The starting point for our work are (models for) forest ecosystems. We seek to integrate two sources of knowledge about such ecosystems: the scientific approach from the viewpoint of an exo-observer (one that is detached from the system and has theoretically unlimited observational capacity) and the management approach for utilization (one that has a common history with the managed system and includes the possibility of an endo-observer). Within the scientific approach, these ecosystems are often regarded as being among the most "complex" systems that can be abstracted as objects, whereas their practical management for human utilization (including interferences of an occasionally entangled endo-observer) sometimes has allowed economically reliable predictions over time scales from years up to a century. Each approach alone seems to be insufficient to solve the theoretical and applied problems of contemporary ecology. Practical experiences on one hand cannot be extrapolated and become i...