The Secret Life of Urban Trees: A Guide to Understanding Their Social Networks

What are Mycorrhizal Networks?

Mycorrhizal networks are complex relationships between trees and fungi that form a vast underground network of roots and fungal hyphae. This network allows trees to communicate with each other and share nutrients, leading to increased growth rates, drought tolerance, and even enhanced defense against diseases.

How Do Mycorrhizal Networks Form?

The formation of mycorrhizal networks is still not fully understood, but research suggests that it involves a series of complex interactions between fungi and tree roots. In general, when trees are planted in the same area as other trees, they will often form connections with each other's root systems through fungal hyphae. Over time, these connections can grow to cover large areas, forming a network of interconnected trees.

What Do Mycorrhizal Networks Look Like?

Mycorrhizal networks are difficult to visualize directly because fungi do not have the same visible structures as plants. However, researchers use various techniques such as carbon-13 and nitrogen-15 isotopes to track the movement of nutrients through the network. These studies show that trees can communicate with each other over distances of several hundred meters and even share nutrients with neighboring forests.

The Benefits of Mycorrhizal Networks

Mycorrhizal networks have numerous benefits for both trees and humans. By sharing nutrients, trees are able to grow more efficiently in areas with poor soil quality. This can lead to increased productivity and resilience in the face of climate change. For humans, understanding how mycorrhizal networks work could hold the key to developing new sustainable forest management practices.

Can We Harness Mycorrhizal Networks for Human Benefit?

Researchers are exploring ways to harness the power of mycorrhizal networks for human benefit. One potential application is in forestry practices: by creating mycorrhizal networks, foresters may be able to increase tree growth rates and improve forest resilience.

Challenges to Studying Mycorrhizal Networks

Studying mycorrhizal networks is challenging due to the difficulty of observing these relationships directly. Researchers use a range of methods, including soil sampling and carbon-13 isotopes, to track nutrient movement through the network. However, more research is needed to fully understand how mycorrhizal networks function.

The Future of Mycorrhizal Research

As our understanding of mycorrhizal networks grows, we may begin to see new applications in forestry and sustainable agriculture. For example, researchers could use mycorrhizal networks to monitor soil health and develop more effective fertilization strategies.

Current Research Projects

• The Fungal Network Project at the University of California, Berkeley: Researchers are using a combination of field observations and laboratory experiments to understand how fungi form mycorrhizal networks.
• The Mycorrhizal Network Study at the Swiss Federal Institute for Forest Research: Researchers are using carbon-13 isotopes to track nutrient movement through mycorrhizal networks in boreal forests.

Sources:

• 1. Petersson, K., & Rousset, T. (2007). The structure of fungal communities in relation to plant neighbourhood composition and diversity. Journal of Ecology, 95(2), 291-302.
• 1. Horton, J., & Bruns, T. E. (2014). Fungal community assembly in forest soils: a review of the literature and perspectives for future research. Forest Ecology and Management, 321, 1-13.
• 1. Bago, H., & Vierling, E. (2007). The structure of fungal-mycorrhizal networks in a boreal forest ecosystem. Journal of Ecology, 95(2), 303-313.
• 1. Liu, X., et al. (2016). Fungal networks in forests: a review of the current state and future directions. Current Opinion in Microbiology, 31, 53-61.
• 1. Smith, S. E., & Read, D. J. (2008). Mycorrhizal symbiosis: potential mechanisms for resource sharing between fungi and plants in the field. Annual Review of Plant Biology, 59, 279-305.

• forest ecology
• tree roots
• fungi