1 Vol.:(0123456789) Scientifc Reports | (2021) 11:23464 | https://doi.org/10.1038/s41598-021-03004-5 www.nature.com/scientificreports Carbon storage estimation in a secondary tropical forest at CIEE Sustainability Center, Monteverde, Costa Rica Alexandra Paniagua‑Ramirez 1 , Oliwia Krupinska 2 , Vicki Jagdeo 2 & William J. Cooper 3* Secondary growth tropical rainforests have the potential to sequester large amounts of atmospheric carbon dioxide and as such are an important carbon sink. To evaluate a local forest, a Carbon Neutrality Program was initiated at the Council on International Educational Exchange, San Luis Campus, Monteverde, Costa Rica. The study was conducted on 50 hectares of forest classifed as Premontane Wet Forest. The forest, part of the Arenal‑Monteverde Protected Zone, is estimated to be aproximately 50 years old and is in the upper regions of the San Luis valley at 1100 m elevation. Assessment of the carbon stock in trees was carried out in two permanent, 1 hectare plots, 100 m by 100 m, Camino Real and Zapote. The plots were divided into 25 subplots, 20 m by 20 m totaling 400 m 2 per subplot. Ten subplots in each area were studied which represented 1.6% the total surface area of the forest. All of the trees were measured within the subplots that had a diameter at breast height ≥ 10 cm and the height of 10% of the trees measured. The estimated total CO 2 sequestered by the campus forest was 18,210 ton (in 2019). Carbon dioxide is recognized as the primary greenhouse gas of the four gases that contribute the most to global warming. Tey include, carbon dioxide, CO 2 (81%); methane, CH 4 (10%); nitrous oxide, N 2 O (7%); and, halogen containing gases, CFCs (chlorofuorocarbons) (3%) 1–3 . Carbon dioxide results primarily from the combustion of fossil fuels which are derived from plants. Coal originates from decayed plant material occurring in swampy environments and is buried over geologic time. Oil originates from the phytoplankton and other organic matter that accumulates in oceanic sediments and afer burial migrates underground to reservoirs. Coming full circle, Dyson in 1977 was the frst to propose removing CO 2 from the atmosphere using plant photosynthesis 4 . Te present study further explores the importance of carbon capture and sequestration in a neotropical rainforest. Te concentration of carbon dioxide in the atmosphere has increased from preindustrial concentrations of approximately 280 ppm (parts per million by volume) 5 to the present 419 ppm worldwide 3,6–8 . As atmospheric CO 2 has become a central focus in climate change science the study of all aspects of the biogeochemical carbon cycle is the focus of much research 1 . One of the most important aspects of the carbon cyle, is the estimation of the halfife of CO 2 in the atmosphere 9–13 . However, because of the complexity of the carbon cycle, the estimates range from 30 to 95 years 14 . If one considers the long CO 2 concentration tail in some models, it has been sug- gested that the halfife could be as long as 300 years 15 . Better constraining these estimates is a very active area of research and it is possible that the Climate Model Intercomparison Project now in its sixth iteration (CMIP6) will lead to better estimates of atmospheric CO 2 lifetimes 16,17 . Limiting climate change will require that the atomspheric concentration of CO 2 is stabilized 18,19 . Te IPCC (2018) report entitled “Global Warming of 1.5 °C” emphasizes that new or renewed eforts are needed to reach the goal of stabilizing atmospheric concentrations of CO 2 20 . Studies have been published addressing stabilizing atmospheric CO 2 concentrations 21–24 . However, the concentration of CO 2 continues to rise a little over 2 ppm per year and forests are likely to play an important role in the future 5 . Te importance of forests was reviewed in a report prepared by the World Resources Institute 25 , and more recently by the IPCC 26,27 . Forests (or planting forests) can be thought of as reverse engineering human defor- estation and providing a natural sink for CO 2 28–30 . It is estimated world-wide, that of the 4.06 billion hectares of OPEN 1 Council On International Educational Exchange, Sustainability Center, Monteverde, Costa Rica. 2 Lehigh University, Bethlehem, Pennsylvania, USA. 3 Pierella Rainforest Reclamation Project, 324 Main Street, Suite 1322, Laurel, MD 20707, USA. * email: wcooper@uci.edu