Document: SAR-3-64-1

Experimental removal of invasive Acer platanoides seedlings and canopy trees: Responses of native Acer saccharum and invasive Acer platanoides seedling banks.

PENDERGAST IV, T.H.* ¹, M.E.DWYER ^1,2, S.R.PASSAFARO ¹ and S.L.WEBB ¹

Drew University, Madison NJ 07940 ¹
Natural Resources Group, New York NY 10029 ²

Abstract:
Norway maple (Acer platanoides) is an invasive tree of major concern in northern New Jersey forest fragments. To probe the dynamics of the Norway maple seedling bank, and to test the efficacy of restoration strategies, trees and seedlings of this invasive tree were removed in 1997 from a mixed maple forest. Treatments removed trees (height > 1.5 m) and seedlings (height < 1.5 m) in a crossed design with a total of 80 permanent plots, all sampled before removals and two years later. The forest floor was initially a 50:50 carpet of sugar maple and Norway maple seedlings. After two years, removal of Norway maple trees caused a significant reduction in recruitment of new Norway maple seedlings but caused a positive response by native sugar maple (Acer saccharum), specifically a pulse of new seedlings in the first year following removals. Conversely, the removal of Norway maple seedlings initiated far more new Norway maple than sugar maple seedlings. Sugar maple densities did not increase over those in non-removal areas, but new Norway maple recruitment was significant, though not sufficient to completely replenish the removed seedling bank within two years. Although removal of canopy trees appears effective as a restoration tool, other invasive species (especially Lonicera japonica, Alliaria petiolata, Robinia psuedo-acacia) proliferated alongside sugar maple where tree removals opened up the canopy. Restoring the pre-invasion community will thus require ongoing intervention in the future.

Keywords: biological invasion, restoration, Acer platanoides

This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS