STANDSIM – a general model for simulating the growth of evenaged stands.  J.E. Opie.  November 1971.  31 pp. (unpubl.)

SUMMARY

STANDSIM is a Fortran-coded program for simulating the growth and yield of an evenaged monospecific stand. It is assumed that tree spacing is at all times fairly even. Any site quality and practically any treatment (initial density by thinning regime) that satisfies the spacing assumption can be examined. There are 16 specific functions signposted in the listing. By altering only these, it should be possible to approximate the growth of any tree species. Feedback to progressively improve accuracy should be also be directed at these 16 specific functions.

STANDSIM is a non-stochastic empirical model which “grows” the individual trees on an annual or periodic (up to five years) cycle, integrating the tree data so as to obtain stand data in considerable detail. Inputs can refer to either proposed or existing stands. For proposed stands the main inputs are the thinning regimes, site index, rotation and initial density as number of seedlings per acre. For existing stands most of the input is as above, except that the starting density and structure can be specified in much detail if so desired. The output, given on an annual or periodic cycle, is comprehensive in respect of the live stand, mortality, thinnings and total production.

This report describes the main aspects of the model, giving emphasis to the 16 specific functions. The results of tests with Eucalyptus regnans are given. The paper concludes with a discussion of the applications, present limitations, and proposed developments. The listing and samples of input and output are also provided.

Also published:

Opie, J.E. (1970)  STANDSIM – a general model for simulating the growth of evenaged stands.  Proc. 3^rd Conf. Advis. Group of For. Stat., IUFRO Sect. 25, France, 1970, pp. 217-40.