A computer model may help explain why trees bloom at the same time, a new study suggests.
In 2015, researchers developed a computer model showing that one of the most famous models in statistical physics, the Ising model, could be used to understand why events occur at the same time over long distances.
In the new study, which appears in the journal Proceedings of the National Academy of Sciences, they put their computer model to the test using thousands of real pistachio trees planted on a grid and found that it worked.
“Instances of synchronous behavior, when everything comes on at once, are found throughout nature…”
“We’re trying to understand the dynamics in time and space of ecological populations,” says senior author Alan Hastings, a professor in the environmental science and policy department at the University of California, Davis. “We were able to make use of a very large data set from more than 6,500 trees in a pistachio orchard and were able to show that ecological systems can be governed by the Ising model.”
The Ising model was developed to explain permanent magnets, like the kind that stick to a refrigerator door, but the authors showed it can also help explain how pistachio trees synchronize in an orchard.
In magnetic materials, forces between neighboring atoms tend to keep electrons aligned so their magnetic forces add together. The Ising model makes quantitative predictions of how neighbor-to-neighbor interactions can create alignments over large distances.
If neighboring trees are synchronized, it implies they are communicating somehow. While the authors do not identify the means of this communication, they suggest it may be a consequence of root grafting, where roots intertwine. Grafting may help one tree “tell” another that it’s time to produce, which may help neighboring trees synchronize their production. The Ising model helps predict how interactions between trees next to each other spread through the whole orchard.
“Instances of synchronous behavior, when everything comes on at once, are found throughout nature, from fruit and nut trees in orchards, to cone-bearing trees in the forest and even the sudden spread of some infectious diseases,” says lead author Andrew Noble, a project scientist in the environmental science and policy department at UC Davis at the time of the study. “Understanding these dynamics helps better explain ecological systems and their effects in natural and managed systems.”
Additional coauthors of the study are from UC Davis and the World Agroforestry Centre in Nairobi, Kenya and the University of Massachusetts, Amherst and Santa Fe Institute.
The study received funding from an Integrated NSF Support Promoting Interdisciplinary Research and Education (INSPIRE) grant from the National Science Foundation.
Source: UC Davis