Allometric models to estimate aboveground biomass of Pinus tecunumanii shade trees growing in agroforestry coffee systems

Abstract Accurate estimation of carbon stocks has become increasingly important considering the global need to understand and mitigate climate change. Species-specific allometric equations are essential tools for obtaining precise estimates of tree biomass, enabling simple and reliable carbon assessment. In South America, particularly in Peru, coffee is commonly cultivated under shade trees such as Pinus tecunumanii , forming agroforestry systems that enhance carbon sequestration. However, information on carbon cycling in coffee-based agroforestry systems remains scarce, and allometric models for this species are still lacking. This study therefore aimed to develop species-specific allometric equations for Pinus tecunumanii , a shade tree used in coffee agroforestry systems in the Peruvian Andes. A total of 22 shade trees were sampled, with diameters at breast height (DBH) ranging from 9.9 to 43.8 cm and total heights (H) from 6.3 to 38 m. Power-law and exponential models were fitted to predict aboveground biomass from DBH and H. On average, aboveground biomass was distributed as follows: 59.8% in the stem, 14.5% in the branches, and 25.8% in the foliage. Using allometric equations, carbon stock per tree ranged from 8.8 to 469.2 kg. The developed model provides a practical and accurate tool for estimating aboveground biomass and carbon stocks in Pinus tecunumanii shade trees within coffee agroforestry systems. Its application will improve the precision of carbon accounting and contribute to sustainable management practices in Latin American coffee landscapes.