Industrial Ecology is an industrial environmental management concept with an analogy in the natural ecosystem. In an ecosystem, materials are recycled between organisms, and energy is embedded in the matter of the food chain, while the only external input to the system as a whole is the solar energy. An Industrial Ecosystem is a system where the industrial actors use this natural recycling model and co-operate by using each other's waste material and waste energy flows to minimize the system virgin material and energy input as well as the waste and emission output from the system as a whole. In theory, the economic environment win–win can be achieved as raw material, emission control and waste management costs are reduced through using waste as a resource of production. In this paper, the material and energy flows of the forest ecosystem are considered, and this natural recycling model is used to construct an industrial ecosystem in the forest industry of Finland. Recycling of matter including nutrients and carbon constitutes the basis in the operation of the forest ecosystem as well as in the operation of the forest industry system. The forest industry will use the cycle in these flows as a source of raw materials and energy. An industrial ecosystem is constructed with the flows of matter, nutrients, energy and carbon.