The team’s fieldwork covered 16 plots across four land-use systems, each plot a 500-square-meter sampling unit designed to capture the internal variability of these ecosystems. In the coffee systems, located between 1,060 and 1,080 meters above sea level, the researchers measured every tree within their plots, recording trunk diameter at breast height, total height, and wood density. These measurements fed into generalized allometric regression equations that estimate aboveground biomass from trunk dimensions and wood basal density, with species-level wood density values drawn from the Global Wood Density Database. Where species data were unavailable, the team used genus or family averages. Belowground biomass was estimated using root-to-shoot ratios developed for tropical highland forests, and a standard carbon fraction of 50 percent was applied to convert dry biomass into carbon, a figure consistent with IPCC default values of 0.47 to 0.50 for tropical woods.

The results are unambiguous. Primary forests stored approximately 133.74 tonnes of aboveground carbon per hectare and 40.12 tonnes of belowground carbon per hectare, equivalent to roughly 638.05 tonnes of carbon dioxide per hectare when the carbon is converted to its CO2 equivalent. The coffee systems, by comparison, stored dramatically less. Among them, the agroforestry coffee system with mixed shade trees performed best, followed by coffee grown with Inga, while the monoculture system consistently registered the lowest values across every carbon metric. The statistical models, fitted with Gamma distributions and generalized linear mixed models in R, achieved adjusted R-squared values exceeding 99 percent, confirming that the differences in carbon storage were overwhelmingly associated with the type of ecosystem rather than random variation.

Biodiversity followed the same gradient. Using the Shannon index, Simpson index, and Pielou evenness index, the researchers found that primary forests hosted the highest species richness and the most balanced distribution of individuals across all metrics, with statistically significant differences at p < 0.01. The agroforestry coffee system maintained a species richness of 6.25, though its lower evenness value of 0.42 suggested that a few dominant species shaped the community. Coffee grown with Inga showed lower richness at 2.0 but moderate evenness at 0.58, while the monoculture system presented minimal diversity, reflecting a simplified community dominated by very few species. The primary forest’s superior diversity may be linked to its higher elevation of 1,625 meters, where cooler temperatures and greater humidity favor the coexistence of more plant species.

When the researchers translated carbon storage into economic terms using Peru’s social cost of carbon of 7.1 US dollars per tonne, the primary forest’s value reached approximately 949.52 dollars per hectare in aboveground carbon alone, with additional valuations of 284.86 dollars per hectare in belowground carbon and 4,530.15 dollars per hectare when total CO2 storage was considered. The coffee systems, by contrast, registered values far below these figures, with the agroforestry system performing best among them and the monoculture worst. The economic gap between primary forest and any coffee system is so wide that the researchers describe forest conversion as generating significant losses in carbon-related benefits, losses that compound with every additional hectare cleared.

A sensitivity analysis tested how these valuations would shift under alternative carbon pricing scenarios. At low prices of 5 and 20 dollars per tonne of CO2, the economic differences between coffee systems narrowed considerably. But from 50 dollars per tonne upward, the gap widened, with the agroforestry coffee system standing out as the highest-value option among the coffee treatments, followed by coffee with Inga and then the monoculture. At 100 dollars per tonne, the greater structural complexity of the agroforestry system translated into a clearly visible relative economic advantage, suggesting that carbon markets could increasingly reward farmers who maintain shade trees and diverse canopy structures within their coffee plantations.

A principal component analysis integrating the ecological and economic data revealed that the first two axes explained 94.07 percent of total variation, with the first component capturing a robust gradient from simplified monoculture systems to complex, carbon-rich primary forests. The biplot positioned primary forests at the high end of total CO2, evenness, Shannon diversity, and Simpson index values, while the agroforestry coffee system clustered near species richness, and the monoculture sat at the opposite end of the gradient. Coffee with Inga occupied an intermediate position, suggesting a transitional state between low and high ecological complexity. This multivariate structure reinforces the biodiversity-functioning theory: ecosystems with greater species diversity tend to store more carbon because diverse communities use resources more complementarily, build more complex forest structures, and are more resilient to environmental disturbances.

The findings carry direct implications for climate policy in Peru and beyond. The researchers note that forests are expected to contribute roughly 10 percent of the mitigation required to limit global warming to 1.5 degrees Celsius, which would require carbon prices to reach approximately 281 dollars per tonne of CO2 by 2055. By comparison, the average carbon sequestration cost in northwest China has been estimated at 4.77 dollars per tonne, well below the 7.1 dollars per tonne applied in this study. Protecting forests in the Peruvian Amazon may require investments ranging from 7.97 to 10.45 dollars per tonne of CO2, figures that support the implementation of conservation strategies and increase the economic value of standing forests. The study’s authors argue that these valuations provide a technical basis for incorporating coffee agroforestry systems into Payments for Ecosystem Services schemes and for aligning coffee production models with Peru’s Nationally Determined Contributions under international climate agreements.

The research also speaks to the principles of REDD+ initiatives, which aim to conserve forests and increase carbon stocks through economic incentives. The observed transition from monoculture coffee to agroforestry systems represents a trajectory compatible with REDD+ objectives by simultaneously increasing stored carbon and biological diversity. The economic potential associated with conserving tree cover, rising from 174.06 dollars per hectare in monoculture to 4,530.15 dollars per hectare in primary forest, illustrates how market mechanisms such as PES and REDD+ can generate effective incentives when supported by strong institutions, transparent monitoring systems, and equitable distribution of benefits among local actors. In Latin America, which constitutes one of the main global suppliers of forest carbon credits, agroforestry systems hold particular promise for generating credits due to their CO2 capture capacity, though certification continues to face challenges related to additionality, permanence, and transparency of projects.

The authors acknowledge that their observational comparison carries limitations. The primary forest site sat more than 500 meters higher than the coffee systems, an altitudinal difference that could influence carbon dynamics, though previous research has shown that the loss of aboveground biomass from forest conversion dominates the carbon balance at all elevational levels. The models achieved high statistical fit, but uncertainty remains associated with ecosystem variability, biomass measurement, and the selection of allometric equations, meaning small changes in carbon estimates could modify the economic valuation of the ecosystem service. Nevertheless, the study’s central message is clear: conserving native forests remains the most effective strategy for maintaining carbon storage, biodiversity, and ecosystem services in the Peruvian Amazon, while promoting sustainable agroforestry practices offers a complementary pathway that rewards farmers for keeping trees on the land. As Peru grapples with continued forest loss, these findings provide the quantitative evidence needed to make standing forests economically competitive with the coffee that threatens to replace them.

Subject of Research: Carbon sequestration economics of forest-to-coffee conversion in the Peruvian Amazon

Article Title: Converting forests to coffee cultivation (Coffea arabica) significantly reduces organic carbon sequestration payments in the Peruvian Amazon

Article References: Converting forests to coffee cultivation (Coffea arabica) significantly reduces organic carbon sequestration payments in the Peruvian Amazon. (n.d.). https://doi.org/10.3389/frevc.2026.1905945

Image Credits: AI Generated

DOI: 10.3389/frevc.2026.1905945

Keywords: carbon sequestration, Peruvian Amazon, coffee agroforestry, REDD+, payments for ecosystem services, biodiversity, Converting, forests, coffee, cultivation, Coffea, arabica