Mortalidade de cacaueiros (Theobroma cacao L.) em várzeas após cheia extrema no baixo Rio Madeira
The cocoa has been cultivated for centuries in Amazonia floodplains. This was the product most exported of this region and nowadays it has been an important non-timber forest product for riverine populations of white water rivers. In 2014, the rivers water level in lower Madeira river reached the...
| Autor principal: | Simão, Marcos Vinícius Ribeiro de Castro |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/5127 http://lattes.cnpq.br/0371932049521169 |
| Resumo: |
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The cocoa has been cultivated for centuries in Amazonia floodplains. This was the
product most exported of this region and nowadays it has been an important non-timber
forest product for riverine populations of white water rivers. In 2014, the rivers water
level in lower Madeira river reached the highest level ever recorded, resulting in the
mortality of many cocoa trees on the floodplains. Despite some reports of cocoa tree
mortality after extreme floods, these are events rarely studied in the amazon region.
Then, the goals of this paper were: understand the floods dynamic in the lower Madeira
river; to estimate the cocoa tree mortality rate after an extreme flood; and to identify the
influence of environmental and dendrometric variables over this mortality rate. It was
found a growth trend of the higher water levels reached over the last three decades,
highlighting the flood of 2014, which exceeded 3.71 meters the mean of the maximum
levels of this historical series. It was observed that since the beginning of the 21st
century it has happened an increase in the cocoa plantations in the region, since the
majority (85%) of the cocoa plantations were set down over the last 15 years. This fact
potentialized the mortality caused by the extreme flood, considering that small cocoa
trees experience higher mortality rates after floods. The extreme flood occurred in 2014
caused the mortality of 100% of young cocoa tress and 46% of adult cocoa trees. Taking
into account only adult cocoa trees, those bigger in diameter experienced lower
mortality because they were more resistant to the action of the flow and the injuries
caused in the trunk. The increase in canopy cover contributed to lower mortality
probably by reducing the impact of logs brought by the flow and reducing the stress
caused by excess radiation in cocoa trees, which is a shade tolerant species. Mortality
was not influenced by the depth of the sediment layer deposited during the flood; this
result can be attributed to the species capacity to emit adventitious root from the trunk.
The variation in the flooding duration, between 70 and 105 days, also did not influence
mortality. It is possible that this result is due to the extreme magnitude of this flood,
which did not allow to sample cocoa plantations that went through less than 70 days of
flood. The pruning and the distance of the cocoa plantation at the riverbank also did not
influence the mortality. Thus, in view of the trend of increasing flood peaks in the lower
Madeira river and of intensification of new cocoa plantations in the region, the results of
this work are important steps for understanding these mortality events and for
adaptation of the cultivation of cocoa tree in the floodplains. |