The Effects of "Green Curtain" on Micro-Environments.

As global warming is an empirically verifiable scientific fact, human beings are facing a crucial point of no return.  The rationale for this study was to conduct an examination of the prospects for the potential utilization of a “Green Curtain (biological shutter)” in the UAE in order to facilitate awareness of, and participation in, sustainable development.  Experimental green curtain plots with four tropical perennial species with distinctive climbing vines, Clitoria ternatea L., Jasminum azoricum, Mandevilla splendens, and Tristellateia australasiae, were established in a university courtyard garden in Dubai.  The effects of natural green curtains were determined by measuring the surrounding micro-environments (temperature and humidity), and examining concomitant biological characteristics (heat and pest resistance; speed of growth and canopy development; and density, color, and uniformity of the canopy).  Approximately 13 weeks from the planting of seedlings (eight seedlings/plot), Clitoria ternatea L. developed into dense and uniform natural green curtains, and covered the entire area of 2.5m x 3.5m wire-meshed stockades (canopy density was 86%), while Tristellateia australasiae green curtains were established in 15 weeks (canopy density was 62%).  Jasminum azoricum did not develop a uniform canopy, and Mandevilla splendens grew vertically without spreading horizontally.  The mean micro-environment air temperatures and humidity during mid-day (8:30-16:30) in the established green curtain plot was 36.67°C and 34.68%, respectively, while that of a control plot was 39.16°C and 29.99%.  Differences between the tendency of temperature and humidity changes in the green curtain and control plots (a short lag period and gradual temperature rises, and gradual humidity drops) indicated that the green curtains reduce the micro-environment air temperature not only by physically blocking radiation, but also through the biological function of transpiration.  Among the four tropical vine species examined, Clitoria ternatea L. green curtains developed most glamorously and uniformly, and the fastest.  The green curtain effectively reduced the surrounding micro-environment temperatures, and retained humidity during mid-day, which suggests a possible reduction of energy consumption.