Soil and understory plant dynamics during conversion of forest to silvopasture, open pasture, and woodlot

Abstract

Little is known regarding the impact of converting northern hardwood forests to pasture or silvopasture. Our objective was to investigate how understory plant communities and soil physical and chemical properties respond during the first 2 years following conversion of northern hardwood forest to pasture. To accomplish this, we established three forest conversion treatments (silvopasture, open pasture, and woodlot) in a 50 year old northern hardwood forest in New York. The silvopasture and open pasture treatments were seeded with forages and then grazed with cattle after the initial timber harvest. Understory plant inventories and soil sampling were conducted pre-treatment and 2 years after treatment establishment. Understory non-woody plant species richness increased in all treatments during the two year period (F = 73.633, P < 0.001), while species richness of understory woody plants remained similar to pretreatment levels (F = 2.648, P = 0.150). Species most negatively affected by forest conversion included Arisaema triphyllum, Mitchella repens, and Thalictrum pubescens. Species that were only observed after the treatments were established included Danthonia spicata, Agrostis spp., Ranunculus spp., Digitaria spp., Rumex acetosella, and Hieracium spp. One species, Vaccinium angustifolium, was negatively affected by the silvopasture and open pasture treatments, but not the woodlot treatment. Soil bulk density was higher in both the open and silvopasture treatments compared to pretreatment levels, but the woodlot treatment soil bulk density remained statistically similar to pre-treatment levels. Percent total nitrogen, potentially mineralizable nitrogen, and phosphorus increased in silvopastures, open pastures, and woodlot treatment groups compared to pre-treatment levels. Future research should investigate the implications of these changes in ecosystem structure and composition.