Most measurements for carbon storage mainly considers trees above 10 centimeters in diameter and are not fit to quantify carbon in young restoration forests (photo: regenerated Atlantic Forest area in an old eucalyptus plantation/Paulo Molin)
Published on 12/03/2025
By Karina Toledo | Agência FAPESP – Brazil could become a major player in the global carbon credit market, as important as Saudi Arabia was for oil in the 20th century. However, to exploit this wealth, it will be necessary to invest in technology and develop new, improved strategies for quantifying the carbon being traded.
This analysis was presented by Pedro Brancalion of the University of São Paulo (USP) during the FAPESP Day Uruguay symposium in November in Montevideo.
In his presentation, Brancalion presented the results of projects that seek to leverage the carbon credit market in Brazil. One of these projects resulted in a new equation for estimating above-ground biomass, which increases the carbon credits generated in Atlantic Forest restoration processes by 30%.
“Imagine a company that raises cattle to produce meat. Suddenly, we introduce a revolutionary technology that increases meat production by 30% without spending an extra cent. It’s almost a miracle. That’s what we’re providing for the carbon restoration sector. Not because we’re stealing, but because we’re quantifying better,” he said.
This and other topics were discussed in an interview with Agência FAPESP during the event. See the main excerpts below.
Agência FAPESP – In your presentation during the FAPESP Day Uruguay event, you mentioned a new equation for estimating above-ground biomass that increases the carbon credits generated in forest restoration processes in the Atlantic Forest by 30%. Could you explain how this equation was developed and how it works?
Pedro Brancalion – We analyzed data from a restoration plantation that’s now 22 years old and is our great laboratory. It’s measured every year. When this experiment was implemented, we predicted that some parts of the forest would be cut down for research purposes. We cut down 180 trees when the plantation was six years old, then again when it was 12 and 20 years old. In this way, we were able to generate an equation to understand how much carbon is stored in that forest. Today, the most widely used equation [to evaluate restoration processes and generate carbon credits] is the one developed by French researcher Jérôme Chave, who synthesized destructive sampling in tropical regions. However, the database he used mainly considers trees above 10 centimeters in diameter. Our method, on the other hand, includes those above 5 centimeters in diameter, as there’s a lot of carbon in smaller trees in young forests. There’s nothing wrong with Chave’s method, but it was designed for mature forests in the Amazon, Congo, and Asia – not to quantify carbon in young restoration forests in the Atlantic Forest. And why did people use Chave’s equation? Because there was no better one. So with this research, we’re filling a knowledge gap that’s fundamental to leveraging a new market. This work was done by a doctoral student, Ana Paula Ferez, and is linked to one of the projects of the RCGI [Research Center for Greenhouse Gas Innovation]], supported by FAPESP and Shell.
Agência FAPESP – And does the equation only take into account the tree trunks?
Brancalion – No. We count the roots, trunks, thick branches, thin branches, and leaves. We use a chainsaw to cut the tree into these parts, remove all the leaves, and weigh them. We send them to the lab to analyze the dry mass. Then the tractor comes in, digs up the soil, removes the thick roots as best it can, and cleans up. We put everything on a giant scale. So, literally, we weigh the forest. This was done to construct the equation and also to develop strategies for measuring carbon using LIDAR [Light Detection and Ranging, a method that uses drones emitting laser pulses to measure the structure of vegetation]. LIDAR measures the average height of the canopy and, based on that data, estimates the biomass using specific equations. But it’s an estimate. What we’re trying to do is connect the information obtained from destructive sampling directly with LIDAR measurement.
Agência FAPESP – How can these technologies help leverage the carbon credit market in Brazil?
Brancalion – No one will buy carbon credits if there’s doubt about the amount being traded. Any market needs a robust basis for quantifying what’s being sold or bought in order to develop. In uncertainty, in risk, no one plays. So, imagine a company that raises cattle to produce meat. Suddenly, we introduce a revolutionary technology that increases meat production by 30% without spending an extra cent. It’s almost a miracle. That’s what we’re providing for the carbon restoration sector. Not because we’re stealing, but because we’re quantifying better. An analogy I make is that Brazil is to this market what Saudi Arabia was to the oil market in the 20th century. Brazil could be the world’s largest negative carbon sink. It has vast tracts of land, super-productive forests, and technology, things that many other countries don’t have. Continuing the analogy with oil, I often say that this carbon isn’t in a shallow well, easy to exploit, as in the case of Saudi Arabia. It’s more like pre-salt oil. The wealth is there, but we can only access it with technology. That’s the challenge of restoration today. There’s great potential, but for that potential to manifest itself and for us to be able to supply the international market with this additional product from our lands, we need technology.
Agência FAPESP – You mentioned another experiment aimed at improving carbon measurement in forests, the flux tower. Could you explain what it is?
Brancalion – That’s another project, also supported by FAPESP. It’s being conducted in Itatinga, at a USP experimental station. What’s the premise? Carbon fluxes in a forest occur every second. It’s a bird decomposing, a microorganism eating a leaf, a blade of grass absorbing light and photosynthesizing. It’s something dynamic, which varies over the years, for example, depending on whether or not there’s El Niño. The most advanced technologies today provide a rather rough quantification. It isn’t a magnifying glass on what’s actually happening. Due to technological limitations, we’re unable to measure these details. The flux tower also doesn’t see who’s emitting or absorbing carbon, but it does see the balance. So, it’s the litmus test. With it, we can know the net effect of that restoration as a carbon sink. And then we’re not just looking at the branch or the trunk, but at the entire ecosystem, including the soil. A tower like this allows us to understand mechanisms. For example, how much this balance is impacted in a drier year or by a rainy event. It’s a very powerful scientific tool, although expensive and complicated to use.
Brancalion: The main challenge today in forest restoration is to develop the technology needed to scientifically quantify the amount of CO2 being traded, thus meeting international market demands (photo: Karina Toledo/Agência FAPESP)
Agência FAPESP – The NEWFOR Thematic Project, which you coordinated, recently ended. Tell us a little about the results and how they relate to these other initiatives.
Brancalion – They are, in a way, developments. Our goal with NEWFOR was to build the world’s largest database on tropical reforestation. Research on restoration and reforestation lacked strong databases. Previous studies had a very low sampling effort, focused on one or another reforestation method, and didn’t cover large areas, so they couldn’t adequately represent the enormous heterogeneity of tropical forests. With this database, we can explore scientific questions that were already being explored in a much more robust way and, at the same time, establish a basis for future research. We can use that data to leverage other more ambitious projects.
Agência FAPESP – And how was this database built?
Brancalion – We defined eight land cover types of interest, on a gradient ranging from agricultural land use [pasture and agriculture] to two reference systems: degraded and conserved forest remnants. Five reforestation systems were also included: agroforestry, active monocultures [such as eucalyptus for pulp production]; extensive monocultures [such as those used for lumber production, where there’s a lot of natural regeneration in the understory]; restoration plantations [where several native species are mixed]; and forests established by natural regeneration [spontaneously, from the isolation of the area after agricultural use]. We then applied a protocol to assess the multifunctionality of the forest in 30-by-30-meter plots. More than 800 plots were established throughout the Atlantic Forest, in which we analyzed biodiversity, carbon stored in all forest compartments, such as soil, fine and coarse roots, living woody biomass above ground, standing and fallen dead wood, vines and litter, as well as water infiltration into the soil and many other things. Each tree was measured in these plots, totaling about 70,000 trees of approximately 1,300 different species. To this end, we established partnerships with NGOs, companies, governments, rural landowners, and various conservation units through a process of knowledge co-production. These people were engaged to answer the project’s big research question, which has already yielded 40 scientific articles, all in international periodicals, in high-level journals. But the main legacy I see from this project is that it’ll serve as a basis for several others. Someone interested in studying birds and restoration, for example, can make use of these permanent plots we’ve established, with all the trees identified. Or they can use LIDAR to assess the structure. So I joke that we’ve created a scientific amusement park.
Agência FAPESP – You mentioned the project’s big scientific question. What is it?
Brancalion – It’s this: How are different types of environmental benefits generated by different reforestation methods in different environmental conditions? That question is critical for those who invest in reforestation for a specific purpose, whether as a business or to generate collective benefits from public or philanthropic funding. Knowing how much carbon I can sequester, for example, in a given region, depending on the reforestation method, is the basis of any investment model. In addition, it’s important to know how other benefits are associated, such as carbon and biodiversity, so that projects can be designed and established. Our results thus allow us to maximize the cost-benefit of reforestation, expanding the multiple benefits per unit of investment, supporting new businesses, public policies, and conservation actions.
Source: https://agencia.fapesp.br/56669
