The ‘Rule of Trees’ by Leonardo da Vinci, which has long been employed by science to depict and understand tree structures and function, has been debunked by a recent study. This research, conducted by scholars from Bangor University in the UK and the Swedish University of Agricultural Sciences (SLU), suggests that Leonardo’s rule doesn’t align with the internal vascular systems of trees, potentially explaining why larger trees are more susceptible to drought and climate change.
Leonardo da Vinci’s fascination with drawing led him to analyze the size ratios of various objects, including trees, to create more accurate representations. His ‘Rule of Trees’ posited that all branches of a tree, at any height, should collectively be as thick as the trunk itself.
Previously, it was assumed that this rule could also be applied to the vascular channels responsible for transporting water within a tree, with the sizes of individual channels decreasing proportionally as branches narrowed, while still maintaining the trunk’s volume. This concept was integral to metabolic scaling theory.
However, the scientists from Bangor University and SLU, publishing their findings in the respected journal PNAS, have demonstrated that this model isn’t entirely accurate when applied to a tree’s internal vascular structures.
Efficient movement of water and nutrients through a tree’s vascular system depends on maintaining ‘hydraulic resistance.’ Researchers Ruben Valbuena and Stuart Sopp have determined that to uphold hydraulic resistance, there is a point at which the ‘Rule of Trees’ no longer holds true.
To efficiently transport liquids from roots to leaves, a tree’s vascular channels must maintain a specific dimension. Consequently, as a tree extends towards its extremities, it needs to reduce its volume, resulting in a higher ratio of capillary channels to the surrounding plant mass.
Dr. Ruben Valbuena, formerly of Bangor University and now a Professor at SLU, explained, “While Leonardo’s Rule of Trees is valuable for artists, it doesn’t stand up at the microscopic level. We believe our calculations refine metabolic scaling theory and enhance our comprehension of the entire plant system. These recalculations may also shed light on why large trees are more vulnerable to drought and climate change.”
Co-author Stuart Sopp, currently pursuing a Ph.D. in Environmental Science at Bangor University, noted, “One of our objectives was to devise a ratio for estimating tree biomass and carbon in forests. This new ratio will be instrumental in assessing global carbon capture by trees.”
Reference: “Vascular optimality dictates plant morphology away from Leonardo’s rule” by S. B. D. Sopp and R. Valbuena, September 18, 2023, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2215047120
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Frequently Asked Questions (FAQs) about Tree Vascular Systems
What is the ‘Rule of Trees’ by Leonardo da Vinci?
Leonardo da Vinci’s ‘Rule of Trees’ is a concept he developed to create accurate representations of trees in his drawings. It states that all branches of a tree at every stage of its height should collectively be as thick as the trunk when put together.
How was the ‘Rule of Trees’ applied in science?
Scientists previously applied the ‘Rule of Trees’ to model tree function, including the internal vascular structures that transport water within trees. This concept was considered part of metabolic scaling theory.
What did the recent study discover about the ‘Rule of Trees’?
The study conducted by researchers from Bangor University and the Swedish University of Agricultural Sciences found that the ‘Rule of Trees’ is not accurate when applied to the internal vascular structures of trees. It doesn’t align with the need for hydraulic resistance in the tree’s vascular system.
Why is the study’s finding significant?
This finding challenges our understanding of tree physiology and may explain why larger trees are more vulnerable to drought and climate change. It also has implications for estimating tree biomass and carbon capture in forests.
Where can I find the full research paper?
The full research paper, titled “Vascular optimality dictates plant morphology away from Leonardo’s rule,” was published in the Proceedings of the National Academy of Sciences on September 18, 2023, with DOI 10.1073/pnas.2215047120. You can access it through scientific databases or academic libraries.
More about Tree Vascular Systems
- Proceedings of the National Academy of Sciences (PNAS): Access the full research paper titled “Vascular optimality dictates plant morphology away from Leonardo’s rule” with DOI 10.1073/pnas.2215047120.
- Bangor University: The institution where some of the researchers, including Dr. Ruben Valbuena and Stuart Sopp, were affiliated.
- Swedish University of Agricultural Sciences (SLU): The institution where some of the researchers, including Dr. Ruben Valbuena, are associated.
- Leonardo da Vinci’s ‘Rule of Trees’: Learn more about Leonardo da Vinci’s ‘Rule of Trees’ on Wikipedia.
