Modelling woody carbon dynamics in tropical dry forests: A case study of the Dry Chaco Region

• Tropical dry forests are critical ecosystems for woody carbon storage. • These systems are vulnerable to agricultural expansion and intensification. • We developed a model using Systems Dynamics to assess woody carbon stocks. • Native forest, forest management with livestock and traditional silvopastoral systems. • Our model was useful in predicting woody carbon dynamics on alternative land uses. Deforestation and forest degradation have escalated in tropical dry forests in recent decades, depleting biodiversity and carbon stocks. This is particularly meaningful for the Argentinean Dry Chaco, a deforestation frontier where silvopastoral systems could expand on more than 18 million hectares. Here, we evaluate long term forest and woody carbon dynamics of two silvopastoral systems: Forest management integrated with livestock (herein MBGI) and traditional silvopastoral (TSP), and compared these with undisturbed primary native forests. To do so, we developed a model using systems dynamics methodology, literature review, and expert elicitation, and then parameterized it with over 570 field sampling sites collected across the region. Our results show that in the long-term (i.e., 90 years), forest management integrated with livestock (MBGI) retained 53% more woody carbon than TSP, but 28% less than the undisturbed primary native forest. Moreover, MBGI maintained forest structure over time, with the shrub layer holding 27% of the total carbon stock. In the long term simulation, MBGI showed a positive carbon sequestration rate, whereas TSP showed a negative one. Overall, we provide a robust evaluation of forest population and carbon dynamics for alternative silvopastoral systems in the Dry Chaco region that could be adapted to other tropical dry forests. Our results highlight the medium- to long-term sustainability of semi-intensive silvopastoral systems which sustain forest attributes while allowing for the expansion of agricultural production. This is crucial for deforestation frontiers in tropical dry forests, where finding alternatives to deforestation is essential.