Acknowledgments The authors would like to thank the United States Department of Agriculture National Agroforestry Center for their sponsorship of this project (project
number: USDA, National Agroforestry Center, Lincoln, Nebraska: 4124–4521–48–3209). We would also like to thank Bruce Wight, Lead Agroforester with the National Agroforestry Center and Jan Thompson, Department of Natural Resource Ecology and Management, Iowa State University for their helpful comments.