AdaptTree: The adaptability of forest trees to a changing climateThe adaptability of forest trees to a changing climate mainly depends on two requisites: firstly, on the genetic variation of the respective tree species, i.e. on the availability of genes or alleles (variants of genes) to cope with the warmer climate. Secondly, on the epigenetic status of the responsible genes, that is whether genes are switched on or off. Within the last 20 years, is has been shown that epigenetic processes control many tree characteristics that are responsible for adaptation to environmental conditions. For example, evidence for epigenetic effects within in vitro experiments has been found for bud burst, the start and ceasing of growth and frost hardiness. In these cases, temperature and day length during pollination, zygotic embryogenesis and seed development were found to be triggers for the behaviour of the obtained seedlings.
Here, we aim to test for the effects of weather conditions during pollination, embryogenesis and seed development on the performance of seedlings from open-pollinated seed orchards and seed stands. Extreme environmental conditions that were found in different seed years represent the environmental trigger. In a two year nursery trial with two different treatments (A-water deficit treatment; B-optimal water treatment) we characterise various growth measures (e.g. shoot dry weight, root dry weight, total weight, height, stem diameter, root length), phenological behaviour (e.g. timing of bud burst, growth cessation, bud set) and resistance to drought and frost.
The final analysis of these traits will help to predict the impact of weather conditions on adaptation to future climates. If we can confirm the paramount effect of epigenetics on the climatic adjustment of tree species within our in vivo experiment, new adaptation measures could be implemented: for example, new seed orchards could be established in warmer regions of Austria to produce seeds for regions where a severe warming effect is predicted. Also, seed harvest years could be classified according to the temperatures during seed production: seeds produced in warmer years could be assigned to regions where higher temperatures are expected and seeds produced in colder years could be restricted to specific regions.
The central objectives are:
- Characterisation of epigenetic effects in seed harvests that were produced at the same seed stands or seed orchards, but under strongly different climatic conditions at the time of pollination and seed maturation within the frame of a nursery experiment for three native tree species: Norway spruce, European larch, and Scots pine.
- To test for the first time, if pollination/seed maturation under a warm and dry environment, preconditions the offspring to a better resistance against stress factors associated with temperatures (e.g. drought)