Trees
The forest is more than the sum of its trees. ~ Swiss botanist Christian Körner
Forests are a hotbed of competition, as saplings struggle for enough light to make their way to the canopy. This belies a congeniality that goes on belowground, especially among mature trees.
Up to 40% of the carbon in the fine roots of one individual may be derived from photosynthetic products of a neighbor. ~ Swiss botanist Tamir Klein et al
Mycorrhizae have an interest in keeping the guild above them healthy, so they allocate their surplus accordingly.
That 4% of net primary productivity is transferred to neighboring trees suggests that carbon is a nonlimiting resource, and not growth-limiting for large trees. Thus, carbon allocation and loss to mycorrhizal fungi does not necessarily impair plant fitness. The exchange of “nonlimiting” carbon for nutrients may be one of the key factors responsible for the evolutionary stability of the mycorrhizal symbiosis. ~ Dutch evolutionary biologist Marcel van der Heijden
