This stunning visualisation of US immigration over 226 years will make you rethink how America's population has evolved

Courtesy of Pedro Cruz, Northeastern University.
  • Researchers at Northeastern University have visualized America’s immigration history as a tree trunk, with rings that delineate the waves and patterns in migration.
  • The colours represent groups of immigrants from different regions: Europe is green, Latin America is orange, Africa is red, Asia is pink, the Middle East is purple, and Oceania and Canada are blue.
  • In an animated version, the metaphorical tree trunk can be seen growing and evolving as the years tick by.

After more than 200 years of immigration, America’s population has evolved into a vast mosaic of nearly 330 million residents, whose ancestors hail from every corner of the world.

For researchers at Northeastern University, visualising the nearly unfathomable magnitude and intricacy of the issue was a challenge that could only be symbolized by a living organism: the rings of a growing tree.

In a simulated dendrochronology, also known as the scientific method of dating tree rings, data visualisation professor Pedro Cruz and journalism professor John Wihbey used the metaphor of tree growth to map out the country’s history of immigration using census data.

They even broke the immigration patterns down state by state:

Tree rings by stateCourtesy of Pedro Cruz, Northeastern University

Cruz told Business Insider that he first conceived the project last year while visualising population flows into the US.

“I work with metaphors in visualisation, and experimenting with new figurative ways to make information visible and evocative,” he said. “It came as a personal reaction to some discourses that we find echoed in some media nowadays: I wanted to make something that celebrates immigration and sheds an integrative light on it, while showing how long it has been around in the specific case of the US.”

Read more: Powerful photos and stories from the caravan show migrants’ harrowing journey to the US

Those patterns and trends within America’s immigration history are clear from the colours and shapes of the rings – in the 1800s, immigrants almost exclusively came from Europe, represented on the tree by green dots.

Tree ring visualisationCourtesy of Pedro Cruz, Northeastern UniversityThe colours on the tree rings represent different regions immigrants came from.

“For this I though a lot about the metaphor, and found that the tree rings metaphor works perfectly for this discourse – it shows an organism that took hundreds of years to grow, that was built on a large set of individual contributions (being the cells, the immigrants),” Cruz said.

Throughout the 20th Century, as more migrants came from Latin America, the tree rings skew southward and change to yellow dots to visualise the evolution. In more recent years, as Asian immigration has skyrocketed, the rings shift westward and the dots turn pink.

See an animation showing the last two centuries, showing the tree rings growing and evolving as the years tick by:

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