Forecasting and investigation of wood price fluctuations in major species of Caspian forests

Pricing and wood price prediction has an important role in the marketing and sales of wood products, and has recently been of interest for managers. The aim of this research was to use price time series of different species to predict the expected average price and investigating of their price trends in the past in the Caspian forests. First of all, historic stumpage price data on main species were collected for the period of 24 years from 1993 to 2016. Then, to determine the real stumpage price the adjusted variable costs were deducted from the real price beside forest roads. Consumer price Index (CPI) in base year 2012 was used for deflation of stumpage price. Investigation of stationary stochastic process of time series was tested by generalized Dickey Fuller test from unit root tests using EVIWS 10 software. Then validity of regression models was investigated by multiple regression analysis using SPSS23 software. Finally, the mean expected price of different species was estimated by the parameters of the autoregressive models. The results showed that real prices in past periods had random fluctuations, and the nonstationary hypothesis of time series was rejected based on β = 1, since there was 0