To monitor the effects of climate change on forests, it is important to adopt integrated, in situ and satellite approaches aimed at analyzing phenology, that is, the different stages of leaf development through the different seasons. This is the conclusion of a study, published in the journal Ecological Indicators, conducted by scientists from the National Research Council’s Institute for Research on Terrestrial Ecosystems (CNR-IRET), the Edmund Mach Foundation, and the Universities of Tuscia, Bolzano, Caserta, and Florence. The team analyzed the integration of spectral data collected under the tree canopy with information obtained from satellite observations to assess how to accurately monitor the phenology of European beech forests. Indeed, changes in phenology are an optimal indicator of the effects of climate change, which can accelerate or delay different stages of vegetation development; however, very accurate data are needed for effective monitoring. As part of the investigation, The work suggests that TT+ devices are most effective in detecting rapid changes, especially during particularly critical periods such as leafing. Using a range of state-of-the-art technologies, the scholars recorded physical and functional parameters of trees, comparing the picture obtained from the ground with the large-scale view obtained from satellite data. The research team used under-canopy spectral data collected from Tree Talker© (TT) devices and Sentinel 2 satellite images that view forests from above, comparing data on the onset, duration, and end of growing and leaf development seasons.
TT+ sensors, in particular, experts report, showed superior accuracy in detecting points of phenological change, such as leaf opening and fall, due to their high temporal resolution compared to satellites, which can be hampered by cloud cover. “One of the key aspects of this study,” says Gaia Vaglio Laurin, first author of the paper, ”is the complementarity between the two methods: while satellite data provide useful information over large areas but not always accurate, TT+ sensors detect precise details at the level of individual trees or groups of trees. Integrating these two approaches is critical to better understanding how climate change is affecting European forests.”
Looking to the future and possible prospects of this investigation, the authors point out that the combined use of the two monitoring techniques could improve forest management by facilitating the identification of adaptive strategies in response to climate change. “Phenology monitoring,” Vaglio Laurin concludes, ”plays a central role in view of analyzing the effects and impacts of climate change. Our work shows that the integration of information from satellite and ground-based spectral sensors can improve forest phenology monitoring.”.
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https://www.sciencedirect.com/science/article/pii/S1470160X2301470X?via%3Dihub