Abstract
The growth process in a pure even-aged closed stand is described synthetically in terms of stand growth and tree growth. First, the following assumptions were made: (1) The maintenance respiration rate in a stem is proportional to 2/3 power of its volume, and the construction respiration rate in a stem is proportional to the growth rate of its volume; (2) In a stand, the net photosynthesis rate in a tree is proportional to the n-th power of its stem volume, where n is a positive real number, and the distribution ratio of surplus production in leaves to stems is constant; (3) In closed stands, the net photosynthesis rate per unit is constant, and it is dependent only on species and site. On the basis of these assumptions, growth equations for stand volume V and tree volume v were derived as follows: dV/dt=A-bΣv2/3, dv/dt=(4/Σvn)vn-bv2/3 where A is a constant dependent on species and site and b is a constant dependent on species in a region. Next, values of parameters were estimated for plantations of sugi (Cryptomeria japonica D. DON) and hinoki (Chanuzecyparis obtusa (SIEB. et ZUCC.) ENDL. Most of estimated values of parameter n ranged from 0.9 to 1.1. Finally, the assumptions and values of parameters involved in the model are discussed.
