Larsen (1980) describes the mosses in the boreal forest
as growing vigorously, using nutrients that they receive in
throughfall, and Weetman (1968) likewise found that
feather mosses in a black spruce (Picea mariana) forest
relied on dust and precipitation for both nutrients and
moisture. Tamm (1953, 1964) found that rainwater was
sufficient to account for all the nutrients needed by the
pleurocarpous Hylocomium splendens. Weetman and
Timmer (1967) concluded the same thing for Pleurozium
schreberi in the black spruce forest, where N, K, Ca, and
Mg leached from the canopy. This canopy throughfall
source annually supplied 9 kg of N per hectare to the moss.
In fact, the spruce trees are known to be N-deficient and
root prolifically at the base of the green layer of mosses