Worldwide, the footprint of agriculture is higher than that of any other land use, making the local decisions of millions of farmers a global force for achieving the maintenance of ecosystem services. Biodiversity offsets are increasingly used to attempt to reconcile conflicts between production and conservation. Offset policies operate on the principle of habitat substitutability, but little work has considered whether those targeted by such policies perceive nature that way. For instance, do landholders perceive trees of different arrangements, ages or species to be interchangeable? We used a large-scale landholder survey to understand how graziers manage their farm trees, and whether their beliefs are amenable to substitution. Three natural clusters were found, that: (A) liked a tidy farm but did not differentiate trees by species, age or arrangement; (B) strongly supported the need for diversity in tree cover; and, (C) preferred woodlands and connective strips to sparse trees. Those positions were consistent with their beliefs about the costs and benefits of different arrangements of trees, but were largely inconsistent with their declared tree planting and protection activities. Tree management activities were more easily explained by commodity (pro-woodland graziers (C) were most likely to be cropping) or by career stage and what that meant for time and money resources to do conservation work (contrasting A and B). Offset policies and policy incentives encouraging vegetative heterogeneity would motivate at least these first two clusters, helping to sustain a diversity of tree cover and thus ecosystem services on farms.