Ecohydrological effects of forest conversion to pasture and silvopasture in New England
H. Asbjornsen, A. Coble, K. Jennings, M. Vadeboncoeur
in collaboration with Rich Smith, Alix Contasta, and others.
Much of the current land in New England suitable for agriculture is currently under secondary forest cover. Many farmers in New England are clearing or thinning forested lands to expand existing agricultural fields in order reclaim land that was used for agriculture prior to the early 1900s and to meet the consumer demands for locally produced agricultural goods. Clear-cutting portions of the forest is one approach to expand existing agricultural lands. However, there is a growing interest in agroforestry practices such as silvopasture, which is the simultaneous management of livestock grazing and trees on the same land.
The goal of the study is to identify the effects of forest-to-agriculture conversion (clear-cut and silvopasture) on ecosystems services such as nutrient retention and water regulation and balance, as well as effects on provisioning services such as forage crop yield on farms across three states (MA, NH, and VT) in New England. We worked with farmers across the three states to develop monitoring sites at five farms where forest-to-pasture and forest-to-silvopasture will be implemented. Forest-to-agriculture conversion plots across the three states were complemented with an experimental conversion study at the UNH Organic Dairy Research Farm (ODRF) in Lee, NH.
The UNH ODRF site includes an established pasture, converted open pasture, converted silvopasture, and a reference intact forest stand (see aerial image below and photos at left). After conversion of forest plots to pasture and silvopasture in 2015, our lab led measurements of tree growth and tree water use in the reference and silvopasture plots. We also measured soil hydraulic properties and precipitation throughfall in order to better undersand the hydroligic effects of of forest-to-agriculture conversions in the northeast.
This work was funded by USDA-AFRI.
A number of publications are in preparation based on this project. So far these have been led by our lab:
Coble AP, Contosta AR, Smith RG, Siegert NW, Vadeboncoeur MA, Jennings KA, Stewart AJ, Asbjornsen H. 2020. Influence of forest-to-silvopasture conversion and drought on components of evapotranspiration. Agriculture, Ecosystems and Environment, 295: 106916. doi:10.1016/j.agee.2020.106916 [PDF available from USFS]
Stewart AJ. 2017. Land use change in the northeast united states: retaining forest structure and its soil hydraulic properties through silvopasture. M.Sc. thesis, University of New Hampshire. http://scholars.unh.edu/thesis/1125
Asbjornsen A, Coble A, Contosta A, Jennings KA, Orefice J, Smith R, Steward A, Vadeboncoeur MA. Silcopasture: A climate-friendly alternative to conventioal open pasture practices. INSPIRED, Winter 2023. https://colsa.unh.edu/research/briefs/silvopasture-climate-friendly-alternative-pasture-practices