There are the natural processes, flows and chains, making life possible for the components and communities of the ecosystem, forest or city alike. It is wise to diagnose and know them, because they give insight in the way the ecosystem has built up its resilience and diversity leading to understanding the state of it.
The main natural cycles are related to energy (flow), nutrients and water (cycles). And there are man-made processes related to the governance of the city, such as among others that of democracy, finance, strategy and policy.

Democracy, © Civitas Naturalis
They all relate to the core of public life, to resources, essentials and effects of decision making and city management. Cycles and flows are essential in every ecosystem.
- Water is the key source for life because all humans and communities need it. The cycle can be that of condensation – precipitation – collection – evaporation. But due to human and urban use the cycle has many variants.
- Energy is key in all what we do. The main cycle is that of energy (solar) – production – fixation (plants) – consumption. Also here there are refinements, but it is good to know that we, inhabitants of the earth are part of the empire of the sun. All life begins here.
- Nutrient movement includes that of carbon, sulfur, nitrogen, phosphorus, oxygen that continually recycle along with other mineral nutrients: production – allocation – consumption – decomposition. Due to our industrial process, the travels of nutrient can be complex and long before the cycle closes.