Mixed-species plantations: Prospects and challenges

About 2% of English-language literature on plantations deals with mixed-species plantations, but only a tiny proportion (<0.1%) of industrial plantations are polycultures. Small landholders are more innovative, with 12% of Australia's farm forestry plantations under mixed-species plantings, and 80% of Queensland's farm forestry as polycultures. We examine reasons for this discrepancy, and explore the history, silviculture and economics of polycultures. Financial analyses suggest that a yield stimulus of 10%, depending on product and rotation length, may be sufficient to offset increased costs associated with planting and managing a mixed-species plantation, a stimulus that has been demonstrated in many field trials. We conclude that the main obstacle to commercial uptake of polycultures in industrial plantations may be the lack of operational-scale demonstrations coupled with reliable financial analyses.