The land-surface components of several Earth System Models (ESMs) have the capacity to represent the size and composition structure of terrestrial plants (FATES, ED2, SEIB-DGVM, LPJ-GUESS, Ent, etc). While these model frameworks are designed to be able to simulate the allocation and transport of nutrients in size-structured terrestrial vegetation, our understanding of these processes are not as well understood.

Here we present a model framework that enables the testing and intercomparison of different hypotheses for nutrient allocation and transport in plants. This framework, called the Plant Allocation and Reactive Transport Extensible Hypotheses (PARTEH), is designed with an emphasis on modularity and extensibility to facilitate the addition and comparison of new hypotheses. This framework is currently a component of the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), yet it is designed to be readily integrated into other terrestrial ecosystem simulators by making use of a light-weight software interface. Here we use PARTEH to evaluate the sensitivity of vegetation growth to different allocation hypotheses; including using flexible versus fixed stoichiometry in plant organs, variable capacity for carbon and nutrient retranslocation, and different prioritization across organs for replacing carbon and nutrient turnover.