Excerpt from Monthly Stumpage Prices for the Pacific NorthwestThe simplest smoothing technique used in forestry is a moving average of several periods. Another approach that could be used for stumpage price series is seasonal adjustment, which is really a special form of smoothing, it removes seasonal (cyclical) oscillations from the series rather than irregular short-term fluctuations.Seasonal adjustment techniques'2 are based on the premise that a time series can be represented as the product of four components: the long-term secular trend in the series, a seasonal component, a long-term cyclical component, and an irregular com ponent. The methods for eliminating the seasonal component are ad hoc and do not guarantee removal of all the seasonality from the original series. The process pro vides information about the existence of seasonal patterns in the price data and indicates any long-term trend in the data.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.