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Functions and growth parameters

All functions contained in section 3 are interpreted as strings and translated to mathematical expression by the Java Mathematical Expression Parser (JMEP) internally. First Shugart's optimum growth function for individual trees (Shugart 1984) is given in item 3.1. As you can see, the function includes various parameters whtich are assigned to values for each sepcies in the growth parameters section 4. It further includes a repetition of the parabolic height function (commpare item 3.2). The only state variable which the growth function relies upon is d, i.e. a shorthand for the diameter at breast height. The crown dimensions are defined by allometric (power-law) functions (items 3.3, 3.4). Since the assumption is made that crown height and crown width grow isometrically, the two allometric relastionships entail the same set of parameters.
Please note that the two parameters for simulating the salt effect on growth (i.e. useg, dseg) are not yet made effective.