The influence of moisture changes on the deformation of stressed wood was studied in small-scale initially green beams of collapsible and non-collapsible species of wood to determine if mechano-sorptive effects accompany volume changes due to cell wall collapse, with loss of free water from cell lumens, as well as volume changes due to normal shrinkage, with loss of chemically bound water from the cell wall. Greatly enhanced deflections were measured in the beams in the presence of both types of shrinkage. The relative deflections determined during abnormal shrinkage, whenever it occurred, were almost four times those determined during normal shrinkage, as drying continued from the green state to 10 per cent moisture content. The experiments provided further evidence on previous proposals advanced by the author that mechano-sorptive behaviour in wood is conditional on volume changes accompanying water movement in wood substance. The effects of moisture changes on the deflections of initially green and partially dried beams of structural size were also studied and practical recommendations advanced to lessen the detrimental effects of mechano-sorptive deformations in initially green timber structures.