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You are here: NRS Home / Research Programs /Forest Disturbance Processes /Climate Change and Events / Effects of CO2 and O3 on the communities of symbiotic fungi associated with aspen and birch roots
Forest Disturbance Processes

Effects of CO2 and O3 on the communities of symbiotic fungi associated with aspen and birch roots

[photo:] A class of symbiotic fungi associated with roots, called mycorrhizal fungi, provide trees with nutrients and water in exchange for sugars.Research Issue

Elevated carbon dioxide (CO2) and ozone (O3) affect tree photosynthesis and growth in largely opposing ways, with CO2 increasing growth and O3 decreasing growth. These changes in growth can affect the amount of carbon going to roots. Associated with roots are a class of symbiotic fungi that provide nutrients and water in exchange for sugars. These fungi, called mycorrhizal fungi, may be sensitive in both abundance and community organization to the changes in trees and ecosystems caused by elevated CO2 and O3. Any changes in these fungi could alter tree nutrition and growth, and alter their ability to reproduce. In addition, the mushrooms formed by these fungi (for example, chanterelles, porcini, matsutake) are important for both wildlife and as non-timber forest products. Therefore, it is important to understand whether pollution affects mushroom production and community composition.

Our Research

We used an existing facility, the AspenFACE site, to examine the individual and combined effects of these gases on mushroom production and community structure, and on the composition and structure of these communities on the roots of trees.  We found that mushroom production increases in response to elevated CO2 and declines in response to elevated O3. Interestingly, elevated CO2 seems to reduce or eliminate the negative effect of O3 on mushroom production more than expected by an additive model. Mushroom community composition was also affected. The most obvious effect appears to be an increase in the abundance of Leccinum mushrooms with elevated CO2 and a decline with elevated O3. Some other species appear to be less affected by elevated O3. We are still in the process of analyzing the community response on roots.

Expected Outcomes

The changes in mushroom production and species composition of the mushroom community mean that elevated CO2 and O3 have the potential to alter the food available to wildlife, and the mushrooms available for harvest. As mushrooms are a very important non-timber forest product, changes in availability of mushrooms will affect economies, especially in the Pacific Northwest. The decline in the production of large bolete sporocarps in response to O3 is of particular concern because boletes are a significant part of the mushroom production and harvest in many regions. This information will be useful in understanding the impacts of changing atmospheric chemistry on natural ecosystems and economies.

Research Participants

Principal Investigator

Research Partners

  • Carrie Andrew, Michigan Technological University

Last Modified: 07/24/2009