@InProceedings{SilvaWGSPGOA:2021:NeInLa,
               author = "Silva, Ricardo Dal'Agnol da and Wagner, Fabien Hubert and 
                         Galv{\~a}o, L{\^e}nio Soares and Streher, Annia Susin and 
                         Phillips, Oliver L. and Gloor, Emanuel and Ometto, Jean Pierre 
                         Henry Balbaud and Arag{\~a}o, Luiz Eduardo Oliveira e Cruz de",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {University of Leeds} and {University of 
                         Leeds} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Mind the gap: New insights on large-scale forest dynamics over 
                         Amazonian forests from airborne lidar and canopy gap data",
                 year = "2021",
         organization = "EGU General Assembly",
            publisher = "EGU",
             abstract = "Tree mortality has been pointed out as a key factor to quantify 
                         global forests carbon stocks and turnover. While there have been 
                         recent developments on observational studies aiming at detection 
                         and attribution of tree mortality using remote sensing data in 
                         temperate forests, the spatial and temporal distribution of 
                         tropical forests mortality is still poorly understood. Tropical 
                         forests pose a challenge for mortality detection due to its rich 
                         diversity of plant species and heterogeneous canopy structure, 
                         which also leads to the occurrence of very frequent and localized 
                         mortality events rather than widespread mortality as seen in some 
                         temperate forests. Here, we report on recent developments on 
                         estimates of spatialized forest dynamics over tropical forests 
                         leveraging large datasets of airborne lidar and a newly 
                         established link between canopy gaps and canopy mortality. Using 
                         multi-temporal lidar datasets collected at five Brazilian Amazon 
                         forests with varied forest structure, we linked static gaps, i.e. 
                         holes in the forest observed at one date, to dynamic gaps, i.e. 
                         gaps that opened from one date to another. Using 610 flight lines 
                         of airborne lidar data covering an area >2,300 kmē across the 
                         Brazilian Amazon, we mapped the static gaps and used them to 
                         analyze potential natural and human-induced drivers using 
                         generalized linear models. Finally, we produced estimates of 
                         annual dynamic gap rates (% yr-1) for the whole Amazon using the 
                         combination of the environmental-climate model and the 
                         static-dynamic gaps relationship. Our findings show well-defined 
                         spatial patterns of dynamic gaps over the Amazon, with 20-35% 
                         faster dynamics in the west and southeast than in the central-east 
                         and north. Higher gap fractions were more often found at southern 
                         and eastern Brazilian Amazon, bordering the deforestation arch, 
                         i.e. regions with increased human influence. Dynamic gaps showed a 
                         significant relationship with field mortality rates (Rē = 0.40), 
                         but with 60% lower magnitude. In fact, what we have detected is 
                         very likely mortality with the predominant emphasis of lidar on 
                         detecting uprooted and broken mode of death. The analysis also 
                         provided new insights on the dynamics of remote areas where we 
                         have never visited before. New challenges include testing the 
                         gap-method over other sites with multi-temporal data, developing 
                         methods to detect standing dead trees, and mapping other drivers 
                         such as liana-infested forests. Merging improved regional 
                         quantification of dynamic gap estimates with vegetation modelling 
                         offers potential to explore how forest dynamics is influencing 
                         carbon stocks and turnover, and how they may evolve in the 
                         future.",
  conference-location = "Online",
      conference-year = "19-30 apr.",
                  doi = "10.5194/egusphere-egu21-11046",
                  url = "http://dx.doi.org/10.5194/egusphere-egu21-11046",
             language = "en",
           targetfile = "EGU21-11046-print.pdf",
        urlaccessdate = "09 maio 2024"
}