Fungi cannot produce sugars, though they need them for fuel just like trees do

From there, sugar flows down to the roots.Mycorrhizal fungi encounter the tips of the roots and either surround or penetrate the outer root cells,depending on the type of fungi.Fungi cannot produce sugars, though they need them for fuel just like trees do.They can, however,collect nutrients from the soil much more efficiently than tree roots—and pass these nutrients into the tree roots.In general,substances flow from where they are more abundant to where they are less abundant,or from source to sink.