In terrestrial environments, forests are dominated by plants which structure the landscape, offering habitat to thousands of species. Forests exist also in the ocean, and they are dominated by sessile benthic organisms (such as sponges, corals, bryozoans) which form three-dimensional structures providing architectural complexity and sheltering, feeding, protection for diverse associated biota. These communities are similar to terrestrial forests, with the main difference that they are dominated by animals instead of plants. The term marine animal forest (MAF) has been proposed to define those animals dominated three dimensional communities which are present all over the world, from polar to tropical regions and from shallow to deep. In terrestrial ecosystems, forest are characterized by high associate biodiversity and stable climatic conditions (microclimate). The presence of a microclimate, the role played by forest three dimensionality in supporting biodiversity and have been hypothesized also for MAFs. Nonetheless, their capability to support those ecological functions and therefore to deliver the above cited ecosystem services is still undefined. Even more unknown, because never quantified and demonstrated yet, is the existence of a relationship between forest density and structure and such capability. The seminar will present the current knowledge on the functional ecology of these habitats and their resilience capacity.