Mycorrhizae and Oaks

Many trees have a symbiotic relationship with a particular type of mycorrhizae, which is a fungus that grows on or in tree roots. The mycorrhizae extends the root system to collect nutrients and water, which benefits the tree; the tree processes the nutrients and water, which benefits the mycorrhiza, since fungi cannot perform photosynthesis. Oak trees are dependent on two kinds of mycorrhizal fungus:

• Ectomycorrhiza – lives outside the root, in the top four inches of soil, and is visible to the eye.
• Vescicular-Arbuscular mycorrhiza (VA mycorrhiza) – lives outside the roots, in the soil below ectomycorrhiza to 20 feet deep, and is microscopic.

Mycorrhizae filaments, or hyphae, help combat erosion. by holding soil particles in place. Mycorrhizae produces chemicals that help boost the oak tree’s immune system. Other plants in the plant community share in the mycorrhizal grid, enabling resources to be distributed, and thereby ensuring the survival of the plant community as a whole. For more information, see seminar notes by Celeste Wilson: http://www.laspilitas.com/classes/mycorrih.htm.

This video from Iowa State University (http://youtu.be/rPlSkov-xcE) shows endomycorrhizae, where the fungi lives inside the root. Notice the symbiotic relationship at work, here with soy bean mycorrhizae.