Rationale Plant physiology drives terrestrial ecosystem responses to global climate change. All plants store energy via sugars and starch, providing important survival strategies by buffering asynchrony in metabolism and photosynthesis. Stored carbohydrates represent a large carbon pool and flux in forest. Measurements suggest that sugar and starch accounts for 5 – 20% of forest carbon and fluctuate seasonally by up to 5 – 10%. Despite the magnitude, many models ignore or oversimplify storage dynamics. Improving a theoretical framework for stored carbohydrate dynamics aids predictions about forest responses to climate change and disturbances.
Framework We apply dynamic optimization to plant physiology, hypothesizing that allocation to storage maximizes lifetime expected reproduction. Our framework formalizes the microeconomics analogy of resource budgeting. Using Pontryagin's maximum principle, we study properties of optimal solutions to describe allocation and storage.
Takeaway Optimization implies active storage regulation, ontogenetic and phenological differences, and environmental hysteresis in allocation. Life history differences produced different seasonal dynamics in simple models. The max principle implies latent variables which may correspond to physiological mechanisms, bridging the gap between optimization and mechanisms.