Trees share sugar with each other through root and fungal connections

Wohlleben describes observing tree stumps in his forest that, though cut down decades earlier and lacking leaves to photosynthesize, remained alive at the edges — their tissue still green and functional — evidence that neighboring living trees were feeding them sugar through connected root systems, keeping the stump alive long after it should have died on its own.

He explains that tree roots frequently graft directly onto neighboring roots of the same species, and separately connect indirectly through shared mycorrhizal fungal networks in the soil, both providing physical pathways through which sugars, water, and nutrients can move between individual trees, sometimes even across species.

Wohlleben frames this resource-sharing as evidence that trees in an intact forest behave less like isolated competitors and more like members of an interdependent community, where a stronger, healthier tree can help sustain a weaker or damaged neighbor — though he acknowledges the underlying motivations, to the extent trees can be said to have any, remain the subject of ongoing scientific interpretation.

Takeaway: a felled tree stump can stay alive for decades, kept going by sugar shared through the roots of trees still standing around it.