Sustainable Management of Bursera bipinnata: Relationship Between Environmental and Physiological Parameters and Resin Extraction

Copal is a non-timber forest product of historical, cultural, and industrial significance in Mexico. The use of unsustainable harvesting methods and a lack of understanding of the factors influencing their production have led to a decline in natural populations of resin-producing species. This study aimed to identify the dendrometric, edaphoclimatic, physiological, and resin extraction method variables with the greatest influence on resin yield in Bursera bipinnata using correlation analysis and multiple linear regression. The research was conducted in the Los Sauces micro-watershed, Morelos, Mexico, with a randomly selected sample of 70 trees. Nineteen explanatory variables were categorized into dendrometric, edaphoclimatic, physiological, and extraction method parameters. Variables significantly correlated with resin yield were diameter at breast height, crown diameter, crown volume, altitude, resin tapping faces on the stem, resin tapping faces on branches, total resin tapping faces, resin tapping face height, total resin tapping area, and the Normalized Difference Moisture Index (NDMI) in October. The regression model revealed that resin yield increased significantly with total tapping area (β=0.649) but decreased with greater incision length (β=−0.308) and higher NDMI values in October (β=−0.205), explaining 43.8% of the variation in resin yield. Results highlight the importance of tissue damage intensity, tree physiological status, and water availability as determinants of resin production. The model provides practical guidelines for optimizing extraction techniques, enabling sustainable harvesting that maintains tree vitality and supports long-term productivity in resin-harvesting communities.