Ian Parsons spent 20 years as a ranger. He now writes books and articles on wildlife. He has contributed many articles to this blog – click here and find his guest blogs (in an alphabetical list).
When it comes to establishing new woodland, it is fair to say that I would far prefer this done by encouraging natural regeneration rather than by actually planting trees. Previous blogs on this site illustrate my views on this, as does my chapter in the book Great Misconceptions – Rewilding Myths and Misunderstandings, in which I suggest that financial considerations may be a driver in decisions by organisations to look at using tree planting rather than encouraging natural regeneration on schemes they are involved in.
But, that doesn’t mean that I am against tree-planting schemes, planting trees can be a good thing to do, a very good thing indeed – I’ve done plenty of it myself – it can be a great way of involving people in a local scheme, encouraging their buy in to the project and it can also generate income for people, be that through direct employment in the implementation of the scheme or through grant payments. But that doesn’t mean we shouldn’t ask questions.
And the question I want to ask, and it is a question I will repeat many times in this blog, is:
What is the environmental and carbon cost of large scale tree planting schemes?
It is a question that I feel we should be trying to answer, yet it is a question that seems to be heavily avoided, with people seemingly not wanting to answer it. Which of course begs the question, why don’t we want to answer the question?
Most, if not all, of the large tree-planting schemes that we hear about are being done with the aim of tackling the climate crisis, phrases such as mitigating climate change and carbon offsetting are often used. This is, of course, a fantastic objective although we shouldn’t let it hide the fact that the best thing we can do for the climate crisis is to immediately curtail our carbon emissions. But it is phrases such as ‘saving the planet’ and ‘carbon offsetting’ that make the question ‘What is the environmental and carbon cost of large scale tree planting schemes?’ even more relevant. How can we be sure if a scheme is offsetting carbon if we don’t know what the scheme’s own carbon cost is. How many years do the planted trees have to be in the ground to offset the scheme’s own carbon cost, before they can offset anyone else’s carbon cost?
The only way to answer my question is for a full environmental and carbon audit of every stage of a tree-planting scheme, from the sourcing of tree seeds through to them being planted in the ground. I accept that is quite an undertaking, but these schemes are already very well planned, so build the question into the planning stage of the scheme. A bit of extra work perhaps, but we want to get this right, we want to be sure that large scale tree-planting schemes are as good as we think they are. But whenever I ask the question ‘What is the environmental and carbon cost of large scale tree planting schemes?’ I get push back. My question gets answered with other questions (whatever happened to the phrase never answer a question with a question?), questions that seem to me to be a way of dodging my original one. It is a tactic that we often see from politicians when they don’t want to answer a question, we expect it from them, but it always comes as a surprise to me to see the same tactic employed by conservationists and environmentalists.
When questions are dodged it can mean that the person dodging them doesn’t know the answer, but that is fine, none of us knows all the answers, I certainly don’t. But if that is the case surely it is better to say ‘I don’t know, but that is a good question’ than to try and dodge the whole subject. But dodging it can also mean that they are concerned as to what answering the question will reveal. And that is concerning.
Why wouldn’t anyone who describes themselves as conservationist or environmentalist want to know the answer to the question ‘What is the environmental and carbon cost of large scale tree planting schemes?’.
So, let’s look at what answering that question would entail. I’ll start with the obvious part, the trees themselves. We need to look at where the trees are coming from, Britain imports large numbers of young trees, but we also produce large numbers of home grown trees too (although most of these are conifers such as Sitka Spruce that many wouldn’t consider suitable for these sort of tree planting schemes), so we need to be certain of the exact origins of the trees being planted in large-scale tree-planting schemes. I would hope, and I would like to think, that the trees are from Britain, but just because I hope and think that, it doesn’t mean that this shouldn’t be checked thoroughly. I can’t think why anyone wouldn’t want to ensure this, after all, if the trees for a carbon-offsetting scheme are imported, they come with significant carbon miles on them, so let’s make absolutely sure we know where all the trees in any scheme are coming from.
This needs to be a thorough check though, saying that the trees were purchased from a local tree nursey is not the same as saying the trees originate from a local tree nursery. Tree nurseries buy in stock, sometimes as bare root saplings and sometimes as seeds, so we need to know where these seeds and saplings actually come from. The government say themselves that we import tree seeds from other countries to meet nursery demands and the government also says, and I quote, “As tree planting continues to accelerate, demand for seed and therefore reliance on imports will also increase.”
The Woodland Trust, who are often involved in large scale tree planting schemes, say on their website that all the seeds they use are sourced from the UK and Ireland, which is good, but Ireland isn’t the same country as the UK, it is a different country altogether which means that some of those seeds for these schemes are definitely imported. Yes, trees can be sourced from local nurseries, but to answer the question, ‘What is the environmental and carbon cost of large scale tree planting schemes?’, we need to know exactly where those nurseries are sourcing the seeds from. Of course they might collect the seeds themselves from local sources, in which case brilliant. But if not, we have to factor in the carbon cost of sourcing them into our answer. How many carbon miles have the little seeds travelled to become the trees being planted?
And then we come to growing them, or more precisely we come to the subject of what they are grown in. Looking at the environmental statements of large tree nurseries from across the UK I keep seeing phrases like “reduced peat compost”, “nearly peat free compost” and “working towards being peat free by 2026”. All of that means they are using peat compost. Think about that for a moment, the trees we are planting out this year, the trees that have been planted out over the last decade and more to mitigate the climate crisis have, almost certainly, been grown in peat compost.
Peat extraction is a significant contributor to the release of carbon into the atmosphere, these carbon sinks become carbon sources when we drain and then dig them up. We are extracting peat and releasing tonnes of previously stored carbon into the atmosphere so that we can plant trees out to offset carbon emissions… That doesn’t strike me as being very clever. But it does strike me as emphasising the need to answer the question – ‘What is the environmental and carbon cost of large scale tree planting schemes?‘.
We have known for a very long time what the impacts of peat extraction are, yet the tree nursery growing industry have continued to use it. Yes, the nurseries are now saying they are working towards going peat free in the next few years, but the cynic in me wonders if that is because of impending legislation rather than anything else. The trees in the nurseries today that are still using peat compost, no matter how small the amount, are being grown in peat. These are the trees that will be going into large scale tree planting schemes this year and next year and even the year after that. Schemes that will be marketed as helping the climate crisis.
When I’ve asked about this, I have had the response (it wasn’t an answer), what is the carbon cost of natural regeneration? I don’t know, but I do know it doesn’t, nor has it ever, used peat extraction to happen, so that’s quite a head start on those tree-planting schemes that have used trees grown in peat compost.
By not asking the question about environmental and carbon cost of these schemes, I wonder if the tree-planting industry has actually extended the use of peat as a growing medium for the trees they are using in their schemes, after all if they had asked the question and correctly answered it, wouldn’t they then have exerted pressure on their suppliers to go peat free sooner. But of course, that is just conjecture on my part.
In the future, the nurseries won’t be using peat compost to grow these trees in, but they will be using compost. We need to know what that compost is and how it is produced and manufactured if we are going to truly answer the question. One of the alternatives to peat composts is coir fibre based composts, a product that is touted as being sustainable. It may well be, but we import it from India and Sri Lanka so it comes with significant carbon miles on the clock, again, something else that needs to be included when working out the carbon cost of tree planting schemes.
Aside from what they are grown in, we also need to look at how they are tended whilst in the tree nurseries, are the nurseries certified as being organic, the ones I have looked at certainly don’t say they are. Large tree nurseries are in effect intensively managed crop producing farms, they will use herbicides and pesticides as required, again many of the nurseries say they aim to reduce their use of these chemicals, which is good, but it does mean that they are using them, we need to know what chemicals they are using. There are obviously environmental and carbon costs to using these products, from their manufacture to their application, what are they?
And what about the application of fertilisers? There are significant carbon costs in manufacturing some fertilisers, so any used on the tree nurseries supplying large scale tree planting schemes need to be assessed for that. Are biosolids used? I really hope not, but I don’t know, which is why I am asking rather than just hoping. They are certainly used to fertilise trees in other countries and there has been lots of research published on the benefits they can bring to nurseries, so perhaps they are, I do know that 3,130,000 tonnes of it are used as fertiliser every year in Britain. Biosolids have another name, sewage sludge, see George Monbiot’s recent article in the Guardian Newspaper on them to find out all about the worrying wonders they contain.
That’s a lot of questions about the trees, sorry. But they do need answering if we are to properly answer the question ‘What is the environmental and carbon cost of large scale tree planting schemes?‘. We should always bear in mind that the numbers of trees proposed for such schemes are often in their millions, so as an example, the amount of ‘reduced peat’ compost used to grow one tree needs to be multiplied by the millions too. When you do that, the word reduced doesn’t seem so apt.
Let’s leave the trees.
When you see pictures of large-scale tree-planting schemes, like the photo above of a carbon offsetting planting scheme, you tend to see lots and lots of tree tubes or tree guards. These come with stakes, sometimes incorporated into the guard itself, sometimes not (you can just make out the external ones in the photo). Let’s start with these stakes. The ones in the photo and the majority of the ones you will see in other photos of large-scale tree-planting schemes are wooden. In other words, trees have been felled and their timber used to make stakes to support trees which are being planted. Seems a little ironic really. When millions of trees are being planted there are going to be millions of stakes required.
The stakes are all processed, there is a carbon cost to this processing of course and there is, again, a question of origin. In Britain we import the vast majority of the timber products we use, just over 80% of it comes from abroad, so there is a high likelihood that the timber used to make the stakes is imported. We need to know where it comes from to work out the carbon and environmental cost of doing so. Presuming that the tree-planting scheme managers are only using sustainably sourced timber (most likely FSC rated) this is actually a relatively easy question for them to answer as the timber will be traceable to source. But it is a question often dodged. In response to pointing out the irony of using wooden tree stakes I was told that not all stakes are made from wood. Fair enough, but when I specifically asked what these were made of, I just had more dodge tactics rather than a specific answer. Did they not know or did they not want to say? I’m not sure what you would use instead of wood, plastic or metal perhaps? Whatever it is it will have to be manufactured and it will come with a carbon and environmental cost.
Then, lest we forget, the wooden stakes are tanalised, they are treated with chemicals to stop natural fungal rot and insects from feeding on them, the chemicals used are toxic, they are biocides. They contain copper, a toxic heavy metal, and triazoles, a chemical compound fungicide which is also used as a plant retardant. It is a product that is used to retard the growth of plants, perfect then for putting into the ground next to the roots of the tree it is holding up. There is lots of evidence that demonstrates that the heavy metal and toxic copper from tanalised timber can leach into the soil. It is only in small amounts, but millions of trees need millions of stakes and when you use the factor millions it can make small amounts much larger. There is obvious potential for environmental cost here in the use and production of these chemicals.
And then there’s the tubes themselves, millions and millions of them. Now they were always made from plastic, but new different options are now used and rightly so, but in any scheme, the questions what are the tree tubes made of? Are they completely plastic free? How are they manufactured? What is the source of the products used in their manufacture and where do they originate from? Where are the tubes made? And, what is the environmental and carbon cost of their manufacture? Are all questions that we should be asking if we want to know the answer to my question, ‘What are the environmental and carbon costs of large scale tree planting schemes?’.
I have been told that my question is a tricky one, but in life the trickiest of questions are often the ones that need to be answered the most. Am I being pedantic? Perhaps, but I cannot see how we can say that a large-scale tree-planting scheme is offsetting carbon when we don’t know the exact carbon cost of that scheme. How long will it take for a completed tree-planting scheme to pay off its own carbon cost before it can offset other carbon emissions? Are we talking one year, two years, three years, five years, ten years? I don’t know. The only way we will know is if we address the question properly for all proposed schemes.
I have also been told that I am being negative in asking this question, especially when so many people freely give their time to help the implementation of these schemes. I don’t see it as being a negative action though, I see it as a positive one. Surely those people need to be treated with respect and given the true facts about any potential environmental and carbon costs associated with the scheme that they are giving their time freely to, rather than simple platitudes about them saving the planet. Only by fully answering the question, only by properly auditing everything involved with large scale tree planting schemes can we be positive that what we are doing, and how we are doing it, is indeed the right thing to be doing.
I am sure some people will want to disagree, but before you do, please ask yourself this, do we need to know the true environmental and carbon cost of large-scale tree-planting schemes? If your answer is no, can I ask why?
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You’re right, of course, Ian, to advocate for a full carbon cost assessment of planned large-scale tree planting schemes. One thing that should be considered is that a well-planned planting programme can have carbon sequestration benefits beyond the stand of trees that will result from that planting.
Taking the Carrifran Wildwood project in Scotland as an example, they had to resort to planting because over-grazing had effectively eliminated all of the trees that should have been there, so there was no seed source. But when those planted trees are mature they will become the seed source, and as long as grazing is controlled there should be ample natural regeneration for years to come. It would be very difficult to calculate the carbon benefit to cost ratio for such a project, but I’m sure it would be overwhelmingly positive. The much-cited Rackham doctrine that “mass tree planting is not conservation but an admission that conservation has failed” is a little simplistic, I suggest.
I appreciate the balanced approach you take here—recognizing the value of tree planting while emphasizing the long-term benefits of natural regeneration. In areas where regeneration might be slow due to degraded soil or lack of seed sources, do you see a role for a hybrid approach?
Thank you. This was a blog about the need to know what carbon and environmental costs come with large scale tree planting schemes. I cover the topics of seed sources and land degradation in more detail in my chapter in Great Misconceptions – Rewilding Myths and Misunderstandings. But, briefly, our pioneer tree species distribute their seeds by wind and in huge numbers, Silver Birch for example can produce a million seeds a year and they are tiny and winged and capable of travelling many tens of miles. Acorns from Oaks are distributed by Jays, they have been recorded taking them over 12 miles to ‘plant’ them. So lack of seed source is not really an issue. As for land degradation, in my mind this reads as saying the land is too degraded for trees to grow in naturally, so we will plant trees to grow in it. One minute the land is too degraded for trees to grow in, the next it is ok for them to grow in. I cover this in the book.
Natural succession is exactly that, a succession of stages, each one paving the way for the next.
Apologies, missed this bit off. A hybrid approach could be good, but any planting has to be audited correctly to ensure that carbon costs of the scheme are not high. The trees certainly should not be grown in peat, that is just stupid. The fact that trees are grown in peat, and have been grown in peat, before being used in carbon offsetting schemes beggars belief. It is shameful that this has been happening.
Aren’t the Woodland Trust trialling tree seed spreading by drone? Also I have heard there are special jackets for dogs which release seeds as they wander about. Plus the younger and smaller tree saplings are, the more likely they are to survive. They are also cheaper and therefore more can be planted and some losses can be accepted. If small whips are used, then they would then not need staking. This would also save on stake and labour costs. Of course rabbits, voles and deer can be problematic – more natural predators needed.