Effects of litter, soil surface conditions, and microhabitat on Cercocarpus ledifolius Nutt.: Seedling emergence and establishment

We assessed the effects of the litter layer, soil surface conditions, and microhabitat on emergence of the tree Cercocarpus ledifolius, and how litter affected establishment and survival of first year seedlings of this species. Natural seedling emergence was similar in three microhabitats: open interspaces (0.12 kg litter m(-2)), beneath Artemisia tridentata canopies (0.27 kg litter m(-2)), and beneath C. ledifolius canopies (2.5 kg litter m(-2)). However, because seed dispersal is highest under trees, and lowest in the open, seedling emergence seemed to vary and have highest values in open interspaces. Emergence rates did not vary between soil surface treatments, but were lower in experimental litter treatments than in treatments, without litter, independent of microhabitat. In contrast, litter beneath trees favored subsequent seedling establishment and survival. This study shows that the role of the litter layer varies during the first year of the life of this species, with litter inhibiting initial emergence but enhancing early seedling survival. (C) 2002 Elsevier Science Ltd.