@InProceedings{CardosoOlivNobr:2010:CoDeFi,
               author = "Cardoso, Manoel Ferreira and Oliveira, Gilvan Sampaio de and 
                         Nobre, Carlos Afonso",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Combined deforestation and fire occurrence in long-term models of 
                         forests and savannas in the Brazilian Amazonia",
            booktitle = "Proceedings...",
                 year = "2010",
         organization = "The Meeting of the Americas.",
            publisher = "AGU",
             keywords = "biosphere, atmosphere interactions, modeling, eco-hydrology, 
                         land.",
             abstract = "According to climate and hydrological conditions, large tropical 
                         areas would potentially be covered by forests. Remote sensing and 
                         field surveys, however, show how these regions may differ from 
                         their potential original states because land use, such as logging, 
                         agriculture and pastures. Related processes also contribute to the 
                         replacement of forests by secondary and degraded vegetation, and 
                         to the establishment of savannas. Fires are such a process 
                         normally associated to the current land-use practices in the 
                         tropics. Because savannas are adapted to fires and benefit from 
                         their occurrence, forest-to-savanna transitions are potentially 
                         very stable near deforestation areas. Here we present a method to 
                         account for deforestation and fires on the distribution of 
                         tropical and seasonal forests and savannas in the Brazilian 
                         Amazonia, and underline some strategies for implementing it in 
                         long-term vegetation models. We analyzed soil-hydrology and fires 
                         occurrence data together with the results from the potential 
                         vegetation model CPTEC-PVM2, and explored two factors used to 
                         determine the potential distribution of major biomes in that 
                         model. One is a soil-moisture seasonality index (D) which is lower 
                         (higher) for places where the soil presents longer (shorter) dry 
                         periods. Other is an above-ground wetness index (H) which is lower 
                         (higher) for longer (shorter) periods of dry atmospheric 
                         conditions. The analysis indicated the most common values for both 
                         indexes in areas potentially covered by tropical forests in the 
                         Brazilian Amazonia that had low, medium and high fire activity in 
                         the years 1998-2005 according to active-fire detections with the 
                         Tropical Rainfall Measuring Mission - Visible and Infrared Scanner 
                         (TRMM-VIRS). For each fire-activity class, we determined the 
                         distribution of values for both indexes and found the values below 
                         which deforestation/fire degradation were relatively more 
                         frequent. We now plan to use these relations when accounting for 
                         deforestation/fires in projections of the spatial distribution of 
                         the major biomes in the region. For that, we selected and discuss 
                         the following strategy that we consider appropriated. First, we 
                         assume that land-use dynamics and policy currently observed in the 
                         Brazilian Amazon will remain in the future. Second, we consider 
                         that deforestation/fires will affect forests only in grid cells of 
                         tropical and seasonal forests that are located adjacent (<150km) 
                         to savannas, because the access to the forests is facilitated by 
                         the savannas where fires are also a natural feature. In summary, 
                         if a place projected to be covered by tropical or seasonal forest 
                         presents both indexes H and D below certain thresholds, and the 
                         area is adjacent to a savanna, then tropical forest will be 
                         adjusted to seasonal forest. In case of a seasonal forest it will 
                         be adjusted to savanna. Although our method may represent an 
                         underestimation of fire effects by not considering direct 
                         transitions from tropical forests to savannas, it allows for 
                         quantifying changes in vegetation cover including human factors, 
                         and based on simple general relations derived using data from the 
                         region.",
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "8-12 Aug. 2010",
             language = "en",
           targetfile = "Cardoso_Combined.pdf",
        urlaccessdate = "30 abr. 2024"
}