Allometric models for above-ground biomass, carbon and nutrient content of wild cherry (Prunus avium L.) trees in agroforestry systems

Abstract

Abstract Key message We provide a set of allometric models for wild cherry trees (Prunus avium L.) established in agroforestry systems. A total of 70 trees in southwestern Germany were surveyed using terrestrial laser scanning and analysed using quantitative structure models. The derived allometric models provide a stable base for biomass estimation in comparable agroforestry systems. Our biomass model, based on volume estimates converted to biomass, shows no significant differences to a previous study in the same region on the same species, although it was conducted on agroforestry trees under a different management regime. Context Wild cherry (Prunus avium L.) is a common tree species in agroforestry systems (AFS). Utilised for either fruit production or for high-value timber production, it is a highly relevant species, yet even basic allometric models are lacking. Aims The aim of this study was to develop a set of allometric models for wild cherry trees in AFS. Within this context, we present an innovative non-destructive approach to estimate bark and wood volume separately by applying bark thickness models to 3D models of trees. To assess model applicability to different AFS, we compared our allometric model for above-ground biomass with a previous biomass model for wild cherry trees under different management in the same region. Methods Wild cherry trees (n = 70) located within AFS in southern Germany were scanned with a terrestrial laser scanner. Quantitative structure models were used to derive tree dimensions and above-ground volume per tree. Using additional auxiliary data, the target variables were derived, and corresponding allometric models were fitted. Results The allometric models estimating above-ground volume, oven-dry biomass, carbon content and nutrient content based on diameter at breast height (DBH) showed excellent fits (R2adj ≥ 0.97). The comparisons with a similar study conducted in the same region suggested that management practices such as pruning have only a minor influence on the relationship between DBH and above-ground tree biomass. The nutrient content in the trees decreased in the order Ca > N > K > Mg > P. Conclusions The derived allometric models provide valuable information on this important agroforestry tree species. Our findings can both inform management practices in AFS and advance ecological understanding of these systems. Future research should focus on developing allometric models for other tree species relevant to AFS.