Improving understanding on forest functions under climate change and management with modular process-based model pyAPES v1.0

Forests are under high pressure due to anthropogenic activity and climate change. Understanding how these phenomena influence soil-plant-atmosphere continuum is important for ensuring sustainable management now and in the future. Process-based modelling combined with data assimilation enables developing a comprehensive understanding on how individual processes influence ecosystems and services they provide. Such approaches are essential for capturing the complexity of interactions that govern water, carbon and energy fluxes across spatial and temporal scales.

pyAPES is a multi-layer, multi-species process-based model designed to simulate the soil-plant-atmosphere continuum. It enables analysis of how changes in environmental conditions, plant traits, or stand structure influence microclimate, leaf gas exchange and ecosystem level fluxes. Over the past decade pyAPES has been widely applied in studies investigating how anthropogenic activity and climate variability affect forest processes at multiple scales. Recent developments have greatly improved model usability, making it a versatile and accessible tool for addressing emerging research questions on ecosystem functions.

In this work, we present recent advances in pyAPES that enhance usability and extend capabilities for simulating forest ecosystem processes. We demonstrate pyAPES applications at experimental sites, exploring how forest management and climate change influence stand microclimate, water transport and carbon fluxes. We also show how the modular architecture lets researchers tailor the model for their research needs without the need to learn or execute the full model and how accessible code, documentation and tutorials support practical implementation.