Tree growth and soil recovery in Amazonian lands degraded by coca cultivation and grazing

Soil degradation resulting from illicit coca cultivation and unsustainable grazing practices poses amajor challenge toecosystem restoration inthe Peruvian Amazon. This study evaluates the potential offast-growing tree species torehabilitate degraded soils while producing economically valuable timber. Monoculture plantations of<i>Corymbia torelliana</i> (eucalyptus), <i>Calycophyllum spruceanum</i> (capirona), <i>Colubrina glandulosa</i> (shaina), and <i>Cedrelinga cateniformis</i> (tornillo) were established onformer coca and pasture lands inthe Alto Huallaga Valley. Weassessed tree growth and key soil physicochemical properties – including soil organic matter (<i>SOM</i>), bulk density (<i>BD</i>), pH, extractable phosphorus (P), and cation exchange capacity (<i>CEC</i>) – intopsoil (0–10 cm) and subsoil (10–40 cm) layers. Eucalyptus and tornillo showed the highest diameter growth, while tornillo plots had significantly higher <i>SOM</i> levels. Soil pH was strongly acidic across all plots, and subsoil Pwas lowest under tornillo. <i>CEC</i> was highest in eucalyptus and capirona plots. Our findings suggest that tree plantations, particularly with eucalyptus, capirona, and tornillo, represent a viable strategy for the sustainable use and rehabilitation of soils formerly used for coca cultivation and grazing.