Forest companies are currently investing strong amount of money in establishment of plantations, that implies the carrying out of various kinds of silviculture-based works or procedures, these bring about additional costs to the plantation, and if being suitable for the site, they shall generate income increase by the time the forest is harvested. In this context, decisions to be made by the time a plantation is establish turn out to be critical with respect to the business income-yield capacity. Therefore, and due to economic restraints, available resources have to be properly allotted in order to achieve improvement regarding forest business income-yield capacity, in the case of a group of forest stands that feature their own productivity, localization and gathering. The purpose of this current research work has been to improve the forest business income-yield capacity, by developing a support system regarding silviculture-based decision making in the establishment of forest plantations (PROYMAN). By means of the use of this model a solution showing no establishment taking part, against a current silviculture decision, and one achieved by the decision making support system. Outcomes showed that better general results were obtained by PROYMAN, in terms of Land Expected Value (LEV). Besides, it is important to stand out that key variables parameterization with respect to the establishment process turns out to be a necessary characteristic. Likewise, it is quite important for a decision making support system, since the proper management of such decisions shall bring about the suitable and right solutions.