  On conservation of tropical trees species, we work with partners in South-East Asia and Africa on application of genetic markers and novel genomic tools to strengthen local efforts on conservation and sustainable use of endangered or vulnerable species including Dalbergia and Eusideroxylon zwageri.

Danish activities 

The research group is a key partner in Danish activities on breeding programs of quality timber, landscape species and superior Christmas trees/greenery, but also holds substantial experience on domestication and conservation of tropical species. In relation to a transition towards bio-based economies, we intend to analyze and test if a wider use of species and planting material may integrate higher productivity with environmental and aesthetic values into landscape bioenergy plantings.

Projects

FADE - Fighting Ash Dieback with Endophytes

Funded by The Danish Council for Independent Research (DFF) DKK 3.469.536

Ash dieback caused by the fungus Chalara fraxinea was first recorded in Denmark in 2002, and it has thus far affected up to 90% of ashes in the country. Despite threatening European forestry for more than two decades, not much is known about the disease or an effective disease management. Recently, a small number of ash trees showing different degrees of resistance to the disease were found in populations of native Danish ash.

Although Danish experiments suggested that the resistance is likely to be genetically controlled, other extrinsic factors might as well contribute to the resistance. For example, endophytes – microbial endosymbionts that live within a plant without causing apparent disease – are long known to enhance disease resistance in trees. The presence of specific endophytes enhances resistance to Dutch elm disease in elm and to white pine blister rust in white pine.

Therefore, this project is established with three objectives: (I) to characterize an endophytic community associated with ashes resistant and susceptible to ash dieback in order to study interplay between endophytes, the hosts, and the pathogen (II) to isolate the endophytes and utilize them as a biological control agent (III) to understand defence mechanisms elicited by the endophytes. The knowledge gained from this project will be valuable for understanding the composition of endophytes and their involvement in resistance to ash dieback, but will also be important for management of the disease as well as conversation of ashes.

The Caspian forests of Iran: A gene pool for the adaptation of European forests?

Funded by Villum Fonden DKK 5.621.778  

The project will test to which extend the Caspian forests in Iran contain genetic potential for our European forests and their ability to adapt to future challenges in terms of climate change, new diseases and pests. A more general aim is to contribute to the understanding of the evolutionary processes our forest tree species have undergone as a function of selection pressure (ice ages/human influence) and isolation (refugia conditions) and how these processes have influenced genetic diversity and adaptive potential of the tree species.

The project will collect seed from 6 selected tree species in the Caspian forests, each represented by up to 9 provenances. The seed will be used to establish provenance trials in afforestation areas in Denmark and Iran. The trials will also include European/Danish reference provenances. The provenance trials will be a unique infrastructure for the next decades for studies of forest tree adaptability and climate change. The test material will be subject to quantitative genetic analyses in additional fast-track single tree plot trials. All 6 species will be analyzed by DNA analyses to compare genetic diversity between the Caspian and Danish/European forests, as well as to describe the population genetic structure of the source populations. 

Trees for the future forests 

Funded by Villum Fonden DKK 5.900.000

This project addresses how to support high adaptive potential of trees that can grow well in the uncertain future climate. The long term health and fitness of our future forest trees are challenged by the predicted increasing temperatures, heavier and more frequent climate extremes (storms, droughts or floods), competition from new invasive species, and exposure to new pests and pathogens. On the other hand, global warming could also lead to increased productivity if the trees can utilize longer growing seasons. Based on the above background, the present project study how to select, improve (or prepare) the trees for the future forests?

We will use genetic and genomic approaches to study adaptive processes in trees. Time series observations from a large body of existing field trials will be combined with ecophysiological tests and front edge genomic techniques in the search for new understanding.

An important part of the project involves practical applicability of identified solutions. We will design genetic management solutions, predict their ecological and economic costs, risks and benefits. New trials will be established and guidelines for breeding of major tree species developed. Results from the project will help guide important decision on:  Forestry practise that support on-going adaptation, Breeding for trees with high climate resilience and adaptability and Development of trees with high innate robustness against pest and pathogens.

Unravelling ash-dieback resistance: insights from single-cell analysis of tolerant and susceptible ashes across evolutionary divergent clades

Funded by The Danish Council for Independent Research (DFF) DKK 5.136.470

The invasive ash dieback pathogen, Hymenoscyphus fraxineus, causes severe damage on European ash. Our previous research has documented significant differences in susceptibility among clones of Fraxinus excelsior, but also among Fraxinus species of different evolutionary clades. In this project we hypothesize that phylogenetically related ash species with resistance against H. fraxineus share cellular defence responses that protect them against this pathogen.

The project aims are to explore the infection process of H. fraxineus, and compare cytological and molecular mechanisms among both resistant and susceptible species of Fraxinus and F. excelsior clones. The findings will reveal factors responsible for host resistance with the ultimate aim to strengthen future ash breeding. This is accomplished by i) in vivo comparison of cytological responses to infection by fluorescent-tagged H. fraxineus strains ii) identification of molecular defence mechanisms/pathways that moderate resistance to the fungus using single-cell transcriptomic analysis, and iii) comparison of cell wall composition using analytical chemistry. The results will increase the likelihood of identifying markers for breeding.

Selected ongoing projects

Abies bornmülleriana as a more environmental friendly Christmas tree species

Funded by The Danish Agrifish Agency DKK 2.917.648

Abies bornmülleriana is a fir species closely related to Nordmann fir. It was tested as Christmas tree producer together with Nordmann fir in the 1990’s and actually showed very promising results compared to the all-dominating Nordmann fir. However, the breeding and research efforts have since the early 1990’s and onwards been focused on Nordmann fir, although in the later years, more attention has again been given to A. bornmülleriana, because it seems less susceptible to the silver fir woolly adelgids (Dreyfusia nordmannianae). The latter is the most serious problem for Christmas tree production with Nordmann fir in Denmark and making it very hard to avoid use of pesticides.

Due to the very limited research and breeding efforts for bornmülleriana, only one single clonal seed orchard exist for the species (FP.267 – Kongsøre) consisting of originally 80 trees (=clones) selected phenotypically for moderate height growth, narrow with, symmetry, many internodial branches and buds plus healthy green needles and no needle loss. The seed orchard was established in 1995 and started to give seed in 2006. Our goal is, with this pre-selected plant material, to use a combination of conventional breeding methods and DNA-markers, thereby making seeds available from the best clones with regards to Christmas tree production. These seed will then be used for the production of clonal plants using somatic embryogenesis (SE). In this way the starting point for production of SE plants of bornmülleriana will be the best possible, by having added a selection based on quantitative genetics methodology to the original phenotypical selection.

Allanblackia stuhlmannii - a new plant oil species in East Africa

Funded by Godfred Birkedal Hartmanns Familiefond DKK 298.000

ClimCocoa

Funded by Danida DKK 1.276.497

Cocoa (Theobroma cacao L.) is the third highest export commodity of Ghana and represents the most important source of revenue for numerous small scale farmers. Climate change (CC) in the form of higher temperatures and reduced rainfall is expected to adversely affect cocoa productivity and reduce the area suitable for cocoa cultivation in Ghana, but the extent and underlying mechanisms are not well understood. The CLIMCOCOA project aims to develop a comprehensive understanding of the impacts of CC on the socio-biophysical bases of cocoa systems in Ghana, and assess the role of agroforestry (AF) as a model for climate smart agriculture in Ghana.

We will use a multidisciplinary approach to investigate the socio-biophysical limitations and options for cocoa cultivation under CC, and to assess institutional and socio-economic factors that favor or limit adoption by farmers of innovative management options.

CLIMCOCOA will enhance farmers’ capacity to be more resilient to CC impacts on cocoa in Ghana, and build capacities of local researchers to be able to apply state of the art modelling tools to assess CC impact.

Conservation of vulnerable timbers in REDD

Alarming rates of deforestation and ecosystem degradation add to global warming, and sustainable management of forests is therefore an important part of the REDD concept. REDD activities shall both reduce CO2 emissions, conserve biodiversity and secure future livelihoods for local populations.

The present project aims at increasing the conservation value of REDD programmes by testing positive and easy applicable tools for planning and monitoring based on novel biodiversity assessment methods. The project targets Dalbergias - valuable, highly vulnerable timer species becoming increasingly rare due to illegal logging and habitat degradation. A strategy for sustainable use and management of Dalbergia is needed as a part of overall forest conservation strategy in Cambodia and adjacent countries.

Building on a larger on-going study of diversity and evolutionary potential in natural Dalbergia populations, this project will develop and test applications of novel biodiversity assessment tools for identifying areas and populations especially vulnerable to future climate change. Further, the project will test the use of DNA fingerprinting methods to monitor the exact species identity and geographic origin of traded timber. This can be an operation tool suitable for use in global certification schemes and/or FLEGT programmes.

Detection of rare species of orchid with DNA from soil samples

Funded by Godfred Birkedal Hartmanns Familiefond DKK 600.00

Genetic diversity and adaptability of Calabrian forest trees

Funded by Godfred Birkedal Hartmanns Familiefond DKK 1.450.000

About 30 years ago we found a genetic explanation for why silver fir (Abies alba) of Calabrian origin showed an extraordinary vitality and adaptability, when grown outside its home region (including Denmark). It turned out that silver fir from this southern Italian region had a higher genetic variability compared to fir from the rest of the species' range. This startling discovery has since been explained by genetic drift in the different refugia during the last Ice Age, where the Calabrian refugium ensured good conditions for the species' “wintering”, maintaining the natural genetic variation, while the refugia(s) from which silver fir immigrated to Central and northern Europe, have undergone genetic bottlenecks due to poor climate conditions during the last ice age with loss of genetic variation and thus adaptability.
The objective of the project is to carry out studies of genetic variability and adaptability of silver fir and beech, from Calabria using new DNA analysis methods (not available in the 1980's) and to establish some provenance trials in Denmark.

Genome-based analysis and diagnostic methods as a tool in the Arboretum tree collection and research

Funded by Godfred Birkedal Hartmanns Familiefond DKK 222.500

Healthy ash trees: analysis of the interaction between pathogen and host

Funded by Godfred Birkedal Hartmanns Familiefond DKK 88.000

The Asian pathogen, Hymenoscyphus fraxineus, has in recent years caused severe harm to the Danish ash forests, while in Asia the fungus appears to be a harmless decomposer of ash leaves from native Asian ashes. In this study, we test whether the Danish invasive fungal population contains differences in aggressiveness among isolates cultured from fruiting bodies collected from the forest floor.

Healthy ash forests III - from research to practice: The use of health-related genetic markers in ash

Funded by Godfred Birkedal Hartmanns Familiefond DKK 203.136

Together with partners from the UK, we have found a number of genetic markers that are correlated with the ability to tolerate ash dieback. This project investigates how these markers are inherited from parents to offspring and how the markers can be used in practice at a wider scale.

Improved communication of the Arboretum's collections to the public

Funded by 15. juni fonden DKK 296.000

Plant Ecophysiology equipment

Funded by Godfred Birkedal Hartmanns Familiefond DKK 349.000

Plant selection in East Africa

Funded by Godfred Birkedal Hartmanns Familiefond DKK 800.000

Resistance to ash dieback based on help from naturally occurring endophytic fungi

Funded by Godfred Birkedal Hartmanns Familiefond DKK 385.147

Resistant ash trees seem to harbour beneficial fungi, which may have an inhibitory effect on the harmful ash dieback pathogen. The project identifies substances, which the apparently beneficial fungi secrete, and examines how these inhibit the growth of ash dieback. The potential of these fungi to combat ash dieback in susceptible ashes is also examined. 

The Greenlandic Arboretum – II: A greener Greenland?

Funded by Godfred Birkedal Hartmanns Familiefond DKK 312.000

Selected past projects

Denmarks future tree species

Funded by Godfred Birkedal Hartmann DKK 237.000