Riparian and cloud forests are the ones that accumulate the most carbon in the Nicaraguan rainforest

According to Global Forest Watch , northern Nicaragua boasts over four million hectares of tropical forests, a verdant tapestry that acts as a vast carbon sink. However, not all areas store the same amount: behind the general label of “tropical forest” lie distinct forest types, each with its own climate, species, and capacity to retain carbon.

A new study published in Forest Ecosystems and led by Dr. Oscar Lanuza, professor and researcher at the National Autonomous University of Nicaragua in Managua (UNAN-Managua) and CREAF, has analyzed the five most common forest types in Nicaragua - cloud forests, riparian forests, transitional forests, pine-oak forests, and tropical dry forests - and demonstrates that riparian forests - those that grow along watercourses, such as rivers or streams - and cloud forests - common in the higher parts of the mountains and typically shrouded in mist - concentrate the greatest species richness and carbon; in fact, they store up to four times more carbon than dry forests , which are normally located in the lower latitudes of valleys and in the lowlands of the slope facing the Pacific Ocean throughout the Central American corridor.

To carry out the research, the team analyzed 4,495 trees from 239 different species . Specifically, they established 40 permanent sampling plots within the Miraflor-Moropotente protected landscape, a 45,000-hectare area that concentrates an enormous variety of ecosystems within a very small area. In the plots, they cataloged each tree and calculated the amount of carbon stored in its aboveground biomass—crowns, branches, and trunks. “In fact, we have provided information on functional attributes—for example, wood density—of more than a hundred species that were not recorded in international databases,” adds Lanuza. The fieldwork was also complemented with satellite imagery and machine learning models to more accurately estimate the total carbon present in the aboveground biomass and soil of the study area.

Regarding forest classification, the study describes cloud forests as extending across the high, humid zones, perpetually shrouded in mist and covered in mosses, ferns, and large trees. In this area, biodiversity is enormous, with an average of up to 30 tree species found in a single plot.

Along rivers and other seasonal or intermittent watercourses grow what are known as riparian forests , with lush vegetation and fertile, moist soil that fosters a high diversity of species. “These forests retain slightly more water than cloud forests, almost 5% more,” adds Lanuza. Here, the variety of species is even greater, with an average of 45 tree species found in each plot. “To give you an idea of the great diversity this represents, there are about 111 tree species in the entire Iberian Peninsula, so in just a quarter of a hectare, these tropical ecosystems can contain almost half of all the tree species richness we have on the peninsula.”

Between the dry valleys and the high mountain ranges lie transitional forests , which mix species from dry and humid environments and retain about 40% less carbon than riparian forests, but more than dry forests. On the cooler, higher slopes are pine-oak forests , dominated by a few species of conifers and oaks, which store about 65% less carbon than riparian forests. And in the lowest altitude areas, with a sunnier and seasonally arid environment, grow dry forests, with less vegetation and a storage capacity 75% lower than riparian and cloud forests.

The study warns that global climate models often underestimate the role of tropical forests by treating them as uniform ecosystems. “Tropical forests are often discussed as if they were a single entity, but there is enormous variety: from pine and oak forests to rainforests,” explains Guille Peguero, co-author of the study, professor at the University of Barcelona, researcher at IRBio-UB, and researcher affiliated with CREAF.

In fact, Global Forest Watch indicates that Nicaragua's tropical forests will experience 140,000 hectares of annual forest loss by 2025. According to the team, it is more urgent than ever to design policies that effectively protect the forests, safeguard their biodiversity, and preserve the vital functions they provide, such as atmospheric carbon sequestration.

The research also involves CREAF researchers Josep M. Espelta, Adrià Descals and Josep Peñuelas, the latter two also being researchers at CSIC.

This study was made possible thanks to funding from the Franklinia Foundation. "In countries of the Global South like Nicaragua, it is often difficult to access funding sources that help promote both environmental knowledge and conservation. This project has not only contributed to these two objectives but has also strengthened the collaborative ties that UNAN-Managua has historically had with CREAF and with Catalan universities such as UB and UAB," concludes Guille Peguero.

Reference article: Lanuza, OR, Descals, A., Espelta, JM, Peñuelas, J., & Peguero, G. (2025). Variation of above-ground tree biomass and soil carbon stocks across neotropical forest types. Forest Ecosystems. DOI: https://doi.org/10.1016/j.fecs.2025.100386