Researchers from Bangor University and the Swedish University of Agricultural Sciences have found that Leonardo da Vinci’s “rule of trees” does not hold true when applied to the internal structures of trees. Da Vinci developed this rule to accurately draw trees, stating that all branches are equal in thickness to the trunk when put together. It had been accepted that this rule could also be applied to the vascular channels that transport water through a tree. However, the recent study shows that this model is not entirely correct.
To efficiently transport water and nutrients from the roots to the leaves, a tree’s vascular system must maintain hydraulic resistance. The researchers calculated that in order for hydraulic resistance to work effectively, the rule of trees cannot hold true. As the tree reaches its extremities, the volume needs to decrease, causing a higher ratio of capillary to the surrounding plant mass. This means that the individual channel sizes do not decrease at the same ratio.
The study’s findings have important implications for understanding the plant system as a whole. It may explain why large trees are more susceptible to drought and climate change. The researchers also aim to develop a ratio that can be used to estimate tree biomass and carbon in forests, aiding in calculating global carbon capture by trees.
This study refines our understanding of tree morphology and challenges the long-held belief in Leonardo da Vinci’s “rule of trees”. By delving into the internal vascular structures, scientists can gain insights into how trees efficiently transport water. Further research in this area could have far-reaching implications for ecology and understanding the impact of climate change on trees.
– Bangor University
– Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2215047120)