Of the NPP allocated belowground, the proportion allocated
to large structural roots is about 25% of the NPP allocated to
stem wood. The remainder is available for fine roots and mycorrhizae.
Although carbon allocation patterns are relatively well known
for most structural and functional components of tree growth and
metabolism, the allocation and use of NPP among fine roots and
mycorrhizae is not yet well quantified. Likewise we have little
information about how EM fungi compete for arboreal carbohydrates
or how various species of EM fungi allocate acquired carbon to
growth, metabolism, function, or the production of sporocarps.
Because so little quantitative information exists about carbon
allocation in this realm, we start with two simplifying assumptions:
(Photograph by Eric Danell)
(Photograph by Charles Lefevre)