Root Systems of Individual Plants Worldwide 2022

The above- and below-ground sizes and shapes of plants strongly influence plant competition, community structure, and plant-environment interactions, but the plant size and shape across climate regimes remain incompletely understood. In this study I seek to understand how plant geometries respond to varying climates via trade-offs in shoot height and width, and root depth and spread. I more than doubled the Root Systems of Individual Plants (RSIP) database to contain 5,647 observations, to our knowledge the largest database describing the maximum rooting depth, lateral spread, and shoot size of terrestrial plants in the world. Shoot size and root system size strongly covary. Across climatic gradients woody plants show deeper-narrower root systems in arid climates and taller shoots in humid climates. Phylogeny greatly influences shoot size. Rooting depth is primarily influenced by climate seasonality and lateral root spread is strongly influenced by shoot size. Using our newly expanded global database I found that shoot size covaries strongly with rooting system size; however, these relationships are not static across the climate space, as the geometries of plants shift considerably.