Trees in Amazonia reveal pre-colonial human disturbance
In a new paper published in PLOS ONE, an international team of scientists reports the combined use of dendrochronology and historical survey to investigate the effects of societal and demographic changes on forest disturbances and growth dynamics in a neotropical tree species, the Brazil nut tree. The study, led by scientists from the National Institute for Amazonian Research, alongside colleagues from the Max Planck Institute for the Science of Human History, shows the influence of human populations and their management practices on the domestication of rainforest landscapes. The researchers used non-destructive sampling, in which small samples are removed from the bark to the center of the trees, and compared tree-ring data from cores of 67 trees. This is the first study of human influence on the growth of trees that extends as far back as 400 years, to pre-colonial times in that region of Brazil. This work also reinforces that pre-colonial populations left important imprints in the Amazon, contributing to changing forest structure and resources through time.
Understanding how forest management has changed following the arrival of European colonists and the rise of industrial powers over the course of the past centuries has implications for the future of sustainable forestry and conservation in Amazonia. “Our findings shed light on how past histories of human-forest interactions can be revealed by the growth rings of trees in Amazonia,” explains Caetano Andrade. “Future interdisciplinary analysis of these trees, including the use of genetics and isotopes, should enable more detailed investigations into how human forest management has changed in this part of the world, through pre-colonial, colonial, and industrial periods of human activity, with potential implications for conservation.”