The application of trend estimation model in predicting the average selling price of timber

The article analyzes the possibility of adopting trend estimation model to predict the average selling price of timber (CGUS). The study used information about the average selling prices of timber in chosen periods (2006-2017). The data concerning the actual CGUS was used to create a trend estimation model. The models and CGUS predictions were conducted based on three different time series encompassing 5-year periods. The predicted (CGUS) trend estimation in particular years was requested based on extrapolation, which exceeded the accepted set of information used in the study to create a trend estimation model. On the basis of the conducted study it was ascertained that the method of modeling linear trend estimation should be adopted in the price prediction process. The error assessment with which the linear function formulas are burdened, it was noticed that the value of the coefficient of residual variation was between 4.40% and 7.82%. It was also noticed that the linear modeling of CGUS trend estimation, despite unfavorable values of coefficient of determination and convergence, to some extent, can be viewed as an assistance tool in the decisionmaking process in the scope of predicting the height of the analyzed price. This view was supported by the achieved predictions which were verified with the actual prices of timber. The price difference between the actual and the predicted one was between -1.59 PLN to 2.27 PLN, and in relative terms the predictive error was between 0.83 to 1.15%. In our opinion the presented research process can constitute a reference point as a comparative element to verify the results for other, new price prediction models. The process of modeling timber prices should be extended by other predicators which are connected with forest market chain.