Concerned That We Are Overestimating the Potential of Forests

During the Finding CCL's Next Climate Policies Saturday Seminar, Tony and Dana set the criteria that CCL's new policy initiatives should have a large enough scope to meet the challenge of climate change and our mission as an organization. After digging through some of the peer-reviewed literature on natural climate solutions, I am worried that forests don't meet this criteria.

The Community training on this topic points out that 10 Gt C / yr of emissions will be difficult to abate from the global economy. Of that, the training claims that 1 Gt C / yr could be sequestered by U.S. forests. This is a great target in principle, and the additional co-benefits from planting trees should make this a popular policy across the political spectrum.

However, I am worried that we aren't considering how hard it is to get to 1 Gt C / yr. The National Academy of Science report that CCL cites puts an upper limit on annual sequestration from reforestation/afforestation and improved forest management at 0.6 Gt C / yr. This number, they say, is “highly unlikely because of the following constraints: the availability of land for conversion from current uses, leakage and risk of reversal from disturbances, and economic and behavioral barriers to full adoption on all available land.” They believe more realistic number is 0.25 Gt C / yr.

The Fargione et al. paper that the training cites also puts the number at around 0.6 Gt C / yr, but again this requires a) reforesting all historically forested land not under use for development or agriculture and b) extending harvest cycles in all managed forests. 100% adoption here feels like it will be incredibly difficult to achieve given the constraints that the National Academy report lists.

Finally, I worry about the permanence of forests as carbon sinks. Even if forests stay healthy, they mostly act as temporary stocks of carbon, not as ongoing sinks. As the figure below from the USDA illustrates, most forest biomass eventually reenters the atmosphere. Even if it is harvested as lumber, it will eventually end up decomposing in a landfill. About 0.7% of productivity gets permanently sequestered by soils, but even this modest carbon sink is weakening as the atmosphere warms. For perspective, all established temperate forests (which is what we mostly have in the U.S.) around the world permanently sequester only 0.72 Gt C / yr. The upshot of this is that the reforestation sequestration numbers we are working with are only temporary; once a new forest has matured, it will remove less and less carbon from the atmosphere. The 1 Gt C / yr that we are targeting--even if we get there--won't be a permanent solution to mitigate our difficult-to-abate emissions.


So, the practical challenges to reforesting the entire country and improving the management of all working forests across the U.S. are massive. Further, even assuming that policy can achieve these monumental changes in U.S. forest management, we are only looking at a few decades of sequestration before new forests are largely matured and lumber winds up decomposing in a landfill. CCL has taught us not to look for silver bullets, so maybe even modest improvements in forest management are worth pursuing. Still, I worry that putting forestry front and center opens us up to criticism of greenwashing, especially given the challenges I have laid out and the high profile media pieces criticizing forests as a climate solution.

I am writing this forum post to raise my concerns about this strategy given my academic experience studying ecosystem ecology. However, I welcome other people's thoughts on this, especially given that this is a complex topic from both the science and policy perspective. Would framing forests as a temporary solution for carbon sequestration be enough for us to justify our support? Are there other areas of land management, like improved agricultural practices, that we could consider in tandem with forests as a suite of natural climate solutions that get us closer to 1 Gt C / yr in perpetuity? Could we look at U.S. trade policies that encourage other countries to replant their tropical forests (like what we are doing with the FOREST Act), which have a much higher potential to sequester carbon?

20 Replies

Hi Elliott.  Thanks for providing your thoughts on this issue.  We have certainly shared many of them during our research and decision process, and I would encourage you to check out our Forests Training Page, where some of them are addressed.  Permanence is certainly a challenge, but US forests currently sequester about 800 billion tons (Gt) of CO2 per year, and boosting that by ~200 Gt in the near term seems feasible as long as we encourage smart forestry practices through good policy.

Regarding whether that's sufficiently large to merit CCL support, one big challenge we faced in evaluating possible future policy objectives is that aside from carbon pricing, there really aren't any huge individual climate policies.  Solving the climate problem will have to involve a lot of solutions that reduce emissions by small chunks, and forestry is one of those.  Agriculture also has potential, and falls under the category of natural climate solutions that we may yet still pursue.  ‘Building the clean energy economy’ is another broad category, under which we haven't yet decided on specific policies.  Forestry is just our first additional focus, but it's an important one.  I'll have more to say on the size of the solution in a post about some relevant new research on the CCL blog, likely next week.

Kevin Mulvey
101 Posts

@Dana Nuccitelli I share the concern expressed by others about 1) the diffusion of focus away from CF/D and 2) the over-selling of reforestation as a solution to climate change.  I raise these concerns as someone who has been a volunteer tree planter for the past decade, and worries about CCL's shift to a broader set of less-impactful set of solutions.  

I'd be interested to know whether the statement in this July 13 NY Times piece is correct ("the world continues to lose trees at a far faster rate than it gains them") , and whether this previous research remains largely valid ("Furthermore, they concluded something like 15 billion trees were still being cleared each year, for a net loss of about 10 billion trees annually")?   

If CCL is going to speak about the value of forests, I'd prefer to see a greater emphasis on preserving and protecting existing forests, from wildfires and deforestation, rather than the quixotic notions of planting a gazillion saplings, which frankly is an easy out for a lot of folks who refuse to admit the inconvenient reality of climate change, but see the political benefit of seeming to care.. 


Kevin Mulvey
101 Posts


Jeff Green
42 Posts

Elliot raises hard to dismiss points regarding CCL’s new focus on “Trees and Forests as Natural Climate Solutions,” and the NYT article cited by Kevin zeroes in on multiple potential issues with supporting policies of reforestation and afforestation:

  • “An even bigger challenge in trying to judge the collective achievements of the global tree-planting campaigns stems from the fact that people are not really planting trees, which offer a host of benefits and are famously tough, capable of surviving for hundreds or sometimes thousands of years and of weathering all kinds of trials and insults. They are planting seeds or seedlings, which offer few benefits and are not tough at all.”
  • “John Lotspeich, the executive director of Trillion Trees, the collaboration between the World Wildlife Fund, the Wildlife Conservation Society and BirdLife International, told me that its goal is to protect existing forests, address the root causes of deforestation and restore degraded landscapes. While that may include planting some trees, he says, ‘our three organizations have not been about finding a free field somewhere and putting some trees there.’”

CCL must avoid falling into the traps of counting seedlings as trees and of promoting “private working forests” that are, in reality, “green deserts” totally lacking in biodiversity (see, e.g. “Forest Plantations Do NOT Create the Natural Forest Ecosystems We Need.”

However, CCL has a great opportunity in the area of “tree equity,” i.e., lobbying for increasing the tree cover in EJ communities.  It’s in these urban areas where increasing tree cover could provide substantial benefits in lowering ambient temperatures and providing sorely needed employment opportunities.  CCL could be instrumental in monitoring tree-planting programs to ensure that the trees are cared for by members of the affected communities (long term employment) and, thus, survive to reach a size where they become effective carbon sinks and providers of shade.

If CCL is searching for meaningful areas in which to expand, then US agriculture is another area that’s ripe for reform. We have a system that uses huge amounts of arable land to grow corn and soybeans that are fed to cattle and hogs  confined in massive feedlots (CAFOs, in industry parlance) excreting immense lakes of methane-producing liquified manure; our government needs our help with this problem (“New Report Says Plans to Reduce Methane Fall Short on Big Meat and Dairy.”  We end up with an artery-clogging diet of red meat and the deforestation of the Amazon.  Who benefits from this system? (maybe the folks who support the GCSA, but that’s another discussion 😄 )

Our agricultural practices are destroying biodiversity and the soil through the over-application of nitrogen fertilizers, herbicides, and pesticides; petrochemical inputs whose use benefits our friends in the fossil fuel industry.  The dirt that’s leftover after this chemical stew is applied sequesters nothing but poison.  If CCL is looking for “huge individual climate policies,” let’s start with what’s on our dinner plate.

Hi Kevin and Jeff, thanks for the comments and questions.  Many have been addressed in the Forests Training Page and the Forests CCU I gave last week, so I'd recommend starting there. 

Forest issues and solutions differ by region. Deforestation is a big problem globally, but mostly in countries like Brazil and Indonesia (the FOREST Act aims to curb that problem to some degree).  It's not a problem in the US, where we're pretty good at practicing sustainable forestry on the whole, which is why the amount of carbon removed by US forests has remained steady over the past few decades. Forest conservation is certainly important, but so is reforestation (planting trees where they used to be present). That's done with seedlings, but it's much easier to monitor and ensure their growth domestically than internationally. Those seedlings need to be of diverse and appropriate species, as I discussed in the CCU.

We feel that CCL has grown to a point where we can expand our advocacy to a few other areas without diluting our support for carbon pricing. And as we've noted, one of those areas is natural climate solutions starting with forests, which may eventually expand to include agricultural solutions as well. I'll also just note that we're making a conscious effort not to oversell natural solutions, but they nevertheless are very important, as I discussed in the CCU.

If you have any further questions, don't hesitate to ask.  Also feel free to visit us at the Nerd Corner for wonky discussions!

Jeff Green
42 Posts

@Dana Nuccitelli I've reviewed both the training page and your video presentation, and  we agree on the necessity for a type of reforestation that doesn't create monoculture green deserts that benefit only timber companies.  Your emphasis on urban reforestation is also absolutely in line with my thinking.  I found your mention of Brazil and Indonesia as problematic countries with regards to deforestation as, also, spot on.  However, we need to keep in mind that deforestation in those countries is being driven to a large extent by, in the case of Brazil, US beef imports, and, in the case of Indonesia, by the US (and other wealthy countries) appetite for palm oil. 


Thanks @Jeff Green. Indeed, that's why CCL supports the FOREST Act, which takes steps to restrict goods originating from illegally deforested land. We have limited leverage over deforestation in other countries, so it's a smart bill to take advantage of our consumer leverage there!

Kevin Mulvey
101 Posts
Dana et al -  I feel very strongly that if CCL is going to lend it's good name and lobbying muscle to selective tree and forest proposals, we should focus primarily on protecting existing carbon sinks, rather than be supportive of new plantings.  The math simply can't work if we keep losing mature forests and attempt to replace them with saplings.

These maps show how alarmingly fast California is losing trees as climate warms

Hi @Kevin Mulvey.  I'd recommend this paper on the subject, whose Figure 1 in particular (reproduced below) illustrates how much more climate mitigation potential there is from reforestation and forest management than from avoided forest conversion, which not a big problem in the US.  In fact as I've noted, our overall annual natural carbon removal has been steady over the past ~20 years.

California is of course a special specific case, and the paper does highlight the potential mitigation from fire management, which is a small component of the forest management category. And as I've discussed, climate-smart forestry in California is important – doing things like thinning, prescribed fires, etc.  But from big picture perspective, the largest gains to be had in domestic forestry policy are from reforestation and forest management.

Figure 1 from Fargione et al. (2018)
Ben Fritz
5 Posts

@Dana Nuccitelli

We feel that CCL has grown to a point where we can expand our advocacy to a few other areas without diluting our support for carbon pricing. And as we've noted, one of those areas is natural climate solutions starting with forests, which may eventually expand to include agricultural solutions as well. I'll also just note that we're making a conscious effort not to oversell natural solutions, but they nevertheless are very important, as I discussed in the CCU.

First, Dana, I just wanted to point out that you made it very clear that this will not dilute CCL's focus / oversell the importance in the training!

I also wanted to share that I'm a good example of why this doesn't have to be the case…

I am new to CCL (and therefore not heavily involved in any given area of action just yet) and was very excited to hear about the “trees & forests as natural solutions” addition. Nature is where my personal passion is rooted (no pun intended), so while I'm definitely here to support climate change in general, an area like this that can help move that needle while conserving our beautiful earth - I can really get into that.

All that to say, there may be many folks like me who get more involved in CCL than before, rather than this spreading out the focus of folks already doing great work with the existing structure and CF&D.

Also, I wanted to add that I'm excited about the possibility of other nature-based solutions (i.e. agriculture) being added in the future. The folks at Kiss the Ground are doing great work with their Regenerate America movement.

As a final thought…

I believe that it's actually possible to underestimate the impact that natural solutions can have because of how complex earth's systems are. We are limited to what we can quantify (although I acknowledge the importance of that in policy in particular.) Additionally, it would follow that supporting many natural solutions (by humanity in general, not just CCL) would have a compounding effect.

Again, these impacts aren't meant to be relative to CCL's main focus, just some general thoughts. I appreciate all of the thoughtful discussion here!

Thanks, @Ben Fritz. It's certainly possible that we'll expand to include agriculture among our supported natural solutions.  Cover cropping in particular has good potential to store more carbon in soils with a lot of co-benefits.  The challenge is just in providing farmers sufficient incentive to adopt the practice.  But at the moment we're focusing on how to maximize the potential of forests, with silvopasture (planting trees on pasture land) looking especially promising, but urban trees also having significant potential and co-benefits.

Kevin Mulvey
101 Posts

@Dana Nuccitelli  Thanks Dana, I appreciate the info.  California, and increasingly the wider north west and mountain west, are losing vast stretches of forest to drought, beetles, fire ect, and can be expected to continue to do so for the foreseeable future.  Are you saying we can replace these massive carbon losses in a net-postive way through new plantings, in any kind of reasonable time frame? 

Hi @Kevin Mulvey.  It's going to require a combination of climate-smart forestry practices to slow the rapid growth of wildfires, and then some replanting of burned areas using methods to make them less susceptible to future fires.  We'll see how successful we are in applying those approaches.  Hopefully we can at least prevent California forests from remaining a net carbon source rather than a sink.

Kevin Mulvey
101 Posts

@Dana Nuccitelli an additional resource for anyone interested in this topic.. 


@Dana Nuccitelli
The thread concerning agriculture as a possible area of interest for CCL's policy agenda seems to have gone more or less dormant, but I wanted to inject one more point in favor of moving on agriculture sooner rather than later.

I don't want to take anything away from the importance of forestry as an important solution, but 2023 is a Farm Bill year, so it might be of strategic value to lean in on agriculture this coming year. Most of the things that CCLer's are talking up as ag-centered solutions fall under a few of the titles of the Farm Bill, and funding levels/rules will be hashed out in the coming months.

If it feels like this is stretching CCL's staff and expertise too thin, there are lots of potential partner organizations who have done a lot of thinking and research on these topics, but who may not have CCL's reach as a grass-roots lobbying organization.

So, all I'm saying is that maybe the timing of strategic focus points deserves a second look.

Hi @Matthew Mayers.  We'll definitely be working to try and get some climate solutions into the 2023 Farm Bill.  One avenue is through various conservation programs like EQIP, which the IRA provided over $20 billion dollars to under the guise of ‘climate-smart’ natural solutions.  But those programs don't include climate or carbon as a criteria for the projects that are selected for grant funding.  So, one possibility is that we could try to modify those programs through the Farm Bill to include climate/carbon as a selection criterion, which would help direct those funds to both forest and farm natural climate solutions like silvopasture and cover cropping.  We'll see if that's a possibility in the next Congress, though we're focused on healthy forests because they're already established as a natural climate solution, whereas agricultural solutions are still in the growing phases (no pun intended).

@Dana Nuccitelli, thanks for your reply. I'm glad to hear there is some interest in improving the Farm Bill.

As you probably know, the Agriculture Resilience Act proposes a lot of language to promote beneficial climate effects in the allocation of conservation title funds, but it has the problem of being very partisan and being perceived as out of the mainstream and too much in line with what is being called regenerative agriculture. Some MOCs and some farmers don't like this language and may even find it insulting.

However, as a general rule, the same practices that climate people like about regen ag also do things that lots of farmers and their political representatives can get behind--increase soil health and water retention, reduce input costs and drive up farmer profits, boost resiliency in the face of severe weather events.

If there were a way to tweak the language of Pingree's proposals to focus on those on-farm outcomes and terminology that is more attractive to conservative MOCs, maybe we'd have a chance of seeing progress on this front.

@Dana Nuccitelli, sorry to keep bugging you on this point. I learned something last night that might be of interest to CCL's national leadership team, namely that USDA is taking public comments until Dec. 21 on how we think they should use the extra billions that the IRA directed to them. Apologies if you already knew that. I'm just wondering if CCL national is planning to submit a comment. So far there are very few comments in the register and most are not very helpful. Possibly we could make a difference here with a relatively small amount of effort.

Here's the link to the relevant Federal Register page:

As a last note, I want to thank you for all the great communication you do for CCL members. I always look forward to your posts, talks, etc. I'm positive that others feel the same.

Thanks for flagging that, @Matthew Mayers. That's interesting and I'll look into it.

Jeff Green
42 Posts

@Matthew Mayers @Dana Nuccitelli

Great point Dana!  I belong to the Chicago chapter of the Climate Reality Project, and we have a regenerative ag team that's analyzing the Farm Bill and is working with other CRP chapters on RA issues.  I'd be happy to hook that team up with the appropriate CCL resources.

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