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

Abstract

Rhododendron maximum L. restricts regeneration of overstory species; however, the mechanisms are poorly understood. Three treatments were used to examine the effects of R. maximum 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 ( 2 x that observed under shadecloth, while percent germination and survival in R. maximum plots were lower than in either of the other treatments throughout the sampling period. These results suggest that in addition to the light limitation associated with R. maximum, edaphic effects such as low soil moisture or allelopathic compounds may inhibit Acer rubrum success.