One of the challenges in ecology is to understand how macroscopic patterns of ecological systems emerge from interactions between individual organisms. The Perfect Plasticity Approximation (PPA) is a recently developed model predicting the stand-level forest dynamics by scaling up individual-level processes (Strigul et al., 2008, Ecological monographs 78:623-545). In particular, the PPA offers good predictions for 1) stand-level attributes, such as basal area, tree density, and size distributions; 2) biomass dynamics and self-thinning; and 3) ecological patterns, such as succession, invasion, and coexistence. The model includes the system of von Foerster partial differential equations and an integral equation (the PPA equation). The PPA model is both analytically tractable and computationally simple.
Results/Conclusions
Here I present a novel model, called Matreshka (after the Russian nesting doll), for scaling from individual-level to the landscape level. The Matreshka model employs the PPA model as an intermediate step of scaling from the individual level to the forest stand-level (or patch-level). At the next step of scaling age-structured dynamics of forest stands (patches) for one soil type is described by another von Foerster equation using a model developed by Levin and Paine (PNAS 1974, 7: 2744-2747). Finally, another equation is used to model the forest dynamics on different soil types. The Matreshka model is analytically tractable and can be presented as a continuous or discrete model. This presentation will demonstrate how to estimate forest-level attributes, such as basal area, tree density, and size distributions of trees across different stand-ages and soil types. The current efforts are focused on estimating the model parameters and its validation using forest inventory (FIA) data.
