A methodology for monitoring carbon sequestration in Cork Oak woodlands

This dissertation presents a methodology for monitoring photosynthetic activity and carbon sequestration in cork oak woodlands, known in Portugal as Montado, by utilizing Solar-Induced Fluorescence (SIF) data. The study was conducted in the Companhia das Lezírias, Portugal, where the SIF data was collected using the Fluorescence Box (FloX), a cutting-edge hyperspectral field instrument designed for the passive measurement of SIF. The research aims to compare the seasonal trends and daily dynamics of SIF between two distinct vegetation components: a cork oak tree and the herbaceous layer, as well as to assess the influence of environmental factors such as absorbed photosynthetically active radiation (APAR), air temperature, and global radiation in SIF variability. This study investigates the relationship between SIF and other vegetative indices, to explore their ability to track plant health and productivity. The results revealed that APAR was the most significant predictor of SIF variability, followed by global radiation and chlorophyll-related indices. The results demonstrated that SIF data, particularly SIF A, can be used as a reliable indicator of long-term photosynthetic activity in perennial species such as cork oak, while SIF B provided more immediate signals of environmental stress. However, the study also highlighted limitations in interpreting SIF signals in herbaceous layers during periods of drought, where environmental artifacts such as soil reflectance may inflate SIF readings. The research concludes by emphasizing the potential of SIF, in combination with other vegetation indices, to offer valuable insights into the physiological state of Mediterranean ecosystems, enabling better management practices for carbon sequestration and ecosystem resilience in the face of climate change.