Forest products price time series analysis in Catalonia: Practical considerations and available outputs

Abstract

In this issue we present a second article on price time series analysis focuses on practical aspects that complement the methodology previously explained (Raddi, 2023). The development of a historical series raises a crucial operational question: should we consider the complete series, that is, starting from the first available data, or limit ourselves to a recent period? Although longer series tend to be more significant, including prices from sixty or more years ago increases the risk of introducing elements of bias. The trend lines calculated using the real price change rate reflect the interaction between supply and demand that has occurred in the past and which may change over the years. Therefore, prices from too far back should be excluded in order not to affect the outputs results. The suggested criterion for defining the period to be considered uses the economic definition of the short, medium and long term, complemented with that of forest rotation. The Observatori Forestal de Catalunya (Forest Observatory of Catalonia) provides the real price change rate of forest products calculated in the long and medium term, as well as the short-term outlook. This information allows us to determine trends, helping in the design phase of projects as well as during their management.