Effects of 'Rhododendron maximum' L. on 'Acer rubrum' L. Seedling Establishment

摘要

Rhododendron maximum L. restricts regeneration of overstory species; however, themechanisms are poorly understood. Three treatments were used to examine the effects of R. maxium germination success and survival of Acer rubrum L. under a closed overstory canopy: (1) R. maximum understory, (2) open understory, and (3) open understory with shadecloth. Shadecloth treatments mimicked the low light conditions beneath R. maximum (<5% full sun) while controlling for R. maximum forest floor influences. Soli moisture was significantly lower under R. maximum than under open or shadecloth treatments. Initially, Acer rubrum survival and similar for open understory and shadecloth treatments, while germination and survival in R. maxmium plots were low. After approximately 20 d, mortality in the shadecloth treatment increased and survival rates were less than 5% by the end of the sampling period.