Litterfall, growth, and turnover of arboreal lichens after partial cutting in an Engelmann spruce - subalpine fir forest in north-central British Columbia

Dynamics of canopy lichens were investigated for 2 years after group and single-tree selection harvesting in a Picea engelmannii Parry ex Engelm. - Abies lasiocarpa (Hook.) Nutt. forest in north-central British Columbia. Litter fall was collected in 1-m(2) traps set on the forest floor and estimates of Alectoria sarmentosa (Ach.) Ach. and Bryoria spp. litterfall adjusted for decomposition in the snowpack. Growth rates of A. sarmentosa and Bryoria fuscescens (Gyeln.) Brodo & D. Hawksworth were measured by repeatedly weighing samples maintained in mesh enclosures in the canopy. Standing crop of canopy lichens was measured in concurrent studies. There appeared to be a small postharvest pulse of litterfall in the single-tree selection area, but it was largely masked by natural variation. Ninety percent of the lichen litterfall was deposited within 10 m of the nearest tree. Annual relative growth rates of A. sarmentosa and B. fuscescens ranged from 2.7% to 10.4% and from 2.4% to 9.1%, respectively. Growth rates of both species were as high in the single-tree selection area as in the unlogged control area but were reduced along the edges of group selection openings. Growth and turnover (annual litterfall as a percentage of standing crop) of Alectoria were approximately in balance, but growth of Bryoria exceeded turnover. In situ decomposition of Bryoria may account for the difference.