From the time lumber is removed from the kiln to the time the remanufacturer uses it, it can be exposed to many different humidities With exposure to severe humidities, cupping in the final product can occur. This paper considers if humidity conditions during storage and transportation can significantly influence drying stresses and prong lest response. To determine the influence of exposure to different humidities, dried lumber was slowly equilibrated to 7,5% moisture content. It was than cut into blocks. The blocks were exposed to various humidity scenarios lo simulate actual storage and transportation conditions. Stress levels, moisture content and prong response were recorded. The analysis showed that stress level and prong response were strongly influenced by exposure to different humidities. The analysis also indicated that returning lumber to 7.5% equilibrium moisture content did not return the stress level or prong response to the original values. These combined results confirm that the prong test cannot be used as an indicator of how well the lumber has been dried or conditioned after it has been stored and transported. This makes seller/buyer disagreements difficult to resolve.