climate ready forests

Climate Ready Forests with Sally Aitken

Now I LOVE forests, and I am so pumped to drop an episode that focuses on them. Not just forests, this one delves into climate too. We don’t dwell at all on climate changes potentially destructive impacts on forest ecosystems. I think one can find that discussion just about anywhere. Nope, what I love about this is that my guest Dr. Sally Aitken takes us back to school to deliver her nuanced viewpoint that embraces the complexity of how climate has and will continue to drive change in our beloved long-lived tree species and plant communities. Then, I ultimately want to frame this discussion to provide a primer on the response adaptation strategies that exist that allow forests adapt to the changing climates they are bound to experience.

As restorationists we make decisions about which plant seeds and other propagules to introduce to the land, or in some cases, the sea to assist the natural processes for ecosystem recovery. While it may not be at the forefront of our mind in the past, considering genetics in light of habitat fragmentation, climate change, etc. is key to ensuring plant and animal populations persist and sustain themselves with minimal ongoing interventions from us. There are a variety of sourcing strategies that exist for us to mix and match to get local adaptation with diversity in mind that will buffer us against the uncertain climate futures. This topic is so relevant and compelling that it appears as a stand-alone in the 2nd Edition of the International Standards and Standards for the Practice of Ecological Restoration.

I reached out north across the border to Canada to get the opinion of Dr. Aitken who is a researcher and professor who has deep roots in the forest. Her research integrates climate modelling, seedling experiments and genomic tools to understand the processes driving local adaptation to climate in trees. I am so so grateful for the opportunity to speak with her and share that conversation with you. So many questions that have been brewing in my brain for months and even years. Like I had read the literature and formed some opinions of my own, but I still had a craving to see and hear someone like Dr. Aitken to say it out loud. You’ll see.

Sally Aitken is currently a Professor and Associate Dean, Research and Innovation, in the Faculty of Forestry at the University of British Columbia. After she obtained her PhD from the University of California, Berkeley, Dr. Aitken joined the faculty at Oregon State University before ultimately landing at University of British Columbia. In 2001, Aitken helped start the Centre for Forest Conservation Genetics at the University. Broadly, she studies the population, conservation, and ecology of forests. More specifically she is deeply involved in AdapTree and CoAdapTree Projects, which are large-scale multi-institutional, applied genomics project that use population genomics, common garden experiments and climate-mapping technologies to help guide reforestation decisions for new climates.

Sally has a distinguished list of accolades in recognition of her contribution to forest and life sciences.

  • She received the Canadian Forestry Scientific Achievement Award in 2009.

  • Due to her involvement with AdapTree project, in 2014 Aitken was awarded the International Union of Forest Research Organization’s Scientific Achievement Award for her research into the field of forest conservation genetics.

  • In 2017, Aitken was elected a Fellow of the Royal Society of Canada in the Life Science Division.

  • In 2018, she was named the recipient of the Genome BC Award for Scientific Excellence by the non-profit organization LifeSciences BC.

This episode begs for some definitions to jumpstart our mutual understanding, though Sally does an incredible job of explaining:

  1. Climate based seed transfer - adaptation strategy relies on science-based seed transfer to match seedlings/seedlots to future (projected) planting site climates.

  2. Assisted gene flow - means moving pre‐adapted trees to facilitate adaptation of planted forests to climate change. This involves aiding the movement of different genotypes of a species from within its current range to another location where it will hopefully match future climate conditions.

  3. In contrast to assisted migration, which involves planting trees farther north, outside of their current range, in order to resist actual or anticipated extinction – because they cannot keep up with the pace of climate change.

Before we begin, I want to preface this conversation by saying these issues are not black and white or meant to create a for or against debate. I will disclose some of my own opinions: Should we throw out local is best seed sourcing, no. Should we be gradually shifting what we are planting, yes. Importantly, assisted gene flow is not just a stand-alone techno fix as Dr. Aitken will expand on. It must exist within a mélange of resilience, response and resistance strategies combined to reverse environmental degradation and help pull us out of the climate crisis. It is not a substitute for decarbonization. We beed to minimize habitat fragementation. Restorative activities must continue to be ecologically responsible. Not just pulling from Western science, restoration must include local knowledge and indigenous wisdom. Lastly, we need to safeguard the ecological memory preserved in old growth forest ecosystems.

Enjoy the discussion knowing that I am going to provide links for the highlights in the show description, accessible through your podcast app or on treehugger podcast show page found at

Some questions I endeavor unpack and/or issues that emerge during this episode with Sally

  • how climate drives movement of tree populations and how seed transfer frameworks have been developed to guide replanting forests after disturbance

  • how long-lived tree species able to adapt locally across a range of environments over centuries or millennia

  • how rapidly and to what extent tree populations adapt to rapidly changing climates

  • how elevation and latitude affect or distinguish populations within a species range

  • indicators that local tree populations are maladapted or mismatched to their current climate

  • the species of interest for assisted gene flow experiments and candidate species that could become extinct if we don’t help them flee climate change

  • the tools Dr. Aitken and her collaborators utilize, important traits to observe, and data available to us to inform decision-making about what to plant where in the future

  • the policy/ethical/economic hurdles/challenges associated with this issue

  • the role that hope and doubt plays in play in our decisions and responses to climate change

  • and so much more….


Below is a quick list of resources that we mentioned during the interview: