How UK plantations can help mitigate the climate crisis

Professor Patricia Thornley, Director of the Supergen Bioenergy Hub, responds to Patrick Barkham’s article in The Guardian on 10 March 2020: Trees on commercial UK plantations ‘not helping climate crisis’.

There is a need to be careful with the logic used in this article. Plantation forests cover a certain land area in the UK at present. Every year they absorb carbon from the atmosphere, and that is helping to regulate climate change. When the trees are mature, they are chopped down and used (that is why they were planted in the first place). So, the first thing to realise is that the carbon that is released when those trees eventually decompose is not fossil carbon, so it is not transferring carbon that was long ago locked up from the atmosphere back to the atmosphere, thereby adding to the long-term burden. Instead it is carrying out a medium-term cycling. The carbon was absorbed over the last 15 years during growth and will now (according to the report) be released in the following years (almost immediately if used as wood fuel, up to many decades if used for construction). That does not necessarily mean that the release is exacerbating climate change. If the forest area is maintained then more carbon will be sequestered in the years while that product is used. In fact, the fastest sequestration rates are in the earlier growth years, so we actually need to chop these trees down to allow the land to be freed up to do more sequestration.

To draw a parallel with which most people will be more familiar: The plantation trees operate on a timescale that is short in comparison to the increase in carbon concentration we have seen since the industrial revolution. So, you can think of the fossil fuel oil, coal and gas reserves as being like your savings account. These are your long-term stocks that you have laid down to provide a buffer against all eventualities, and squandering those by releasing to the atmosphere will have a huge negative effect on the planet, in much the same way that raiding your savings account to pay for luxuries will have a negative impact on your financial status.

But plantations work on a shorter timescale and it makes sense to think of these as more like your current account. The account balance (carbon stock) increases as we gain income and decreases as we spend. It doesn’t matter too much how low it gets before payday as long as net over the year we remain roughly in balance and don’t go overdrawn. So it is with trees and the planet. There will always be perturbations and these can seem large if we focus in on a very small timescale or land area. But the key is to look at the long-term trend over the whole planet – that is what the atmosphere sees. And if that continues to extract each year an amount of carbon that is not that dissimilar to what is released when those trees are used, that is fine. The problems arise when the carbon stock (the long-term reserves that have been laid down by the tree growth) are affected. That is generally caused by reductions in land area under forest cover or sometimes by changes in management or climate that affect the actual standing amount of biomass in a plantation – again this needs to be viewed holistically, as different plots of land will be at different points in their overall cycle.

So, yes it is best to use trees in a way that lays down carbon long term, for example in construction, but not all trees or tree parts are suitable for that. Forestry is a business and landowners grow what they know they will be able to sell. So while we all might love to increase the broadleaf coverage in the UK, this is only going to be viable if there is a market for the wood products from long-rotation forests (so, buy more hardwood flooring and less laminate!).

I am concerned about how agricultural expansion is driving deforestation in the Amazon. That is causing loss of carbon stock (raiding our planet’s carbon savings account) and limiting our capacity to absorb carbon each year (reducing the payments into our planetary carbon current account). But I’m not worried about whether we return carbon that we removed from the atmosphere over the last 15 years in the next four, 10 or 25 years. That is like getting worried about whether my annual salary is paid weekly or monthly. It doesn’t actually matter that much in the long run as long as we do maintain the area of land that is forested and use tree species that are sensible for the location.

Important notice for all academic journal reviewers

Patricia Thornley from Aston University has published an article on LinkedIn with a personal reflection on the value of peer review in science and the risks associated with changing this system as we move towards more open access.

Yesterday I worked with colleagues to finalise our author response to reviewer comments and submit the revision of our most recent paper. The reviewers (three of them) all agreed it was a good paper (phew!), but they each took the time to challenge us about what we had done, why and how we had described it. They meticulously scrutinised our figures and data, making helpful suggestions about how presentation of these could be improved. They encouraged us to go further with our conclusions, take a risk and really spell out the consequences. The reviewer comments alone ran to several pages and so it took quite a bit of effort to consider, adapt, revise and respond.

But I can honestly say it was worth it – the paper is much improved and the revision will be submitted next week. So I mainly wanted to say a very public thank-you to those three reviewers for giving so generously of their expertise and their time. I honestly felt we were ‘standing on the shoulders of giants’, being supported by our scientific community to improve our work, our message and what we do next.

But I also wanted to extend that thank-you to all journal reviewers. As editor-in-chief of an Elsevier journal, I see evidence every day of experienced and insightful reviewers giving freely of their time to improve the knowledge base in our community.

So, to each and every one of you who has ever reviewed a paper for Biomass and Bioenergy or any other journal: THANK YOU! You are so important to the integrity and credibility of our science.

Yet I worry about reviewers (the unsung heroes of this peer-review process): about the demands we put on them, with so many invitations to read so many papers with authors demanding increasingly short turnaround times.

And I worry about open access. I do a lot of work on policy relevant issues and so I am a really big fan of making science more accessible. But that requires more than just putting scientific ‘gobbledygook’ on open websites. A little knowledge can be a dangerous thing and I think it is important that we put into the public domain material that we are absolutely confident is robust and that we equip readers with the tools to understand the implications. We have seen in recent years how easy it is for fake news to become accepted truth, and recent rises in measles cases have been a sharp reminder of the ethical concerns we should have about ensuring that material put in the public domain is appropriately explained to those who may read it and (heaven forbid!) actually act on it. So, yes let’s put more science in the public domain, but let’s also ensure that what we put out is independent, rigorous and appropriately interpreted.

I work in bioenergy, a very contentious area with different opinions on the sustainability issues. Some days I see papers that I really like, some days I see some that make me think hard (the best ones!) and some days I see some that just make me roll my eyes and think “Oh no, not another one …”. I can (usually) see through the different levels of rigour and analysis and know which ones to value in my area, but I wouldn’t be able to discern the good from the indifferent in say microbiology or artificial intelligence.

The public trusts scientists and it is really important that we respond to that trust by taking care to share robust, rigorous, peer-reviewed science with an appropriate level of guidance and interpretation. So I worry about how we maintain that trust in an open access world, where the scientists are customers paying to have their own work put in the public domain and exercising consumer rights in their choice of journal and their expectations of turnaround time and favourable outcomes.

And that brings me back to reviewers. I have a willing database of thousands of reviewers in my journal. They know their job is to review, to challenge and to uphold the standards of scientific integrity on which we all depend. Does that relationship change when they review a paper for open access publication? Do they still have faith that the editor will take on board their valuable concerns even if it means turning away an author income stream? Do authors still respect the reviewers’ and editors’ contribution when they are consumers not applicants? Do we get the same level of ‘value added’ to the raw science that I have just experienced this week when we prioritise reviewers who can review quickly to meet promised journal benchmarks over those who review thoroughly?

I don’t know the answers to these questions, and so it makes me incredibly nervous that we are embarking upon a change to the publishing system that will alter those finely balanced relationships between author, reviewer and editor, without fully understanding the potential consequences.

Disclaimer: Note that while I am a professor at Aston University, Director of the Supergen Bioenergy Hub and Editor-in-Chief on an Elsevier journal, these musings are entirely my own independent thoughts – as they rightly should be!

Photo credit: Flickr/afagen