Simulation is a highly valuable tool for environmental, ecological and forestry research, and in decision making for environmental resources management. Simulation models allow representing the complexity of various processes and integrating the information from many investigations in a system that can be used to predict its future state and to evaluate the effect of decision alternatives. The aim of this work was to illustrate the potential of the declarative-visual programming languages for representing, implementing and simulating in a simple way a relatively complex forest system. A growth and yield simulator prototype was created for teak plantations (Tectona grandis). The model consists of a differential equations system following the space-state approach. The simulator was implemented in SIMILE v.6.0, a declarative-visual language, and was used to analyze plantation growth, harvestable volume and carbon sequestration capacity in response to silvicultural management scenarios: site quality, initial spacing and thinning schedule. This work is an example of the potential of these languages, particularly for educational purposes because it facilitates the experimentation of alternatives and sensitivity analyses by simultaneously testing many scenarios to assess the effect of changes in model parameters, to examine model assumptions, data quality, construction approach, computing algorithm efficiency and predictions quality.