t of 30 species, Mangifera indica (the mango tree) was the most tolerant plant and performed well as the first curtain plant of a greenbelt, with other excellent performers including Ficus benghalensis, Ficus infectoria and Mimusops elengi.
Another aspect of green buffer design is that trees can suffer from chronic toxicity symptoms due to the continuing impact of low level pollution , so the maintenance and monitoring of the greenbelt areas is needed. It is important to have service lanes for access to all areas and to perform frequent observations of growth rate, plant pathogens and syndromes. These observations should be recorded, and replacement and re-planting of the greenbelts may be needed.
Other benefits of the better eco-industrial town: Identified from mapping studies, there are factories situated outside the industrial zone along the main streets; therefore, a “green corridor” can be applied to these main streets. Together with a city’s “green lung,” it is the place where parks and urban forests exist (Figure 5). It is com monly recognized by the public now, and the green area in a city should be a basic requirement in all planning. McPherson, Scott, and Simpson  explained that trees absorb gaseous pollutants through leaf stomata and can bind or dissolve water soluble pollutants on moist leaf surfaces. Tree canopies also intercept particulates and reduce local air temperatures, and micro climates are the most effective energy efficiency programs . Therefore, planning a “green system” in industrial areas is not just an accessorial option, and it should be combined with the transportation system, utilities and piping systems, water system and other management and logistical systems. Sustainable development of the eco-industrial town should consider the land utilization “tripod”  and focus more on the reinvention of public green space to encourage land use for other purposes than only traditional economic benefit.
Figure 5. The 2008 Olympic Forest Park was originally planned to be “a green lung” of Beijing (Sources: Beijing Tsinghua Urban Planning & Design Institute).
Figure 6. Overlay map of the proposed 1) Bio-indicator, 2) Greenwall, 3) Cushion, and 4) Green corridor as “a green area system” on the Land-Use Master Plan for the seashore area (Excerpted by A. Aruninta. Sources: Department of Public Works and Town & Country Planning).
Sustainable development should also emphasize socioeconomic factors. The election of plant species in a greenbelt is not only determined and evaluated by biological and biochemical characteristics, such as APTI, plant habit, canopy structure, type of plant and laminar structure , but also socioeconomic values such as maintenance cost and community preferences. Plants with longer lifespan are also preferred for economic returns.
Combining all factors and purposes, landscape architectural science and the art of designing green buffers for eco-industrial towns such as the Rayong Industrial Estates are crucial and effective measures. Landscape design, especially planting design, offers wide benefits including aesthetic, socioeconomic and ecological (such as bio-indicator, biochemical filtering of the air and reduction of temperature). Designing a green buffer—i.e., “green corridor”, “green lung”, “green wall”, “cushion” and “bio-indicator”—requires an understanding of environmental engineering science, horticulture, micro climates and meteorological conditions and the release pattern and chemical dispersion behavior of the pollutants. Finally, the study suggests having a “green area system” (Figure 6), which is a significant consideration of green planning together with other systems. Providing an efficient green area system would involve pollutant attenuators, absorbers, trappers, indicators, cushions and buffers that do the utmost to promote sustainable planning and prevent industrial disaster for the eco-industrial town.
This paper was presented and published in the proceeding of the ICHES2011: The 4th International Conference on Human-Environment System, 3-6 October, 2011. Hosted by Japanese Society of Human-Environment System, Hokkaido University.