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Archive for September, 2016

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Trees are a source of fascination, largely because of the length of their individual lifespan, and their impressive size. They are living things that seem almost inert, because of the long time scale through which their reactions occur. We often regard trees as more of a community than a population, because they rarely exist in pure stands… The more we come to understand about trees, the more this seems the correct approach.

 

Recent discoveries about the relationships between trees and soil fungi have opened some new and very fascinating philosophical questions about how to define an organism and what constitutes intelligence.

 

The cell, as should be common knowledge, is the smallest unit of life–meaning that it is the smallest thing that carries out all the functions we define as biotic functions (i.e. growth, response to stimuli, reproduction, etc). Cells make up networks that function together known as organs, and organs function together as organisms… This is just the beginning of telescopic categories in the organization of life.

 

One of the systems in our own bodies in which cells function together is the nervous system. Our nerves receive a stimulus, that is transmitted by electrical signals to our brain. The brain then decides to respond and this is transmitted back to the part of the body that received the stimulus.

 

The more we come to understand the relationship between trees, the more forests begin to resemble vast networks of nerves in an organism. Trees receive a stimulus, from an insect pest for instance, and they send a chemical message down to their roots. Attached to tree roots are tiny fibrous fungi, that transfer these chemical signals between trees. The trees can than produce tannins to give their leaves a foul taste and prevent insect damage.

 

The mycorrhizal fungi play an important role as a sort of nutrient exchange economy in terrestrial ecosystems. The tree transfers sugars made during the photosynthesis process, and the fungi transfer minerals and nutrients from the soil, namely phosphorus and nitrogen. The fungi gain these nutrients by decomposing living things in the soil. In times of normal growth, there is an exchange, but in times of stress, the tree can regain sugars it loaned to the fungi. They can also transfer from one tree to another tree, and this is the method by which chemical signals are sent.

 

Trees do not just transfer nutrients between others of the same species. As Suzanne Simard discovered, birch and Douglas fir transfer carbon back and forth through mycorrhizal fungi, with older trees often helping younger trees, more often than not of different species. This mutualistic relationship questions the Darwinian supposition that different species are in constant competition for resources (though mutualism has long been known in nature, and does not challenge evolution). However, this does suggest that forests are perhaps macro organisms, with the various parts (trees and fungi) functioning for the survival of the whole.

 

This is further supported by Simard’s work, which suggests that trees generally allocate their resources to trees more likely to survive in current conditions. For instance, spruce trees passed nutrients to Ponderosa pines (a tree more resilient to climate change), even when young spruces were present). This suggests that, not only are trees cooperating between species, but they may be doing so intelligently.

 

This is a body of research that is far from established, but many of the results are shedding light on aspects of ecology that many could not have before imagined. It is changing, slowly as a tree’s time scale, the belief that trees, or better, forests are passive and unintelligent.

 

Certainly, the idea that trees or forests possess intelligence, self-awareness, consciousness, is a controversial, but not impossible idea. Just because trees do not react in a time frame people can easily observe, does not mean that they do not possess some sort of intelligence… But how, if not through a brain? How do we understand the anatomy of a forest? How do we measure its intelligence? These are all questions for future research.

 
Citations:
http://www.waldwissen.net/wald/baeume_waldpflanzen/oekologie/wsl_mykorrhiza_lebensgemeinschaft/index_EN
https://www.boundless.com/biology/textbooks/boundless-biology-textbook/soil-and-plant-nutrition-31/nutritional-adaptations-of-plants-188/mycorrhizae-the-symbiotic-relationship-between-fungi-and-roots-716-11940/
http://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet

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