Growth form
Species were coded as trees, shrubs, or non-woody plants. Trees included woody plants >10m tall, typically with a single trunk coming from the base. Shrubs included upright woody plants <10 m tall, typically with one or several trunks coming from the base. We also included in the shrub category hemi-parasites and hemi-epiphytes. Non-woody plants included herbs, epiphytes, and non-woody climbers. Growth form of species was often linked to habitat in that many non-woody plants and shrubs occurred in the forest understory, while many trees occurred in the subcanopy and canopy. However, non-woody plants, shrubs, and trees also occurred in open habitats like prairies. We did not include habitat as an additional predictor in our models due to its high collinearity with growth form.