Figure 6.10 The plot shows the result by Debeljak (2001). He examined managed a virgin forest in different stages. Gap has no trees, while the virgin forest changes from optimum to mix to regeneration and back to optimum, although the virgin forest can be destroyed by catastrophic events as fire or storms. The juvenile stage is a development between the gap and the optimum. Pasture is included for comparison.

cycle" and it is shown that the ecosystem is moving toward a higher specific exergy (and biomass if possible, as growth of biomass is dependent on the available amount of the limiting element), if the inorganic components are available to form more biomass for each cycle.

Five of the presented hypotheses to describe ecosystem growth and development, are examined with respect to three growth forms, excluding the boundary growth:

A. Entropy production tends to be minimum (proposed by Prigogine (1947, 1955, 1980) for linear systems at steady non-equilibrium state, not very far from thermodynamic equilibrium systems). Mauersberger (1981, 1983, 1995) applied this to derive expressions for bioprocesses at a stable stationary state (see also Chapter 2). Reduction of the entropy production means that the energy utilization is increased, which is obtained by an increased cycling of the energy and reduced loss of energy to the environment, or expressed differently: the retention time of a given portion of energy in the system is increased.

B. Natural selection tends to maximize the energy flux through the system, so far as compatible with the constraints to which the system is subject (H.T. Odum, 1983). This is the maximum power principle (see Section 6.4).

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