Copyright 2018 Accademia dei Georgofili
A short review on the ancient question between mechanicism against organicism applied to sylviculture and vegetation science. The mechanicalist idea of the forest stand as a collection of plants, each independent in his ecology and settled in the site following different ways and arrived in different times, suggest the possibility to apply a sylviculture based on planting the most rentable species. On the contrary the conception of a plant community with trees related each other by organic bonds suggest the idea of a nature-close sylviculture based on uneven aged mixed stands. Generoso PATRONE professor in Florence, designed the mechanicistic idea as “classic” and the organicistic one as “romantic”; the first based on planning against, the other supporting management based on intuition and experience. The principles of a nature-close sylviculture were notoriuosly pacticed in Switzerland by Henry BIOLLEY who conceived the forest stand like a family of trees. Following the german Alfred MOELLER the forest stand as an organism, the various tree and undergrowth layers are similar to organs and every tree plays the role of a cell. In the field of plant ecology Friederick CLEMENTS is still the leading figure. He developed one of the most influential theories of vegetation development. Vegetation cover does not represent a permanent condition but gradually changes over time. Clements suggested that the development of vegetation can be understood as a sequence of stages resembling the development of an individual organism. Clements’s climax theory of vegetation dominated plant ecology during the first decades of the twentieth century. At present, despite strong criticism, significant Clementsian trends are re-emerging. Among the most remowned italian botanists Giovanni NEGRI stated that a plant community is a collection of individuals incidentally settled together as a consequence of similar ecological requirements and as result of competition vicissitudes. Valerio GIACOMINI agreeds that a plant community can not be compared with an organism, but the definition of Negrii appears too restrictive. Alberto CHIARUGI, on the basis of studies on the postglacial vegetation vicissitudes enphasizes the migratig character of plant species. Sir Arthur TANSLEY reluctantely drops the similarity of plant community with an organism because the term is currently referred to single individuals. His aim was then to draw attention to the interactions between the biological components of the community and their environment. He defined the ecosystem as the whole system, including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment. He also insisted that, «Though the organisms may claim our prime interest, when we are trying to think fundamentally, we cannot separate them from their special environments, with which they form one physical system». Later the concept of ecosystem bounced on the more general complex system. A complex system is a system composed of many components which may interact with each other. In many cases it is useful to represent such a system as a network where the nodes represent the components and the links their interactions. Examples of complex systems are Earth’s global climate, organisms, the human brain, social and economic organizations (like cities), an ecosystem, a living cell, and ultimately the entire universe. Following the french philosopher Edgar MORIN a complex system is alike to an organism; so we go back to the origin of the question. The well known cinema director Michael Crichton observes that humanity had allways tried to manage complex systems without any attempt to understand them; and sometimes even with good results.
