Healthy trees provide significant air quality benefits. Their creation of oxygen as part of the photosynthetic process is well known, but they also remove air pollutants via leaf stomata and leaf/plant surfaces. Gases are absorbed, while particles are held until the next rainfall or dropped to the ground with leaf and twig fall. By blocking sunlight and creating shade, trees also reduce air temperatures, which reduces sunlight-dependent chemical reactions such as ozone formation. This effect is particularly significant in urban areas, where trees can alleviate the “heat island effect” created by the concentration of buildings and roads. Finally, trees that shade buildings reduce energy use in the summer by reducing the need for cooling. RC&D Councils have run many tree planting projects over the years to increase air quality, beautify communities, and improve wildlife habitat. Here is a sample of such projects:
Saginaw Bay RC&D Council in Michigan has implemented a Tree Planting for Carbon Credit program. The purpose of the project was to sequester carbon by establishing stands of tress that would accumulate carbon for at least 40 years and provide soil conservation, forest products, and wildlife habitat. This project, funded by the power company Detroit Edison, planted 861 acres of trees on private farmland. This equates to 585,480 trees being planted throughout the power company’s service area. The air quality benefits have been very significant: one tree sequesters enough carbon over 40 years to equate to more than $30,000 in cleaner air.