Restoring a prairie: Testing effectiveness of Chinese tallow tree (Sapium sebiferum) mulch to reduce seedling emergence

Abstract

The invasive Chinese tallow tree (Sapium sebiferum) is difficult to control because of its large seed bank and ability to resprout from cut stumps. I performed laboratory and field experiments to evaluate the effectiveness of mulching live trees for restoring invaded prairies. Herbicide use was limited to manual application to cut stumps. I manipulated mulch depths and types in the field and measured soil temperatures beneath them. At depths of as little as 5 cm, Sapium mulch damped soil temperature fluctuations and reduced seedling emergence. Reduced seedling emergence was not the result of allelopathic compounds in Sapium mulch because other mulch types suppressed emergence similarly. Substantial regrowth of native vegetation occurred through the mulch. Independent manipulations of mulch depth and temperature fluctuations in a lab experiment confirmed that mulch suppressed seed germination indirectly via soil temperature effects. This prairie site can now be managed by mowing or burning.