Growth of agroforestry trees in real and simulated ecosystems

The thesis explores tree growth both in the field and under controlled environmental conditions, focusing on the potential of Microcosm, a model of growth chamber, to study tree species and ecosystem dynamics. The project aims to assess the effectiveness of Microcosm in investigating tree growth by monitoring ecophysiological and biochemical traits. While drawing ecosystem-level conclusions solely from growth chamber experiments is limited, combining controlled-environment studies with field investigations is essential to analyse correlations between the ecophysiological traits of individual trees and broader ecosystem dynamics. The purpose of this research is to enhance the understanding of the current and potential applications of the Microcosm device in studying tree dynamics through an ecophysiological approach. The study specifically aims to validate the efficacy of Microcosm in inducing responses in tree species comparable to those observed in real ecosystems, to explore its potential for studying tree and plant responses to pollutants, and to identify its practical applications in agroforestry design and management. These goals are pursued through field data collection and the measurement of biometric and morphological parameters in growth chamber experiments. To achieve these research objectives, a dual approach is adopted, combining controlled-environment experiments and field surveys to investigate tree growth under the same stress factor. This approach allows for the assessment of tree responses both in real-world conditions and, in parallel, under controlled conditions. In defining a common stress factor applicable to both controlled environments and real ecosystems, exploratory analyses identified railway infrastructure as a site with high copper concentrations in soils along embankments, where black locust (Robinia pseudoacacia L.) is the dominant and most widespread species in the study area (Veneto region, north-east of Italy). Consequently, black locust was selected as the target species for investigation, and high copper concentration in soil was identified as the stress-inducing factor. Two parallel investigations were conducted to understand the effects of copper contamination. In the field, the development of black locust in a Cu-contaminated environment, specifically along railway infrastructure, was analysed. Under controlled conditions, black locust seedlings growth was tested in extreme Cu-concentration soil using Microcosm experiments. This approach highlights the strengths and limitations of both controlled-environment research and field data collection. By integrating these methodologies, the research underscores the importance of combining experimental precision with real-world conditions to achieve a more comprehensive understanding of ecological dynamics.