Street Trees

A tree shaded street in Suzhou, China

In this new era of global warming it is important to recognize one of the most effective and least expensive weapons for counteracting the effects of greenhouse gases on the atmospheric temperature. This weapon is the tree.

Shade trees reduce solar heat gain by transferring the active heat-absorbing surface from an inert building envelope to living foliage. Urban neighborhoods with extensive vegetation can produce air temperature reductions as great as 10 degrees F compared to nearby areas with little vegetation. The Chicago Urban Forest Climate Project (CUFCP) was established to increase the understanding of how vegetation within urban areas influences local climate, energy use and air quality.

The tree removes the major culprit in the warming trend - carbon dioxide - from the atmosphere. It then strips the oxygen breathed by humans from the CO₂ and puts it back into the atmosphere. It does all of this at no cost to the global economy.

Trees are nature's air conditioners. In these times of high energy costs, deciduous trees cool buildings in the summer and let the sun shine through in the winter. They do this in exchange for minimal maintenance.

City trees are fourteen times more valuable than their rural counterparts due to benefits that address urban conditions. A study of arid Tucson, AZ, showed that for every $1 spent to maintain trees, $2.62 worth of benefits was returned in the form of air-conditioning energy savings, dust reduction, and the slowing of storm water runoff.

City trees are the only capital improvements that increase in value over time. Healthy trees can increase property values up to 20%. Careful species selection and proper planting techniques will prevent sidewalk damage and lawsuits and avoid unnecessary maintenance costs.

Our City Forest (OCF), is a non-profit created in San Jose to help remedy the deficit in city trees. Other cities may have equivalent public or nonprofit entities ready to assist residents in the planting of new street trees.


The two images above were taken at the same place and show the same street. The difference is that the first looks to the west and the second to the east. Amazing what a difference a few trees makes. Question to self - Why do I seem to have this affinity for garbage day on these street tree photos?

These paired images of San Jose illustrate better than words the benefit of trees for the urban environment. The site contains two sets of photos: one taken in 1975, and saved from the trash by a conscientious city employee, and the other taken in 2006. Beside the obvious changes in San Jose's built environment, the most significant positive change was generated by the trees planted along these streets in the city's downtown.