Peatlands dominated by cushion-forming species have been recognised for their high rates of soil carbon storage, along with their crucial importance in local pastoral systems, and in water supply and regulation, in the tropical and subtropical Andes. Cushion-forming species in Andean peatlands are known to have high rates of aboveground productivity, but there have been few studies and direct methods for quantifying their productivity. Here we describe the use of 3D digital models to estimate the aboveground biomass of Plantago rigida, one of the most common cushion-forming species of the tropical Andes. Using Structure from Motion (SfM) photogrammetry we reconstructed high-precision 3D models and, using traditional methods, obtained the dry biomass and carbon contents of 13 P. rigida cushions in three peatlands in northern Ecuador. Linear regression models were performed to assess the relationship of cushion volume vs. dry biomass, and also the area vs. carbon content of cushions. We found highly significant (linear) relationships in both cases, indicating the potential use of SfM photogrammetry to evaluate the annual productivity, carbon and water storage of cushions, along with microtopography effects on plant–plant interactions, water flow routing, and disturbance effects in cushion-dominated peatlands.