Control of Hay-Scented Fern by Mowing

Abstract

Abstract Hay-scented fern (Dennstaedtia punctilobula) is a native species that can invade and dominate the forest understory, after thinning and intensive deer browsing. Fern colonies form a dense cover 60 to 80 cm high that intercepts light and inhibits tree seedling regeneration. Hay-scented fern can be controlled with herbicides, but some landowners (both public and private) seek alternative methods. We investigated mowing as a possible method of fern control. We tested different mowing schedules and measured the response of ferns (frond length and density) and of natural regeneration and planted seedlings. Mowing the ferns twice in one growing season (first in June when the fern fronds had reached their full height and again in August) led to a significant reduction in frond length during the next two growing seasons compared to untreated controls. Mowing four times over 2 years reduced both length and density of ferns. Mean density of naturally established tree seedlings was four times greater on these treatment plots compared to controls, but with great variability among plots. Red oak (Quercus rubra) and sugar maple (Acer saccharum) seedlings planted the year after mowing showed greater survival and height growth compared to controls.