Genomics helps Canada's forests adapt to the future
Scientists predict rapid and widespread climate change across Canada
Canada’s forests provide important ecological services, economic resources and social benefits. They also play a key role in the global carbon cycle. However, scientists predict that increasing temperatures and changes in weather patterns associated with climate change will drastically affect Canada’s forests in the near future. With the rate of projected climate change expected to be 10 to 100 times faster than the ability of forests adapt naturally, Canada’s trees are benefitting from a helping hand.
Using natural variation to strengthen future forests
Populations of a tree species that grow at different altitudes can be as genetically different as populations growing hundreds of kilometres apart.
Across Canada, researchers are using cutting-edge science – genomics – to help prepare Canada’s forests for the upcoming challenges. Genomics uses the fact that individual trees within the same species can have key differences in their genomes. Some tree populations of the same species from warm places can grow longer and faster than tree populations from colder places, but might be less cold hardy. The same species of tree in other areas may have adapted to different soil moisture conditions.
Genomic selection is already starting to be used in operational tree breeding programs, such as those developed through the FastTRAC project. In these programs, researchers first identify the best parent trees based on characteristics such as growth rate and disease resistance. Offspring from these trees are then subjected to genetic trials in test plantations and exposed to natural conditions including extreme events such as drought or late frost during the spring. The parent trees that produced the most resistant offspring are the ones with the best genetic type for that particular set of conditions – the ones that will be selected to create the next generation of trees.
What is genomics?
Genomics is the science that aims to decipher and understand the entire genetic information of an organism (i.e. plants, animals, humans, viruses and microorganisms) encoded in DNA.
Reducing the time between generations
The limiting factor in conventional tree breeding programs is time. Historically, scientists have had to wait until offspring trees started to exhibit desired traits outwardly before scientists could know which performed the best. For some beneficial traits (such as wood attributes) in Canadian conifer species, this can take up to 30 years.
Recent breakthroughs in the science of genomics, notably with the FastTRAC project, could lead to dramatically faster and better decision making. Scientists across Canada are now using computers to compare the DNA of millions of trees, then identifying genetic markers associated with insect and drought resistance, nutrient use efficiency, productivity, and wood quality. Identifying these genetic markers means that scientists already know which parent trees will produce the best offspring without needing to wait for the offspring to express a particular trait. Finding the best offspring previously took many decades, but with genomic selection, the time needed to complete the same work is significantly reduced.
Duration of breeding cycle
Graphic comparing the duration of a breeding cycle using conventional breeding versus genomic selection. With both conventional breeding and genomic selection, the crosses between trees take approximately four years. With conventional breeding it takes 20 to 25 years to evaluate the outcome, while with genomic selection it takes one to two years. With conventional breeding and genomic selection, propagation takes an additional four years. The total time for crosses, evaluation, and propagation using conventional breeding is more than 28 years, while genomic selection reduces that time to less than ten years.
Adapting to changing tree ranges
Genomics also gives trees a better chance to thrive in changing environments. For example, conditions in the northern portion of a tree species’ range might be colder or drier than in the southern portion of the range. However, as temperatures in the north increase, the local trees may struggle to adapt to the new conditions.
Traditionally, foresters have used local tree seed for planting seedlings, as local populations were generally thought to be best adapted to the climate conditions of the site. However, with a rapidly changing climate, these local populations may not be able to adapt quickly enough, and while well-established adult trees can often withstand increased stress, seedlings are highly vulnerable. If forest managers know which seeds and seedlings from the southern portion of the range would thrive in the changing northern conditions, they can strategically select the hardiest and best-adapted for planting.
Selecting and planting seedlings for changing conditions
Diagram consisting of two frames. The first frame shows the current range of a tree species, with warmer temperatures found in the southern portion of its range, and cooler temperatures found in the northern portion of its range. An arrow indicates that a seedling is selected from the southern portion of its natural range, where it’s warmer, and then planted in the cooler northern portion of its range. The second frame shows the hypothetical future range of the same tree species under warmer climate conditions. The whole tree range is located further north than in the first frame. The seedling from the first frame is found within the new tree species range, and is well adapted to the new, warmer conditions in the north.
Building a library of resources to manage for the future
Enter the researchers at the CoAdapTree project, who are providing insight to the forest managers by growing, testing, and sampling over 10,000 seedlings and trees and reading their genomes. The researchers can then look at the genomes and recommend which seeds and seedlings forest managers should plant to match both the current and projected local climate conditions of a species’ range.
CoAdapTree is just one of several Canadian projects focusing on using micro-scale solutions to macro-scale challenges. For example, the Spruce-Up project is focused on decoding the genomes and identifying natural genetic variations within existing spruce tree populations for drought, insect resistance and fibre quality. The research team will then create algorithms and other tools for forest managers to use when selecting the best growing stock. Similarly, the RES-FOR research team also uses genomics to help inform forest management, by creating mathematical models and an interactive website for forest managers.
With about 260 million spruce seedlings planted per year, spruces are the most reforested trees in Canada.
These three projects are the result of joint efforts by university and government research teams, supported by Genome Canada.
Forests of the 21st century
Advances in tree genomics are now making it possible to not only strengthen existing tree populations but also prepare Canada’s trees for new environments. As forest health is of fundamental importance in the fight against climate change, these innovative researchers are ensuring that Canada’s forests are resilient in the face of change.
Sources and information
- Alberta Government. Review of insect and disease challenges to Alberta coniferous forests in relation to resistance breeding and climate change
- Genome British Columbia. Forest technology building better renewable resources
- Isabel N., Holliday J., et al. 2019. Forest genomics: Advancing climate adaptation, forest health, productivity, and conservation. Evolutionary Applications 13(1): 3-10
- Lenz, P., Nadeau, S., et al. 2019. Multi‐trait genomic selection for weevil resistance, growth, and wood quality in Norway spruce. Evolutionary Applications 13(1):76-94
- National Forestry Database. Regeneration, Table 6.2.1. Number of seedlings planted by jurisdiction, tenure and species group. (accessed May 28, 2020)
- Natural Resources Canada–Canadian Forest Service. Distribution of tree species
- Science. January 27, 2020. Massive effort to document the genetics of European forests bears fruit
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