Human history through tree rings: Trees in Amazonia reveal pre-colonial human disturbance
APRIL 3, 2019
by Max Planck Society
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.
Domesticated Amazonia
Until recently, forests in the Amazon Basin have often been argued to be "pristine" or the site of only small-scale human occupation and use prior to the arrival of European explorers in the 16th century. However, recent archaeobotanical, archaeological, palaeoenvironmental, and ecological research has highlighted extensive and diverse evidence for plant domestication, plant dispersal, forest management, and landscape alteration by pre-Columbian societies.
Nevertheless, human management of tropical forests has undergone a number of drastic changes with the rise of global industrialized societies. Many economically important trees dominate modern Amazonian forests, some of which have undergone domestication processes. Therefore, understanding the changes in forest management witnessed by Amazonian forests over the course of the last centuries has significant implications for ongoing human interaction with these threatened ecosystems.
"The results of this study demonstrate that Brazil nut tree growth reflects human occupation intensity and management. This is one more step to understanding the crucial interactions that led the Amazon forest to be the dynamic, humanized landscape it is today", says Victor Caetano Andrade, lead author of the study, of the Max Planck Institute for the Science of Human History.
More:
https://phys.org/news/2019-04-human-history-tree-trees-amazonia.html
