During the last two years a calculation program has been developed by the Department of Silviculture at Joensuu Research Station, in cooperation with the Association of Private Forestry, for comparing different forest regeneration alternatives in the most common practical regeneration situations in South-Finland. The aim has been to combine biological information concerning forest regeneration with the cost of the regeneration stage and the future value and wood production capacity of the young stand. The main emphasis has initially centered on the comparison of the different artificial regeneration alternatives. The main details of the calculation program for comparing the different alternatives in both artificial and natural regeneration and some illustrative examples from dry mineral soil sites (Vaccinium-type) in South-Finland are presented in this article. The calculation program has been designed for use by a computer. The basic premise in the program is to obtain, at minimum costs, a viable stand which fulfils certain minimum of requirements. The program can be divided into two basic parts: - the model containing certain calculation stages and rules, - the decision-maker feeds in certain types of basic information, i.e. he defines the site type data and can, if desired determine the outcome of the calculation by entering the information (e.g. costs) or instructions (e.g. scrub control methods) which best correspond to the conditions in question. The calculation program includes the following groups of individual factors: 1. The so-called decision tree in each of the different regeneration cases. The decision tree is a description of the measures and alternatives in the different stages within the regeneration period. It includes an assessment of the success of the regeneration and an estimate of the length of the regeneration period (up to a dominant height of 5 m). 2. Other information corresponding to the decision tree - the costs associated with different activities; - scrub control models; - ground vegetation control models. 3. Tending program for young pine stands up to the first thinning stage. 4. The margin cost of the regeneration tome (the cost of one year's delay). The decision-maker defines, on the basis of his economic requirement level, how large the financial loss will be if one year is lost in regeneration compared to an optimum chain meeting the regeneration target in the shortest possible time. The decision-maker defines the following information in each regeneration situation: 1. Basic information about the regeneration area and regeneration - site, previous stand, tree species to be regenerated; - site qualifications; - regeneration instructions, procedures to be selected. 2. Changes in input values for the program - costs revision; - restricting or changing the measures; - estimation of the regeneration time; .....
