Ecofunctional Factors Associated with Resin Yield of Bursera bipinnata in Agroforestry Systems of Tropical Deciduous Forest

The production of resin from Bursera bipinnata, a species native to the tropical deciduous forest (TDF), known as copal, represents a crucial source of income for rural Mexican communities. This study evaluated associations between ecofunctional gradients and resin yield using principal component analysis (PCA), hierarchical cluster analysis, and a multiple linear model. Ecological, edaphic, dendrometric, and management variables were evaluated in 27 trees established in agroforestry systems (AFS) in the municipality of Tepalcingo, Morelos, Mexico. Horn’s parallel analysis supported the retention of three principal components, which explained 63.66% of the total variance. The multiple linear model was significant (F(5,21)=3.23, p=0.0256; R2=0.435; adjusted R2=0.300). PC1 was positively associated with log-transformed resin yield (β=0.400, p=0.0245) and was characterized by negative loadings for total tree height (TH), total fungi (TF), soil organic matter (OM), actinobacteria (AC), available phosphorus (P), and total nitrogen (TOTN), and a positive loading for elevation (ALT). In contrast, PC3 was negatively associated with log-transformed resin yield (β=−0.408, p=0.0269) and was characterized by negative loadings for soil bulk density (BD) and magnesium (MG), and a positive loading for soil moisture content (MC). Trees from site S2 also showed lower log-transformed resin yield than those from the reference site S1 (β=−1.786, p=0.0067), whereas no significant difference was detected between S3 and S1. Although the clusters differed in their observed mean resin yield, these differences were not statistically significant. Overall, the findings indicate exploratory associations between resin yield and multivariate gradients integrating ecological, edaphic, dendrometric, and management attributes within the sampled trees and study sites.