  This paper addresses the problem of testing for persistence in the effects of
the shocks affecting the prices of renewable commodities, which have potential
implications on stabilization policies and economic forecasting, among other
areas. A robust methodology is employed that enables the determination of the
potential presence and number of instant/gradual structural changes in the
series, stationarity testing conditional on the number of changes detected, and
the detection of change points. This procedure is applied to the annual real
prices of eighteen renewable commodities over the period of 1900-2018. Results
indicate that most of the series display non-linear features, including
quadratic patterns and regime transitions that often coincide with well-known
political and economic episodes. The conclusions of stationarity testing
suggest that roughly half of the series are integrated. Stationarity fails to
be rejected for grains, whereas most livestock and textile commodities do
reject stationarity. Evidence is mixed in all soft commodities and tropical
crops, where stationarity can be rejected in approximately half of the cases.
The implication would be that for these commodities, stabilization schemes
would not be recommended.
