Wood in the human environment : restorative properties of wood in the built indoor environment

In this study, the stress-reducing effects of wood and plants were studied in the context of an office environment. This study took a psychophysiological approach to stress and attempted to assess the sympathetic and parasympathetic branches of the autonomic nervous system. Four office environments were studied in this factorial design: wood and plants, wood and no plants, no wood and plants, and no wood and no plants. One hundred and nineteen university undergraduate students were assigned to one of four test conditions. Skin conductance and inter beat interval were continuously monitored throughout the experiment. The experiment consisted of a 10-minute baseline period, a 12-20 minute stressful task, and a 10-minute recovery period. Wood effects were found with respect to skin conductance level (SCL) and frequency of non-specific skin conductance responses (F-NS-SCR), both indicators of sympathetic system activation. Subjects exposed to wood had lower SCL in the baseline period and lowers F-NS-SCR in all periods of the study. No plant effect was found with respect to sympathetic activation. Further, there was no evidence of wood-plant interactions. Spectral analysis of HRV data was used to measure parasympathetic activation. No treatment effects were found with respect to parasympathetic activation. This study provides evidence that wood provides stress-reducing effects similar to the well studied effect of exposure to nature in the field of environmental psychology. The practical implication of this effect is that wood may be able to be applied indoors to provide stress reduction as a part of the evidence-based and biophilic designs of hospitals, offices, schools, and other built environments.Forestry, Faculty ofGraduat