Mother Trees Recognize Their Young and Feed Them More

In one Douglas fir forest in British Columbia, researchers found that a big old mother tree can recognize her own seedlings in the understory, and she feeds them more than she feeds strangers.

Suzanne Simard, a forest scientist who studies those forests, found that the biggest, oldest trees sit at the center of underground webs made by fungal threads that join with tree roots. In that partnership, the fungus gathers water and nutrients from the soil and trades them for carbon, the food trees make through photosynthesis, and carbon moves through those threads from tree to tree.

The team grew related and unrelated seedlings near one mother and traced labeled carbon, using rare forms called isotopes, into each seedling. A mother sent measurably more to her kin than to unrelated seedlings nearby.

If the mother is injured, Simard said, "she sends even more carbon to her kin seedlings," as though "she's passing her energy, her legacy, to the next generation."