Moss carpets raise mycorrhizal density and enable phosphorous circulation between canopy and soil

Evidence

Beneath them in the humus live the mycorrhizae, a group of fungi which live symbiotically with the roots of trees. The term literally means fungus (myco-) root (-rhizae). The trees host these fungi, feeding them the sugars of photosynthesis. In return, the fungi extend their filamentous mycelium out into the soil to scavenge nutrients for the tree. The vigor of many trees is completely dependent on this congenial relationship. It has recently been discovered that the density of mycorrhizae is significantly higher under a layer of mosses. Bare soil is far less hospitable to this partnership. The association of moss and mycorrhizae may be due to the even moisture and nutrient reservoir beneath the moss carpet. Studying the interactions that happen belowground, among microscopic beings, is notoriously difficult, but a group of researchers has untangled an intricate three-way connection. Tracing the flow of phosphorous through a forest, they followed its footprints in a convoluted path that started with the rain. Throughfall washed phosphorous from the spruce needles onto the mosses below, where it was stored until mycorrhizal fungi insinuated their filaments into the moss turf. Their threadlike hyphae and extracellular enzymes absorbed phosphorous from the dead tissue of mosses. These very same fungi with hyphae in the moss also had hyphae in the roots of the spruce, forming a bridge between moss and tree. This web of reciprocity ensures that phosphorous is endlessly recycled, nothing wasted. — Robin Wall Kimmerer, Gathering Moss, 593

Categorization

• XREF: The moss-mycorrhizae-tree bridge is the finest-spatial-scale nutrient-cycle close-read the polyad’s observation method aspires to. — connects to: Mosses generate the humidity that sustains the entire rain forest food web — Robin Wall Kimmerer, Gathering Moss: A Natural and Cultural…, 582; Hidden mycorrhizal networks allow logged or burned forests to regrow — Jamal Awil, The Whispering Archive: The Complete…, 1683
• ADDENDUM: Supports the trees-as-infrastructure article’s root-graft and connection themes with a three-way nutrient-link mechanism.

Broader Connections

• Hidden mycorrhizal networks allow logged or burned forests to regrow #expands (0.75) — Jamal Awil, The Whispering Archive, 1683