Agroforestry Land-use Economic Yield and Risk (ALLEY) Model 2.0: a computer suite to simulate and compare stochastic yield and returns of alley crop, monocrop, and pine plantation systems in the U.S. South.
Alley crop systems, which combine field crops in wide alleys between rows of trees, have been presented as a sustainable land use that can generate economic benefits and ecosystem services. We created models of stochastic processes that simulate yields, prices, and costs for an alley crop system and two competing land uses: monocrop and pine plantation. The suite of models, called Agroforestry Land-use Economic Yield and Risk (ALLEY) Model 2.0, uses a Monte Carlo approach, iterating numerous times over a given time horizon, to estimate and compare expected values and distributions of potential financial returns from the three land uses with selected management variables. ALLEY Model 2.0 includes sample historical data on crop yields in Halifax County, NC, crop and timber prices in North Carolina, and costs from the U.S. Southeast. Timber growth and yield were simulated using biometric equations from past research on loblolly pine in the U.S. Southeast. Other parameters with little historical data, such as competition between trees and annual row crops in alleys, were based on literature review and authors’ estimates. ALLEY Model 2.0 may be used for research on agroforestry decision making, testing of crop characteristics that improve returns in agroforestry settings, evaluation of current policies and future policy options, or assessment of potential changes in returns due to the effects of a changing climate. An example application is provided. The ALLEY Model 2.0 software suite and sample data file can be accessed at https://www.srs.fs.usda.gov/pubs/gtr/gtr_srs235/.