There has been a large amount of research dedicated to proving that forests and the trees which reside within it are more than independent individuals residing close to together. Largely pioneered by the work of ecologists such as Dr. Suzanne Simard, there have been large strides forward in the understanding of the levels of interconnectedness and interactions between trees. In forests, there is no other role as crucial to this structure as that of the central, hub trees or “mother” trees and the networks they utilize. These mother trees play a critical role in the development, health and life of the trees around it and within their ecosystem, including many tree and fungal species (Simard). Furthermore, these mother trees, the communication and the interactions between these species are all able to come together to have large impacts on the success that forest management tactics have. The health, viability and response to varying disturbances will all also influence the future trees planted afterwards, based on how the stand was managed in the present. Mycorrhizae is made up thousands of thread-like projections which connect to each other forming a network, with itself and with other mycorrhizal networks of differing plants and species which allow it to grow and spread underneath the forest floor. This is able to be facilitated through these interactions between mycorrhizal networks under the soil, these networks have the ability to transfer “carbon, nutrients, water, defense signals and allelochemicals” (Simard et al. 39). Thus, it can be seen that these mycorrhizal networks are responsible for providing the avenues which trees are able to communicate with one another. The image below (see fig. 1) is able to provide just a small analysis of the complexity of these relationships between trees which occur in forest ecosystems.
Fig. 1: Illustration showing mother trees and their placement in forest through mycorrhizal network pathways. (Beiler et al 2010)
The large darker circles represent the mother trees and the pathways that are connected to it, these pathways are key to developing appropriate forest and stand management systems (Simard).
A common silviculture management system is clear-cutting, which results in the loss of these central mother trees and large disruptions to these complex networks. As Simard states, these mycorrhizal pathways allow for mother trees to protect growing trees in the understory and share information to growing seedlings, even going as far to recognize their own kin (Simard). When these trees are lost due to silvicultural practices like clearcutting, it loses the ability for not just mother trees, but other trees, to share their benefits like understory protection, nutrient receival and information about disturbance resistance response and warning; through the mycorrhizal pathway between them (Gilbert and Johnson 83). Whether these mother trees have the ability to “knowingly” pass along their information and nutrients is a highly controversial topic, or if they are doing so out of self-interest as we commonly have known species to act out of. However, the ability for warning signs to be passed through mycorrhizal networks within ecosystems is not controversial and widely accepted. Though the “why” is not known, there is significant research proving it to be true that trees have this ability. Those who manage forests must understand this because it is key to ensuring stand survival and the surrounding health of sections which are subjected to silvicultural management practices. With the loss of sections of forest, and in turn mother trees, the ability for forests to share warning messages to other trees is also negatively impacted as well as their ability to recover afterwards, “mycorrhizal networks contribute to forest resilience through their role in regeneration following disturbance,” (Pringle 51). Mother trees are unique due to their age because they are able to use their age as a strength in having a long history of detecting and responding to disturbances. As climate change inevitably worsens, it is assumed that the amount of ecosystem disturbances will also increase and forest management will have to keep playing this game of catch-up; if it continues behind in the understanding of the significance of mycorrhizal networks. One must be aware of the necessity for these mycorrhizal networks, and in turn the mother trees, in order for an ecosystem to remain healthy. It is crucial that forest management systems keep this in mind in order to reduce the impacts of climate change, amongst other ecological disturbances and keep ecosystems thriving.
Works Cited
Beiler et al 2010, Image published in Yale Environment 260, September 1, 2016.
Gilbert, L. Johnson, D. “Chapter Four: Plant-Plant Communication Through Common Mycorrhizal Networks” Advances in Botanical Research. Vol. 82. 2017 Pages 83-97.
Pringle, Anne. “Mycorrhizal Networks” Current Biology. Vol. 19. No. 18. 2009. Page 51.
Simard, Suzanne W. Beiler, Kevin J. Bingham, Marcus A. Deslippe, Julie R. Philip, Leanne J. Teste, François P. “Mycorrhizal networks: Mechanisms, ecology and modelling” Fungal Biology Reviews. Vol. 26. No. 1. 2012. Pages 39-60.
Simard, Suzanne W. “How trees talk to each other” TED. June 2016. Lecture
This activity was able to increase knowledge of forestry and facets within that discipline, as well as research skills and finding adequate sources to back up claims.