- Ground-based laser scanning, called LiDAR, can be used to make detailed maps of forest structure.
- Such detail can allow for more accurate estimates of the amount of carbon stored in aboveground vegetation, which is helpful for assessing the outcomes of reforestation projects and assigning an accurate number of carbon credits.
- Carbon credits, bought and sold on the carbon market, are used by companies and other entities to offset their own greenhouse gas emissions.
- But experts caution that transparency, not estimation accuracy, remains the carbon market’s biggest challenge.
Forests are natural carbon sinks. But as reforestation of degraded land is becoming a global climate solution, a persistent question lingers: How do we know how much carbon a forest is actually storing?
Researchers say ground-based laser scanning, or LiDAR, could improve the efficiency of measuring the outcomes of reforestation. And a recent paper published in Ecological Solutions and Evidence found that LiDAR scanning in Australia offered an improvement over other methods of carbon estimation.
LiDAR instruments emit thousands of tiny laser pulses to create complex and intricate 3D maps of a forest’ structure, allowing researchers to more accurately estimate how much carbon is contained in its trees. Co-author of the paper Alexander W. Cheesman, a senior research fellow at James Cook University, North Queensland, Australia, calls the technology “transformative.”
“Traditional field surveys heavily relied on manually measuring the height and diameter of a relatively small number of trees. But laser scanning captures the whole forest in 360 degrees, recording every stem, every branch and the shape of the canopy,” Cheesman told Mongabay during a virtual interview over Google Meet.
In Australia, the Full Carbon Accounting Model (FullCAM) is the government’s main tool to track carbon stored in soil and roots (belowground carbon) and vegetation (aboveground carbon). It is used for national greenhouse gas reporting to the United Nations and to assess carbon credit within the country, through the government’s Australian Carbon Credit Unit (ACCU) Scheme. Rather than directly measuring carbon, FullCAM simulates the movement of carbon through ecosystems by integrating data on climate, soils, land use and management and land cover change.
In their study, Cheesman and his coauthors compared carbon estimates produced by Australia’s FullCAM model with LiDAR measurements for three restored rainforest sites established in the 1990s.
The researchers found that the FullCAM model estimated the test forests contained 8% less carbon than LiDAR. While they acknowledge that 8% isn’t a dramatic difference and that “the model performed reasonably well,” they maintain that LiDAR still offers an improvement.
However, other experts say that LiDAR is not free from errors, and that it is a very expensive tool. Some entry-level terrestrial laser scanning equipment costs more than $40,000, making it unaffordable for projects without adequate funding. Moreover, the paper’s conflict of interest statement discloses that co-author Abbey R Yatsko, is an employee of ArborMeta, an Australian LiDAR-based forest monitoring company.
Andrew Macintosh, a professor of environmental law and policy at the Centre for Environmental Markets at Australian National University, Canberra, said LiDAR is already considered a useful tool to estimate aboveground biomass, and the study largely reiterates an established point.
The larger question for Macintosh is: Can improving accuracy of biomass measurement really improve the integrity of the markets where carbon credits from tree-planting projects are bought and sold? Cheesman believes it can, saying that the higher accuracy of LiDAR’s aboveground carbon estimates will enhance trust in restoration outcomes, resulting in higher fund allocation for reforestation projects in the future.
Australia has two types of these “carbon markets:” compliance, which is required by governments, and voluntary, where individuals and organizations can issue, buy or sell their carbon credits. For instance, a company looking to offset its greenhouse gas emissions can fund a reforestation project that captures and stores an equivalent amount of carbon from the atmosphere.
But carbon markets have come under increased scrutiny in recent years, with experts questioning whether projects deliver the climate benefits they claim. Accuracy of carbon offsets and auditing methods, transparency of project data, and the ability of independent researchers to verify the results continue to dominate debates around carbon markets.
At the same time, reforestation projects are attracting the attention of companies looking for ways to meet net-zero emissions goals through nature-based climate solutions.
UN data suggest that investment in restoration needs to quadruple to $296 billion by 2030 to meet global restoration targets while contributing to climate and biodiversity goals.
Macintosh said that despite this, tree-planting projects garner a relatively small share of issued carbon credits. In Australia, these projects accounted for about 1% of issued credits in the fiscal year 2022-2023.
“For reforestation/afforestation projects, the biggest issue is transparency,” Macintosh said in an email.
He pointed out that the projects included in the LiDAR study did not publish the offset or audit reports of the model sites. He said many carbon projects do not make enough information publicly available for outside researchers to assess whether the issued carbon credits accurately reflect how much carbon is captured and stored in a restored forest.
Cheesman agreed that technology is only one part of the solution, and said that wider adoption of ground-based LiDAR will depend on whether the technology becomes more affordable and accessible to restoration projects. However, he added that ground-based LiDAR could also be useful beyond carbon accounting; it could also be used to capture detailed information about forest structure including canopy layering, foliage density and habitat complexity.
“These characteristics can be used to assess biodiversity and ecosystem recovery,” he said, adding such data could provide a more comprehensive picture of restoration success.
Banner image: Two images captured by LiDAR at different times and overlaid: one of young tree seedlings (pink), the other of the same trees (blue) after two years of growth. Image courtesy of ArborMeta.
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Citations:
Cheesman, A.W., Cernusak, L.A., Yatsko, A.R., Calvert, J., Cook, K. (2026) The role of ground-based laser scanning in quantifying and crediting tropical forest restoration: An Australian case study. Ecological Solutions and Evidence, 7(1). e70213. doi:10.1002/2688-8319.70213
Eitel, J. U., Vierling, L. A., Magney, T. S. (2013) A lightweight, low cost autonomously operating terrestrial laser scanner for quantifying and monitoring ecosystem structural dynamics. Agriculture and Forest Meteorology, 180, 86-96. doi:10.1016/j.agrformet.2013.05.012
Sasaki, N. (2025). Addressing scandals and greenwashing in carbon offset markets: A framework for reform. Global Transitions, 7, 375-382. doi:10.1016/j.glt.2025.06.003
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Cite this article
Shradha Triveni (2026). Laser scanning forests may boost carbon estimates, but credibility questions linger. Mongabay Conservation news. DOI: https://doi.org/10.66709/news-321918Credits
