If you think the recent 101-degree temperature was hot, imagine what 112 degrees would have felt like. That’s how hot it might have been without nature’s air conditioners – trees – working 24 hours a day. Arguably the city’s most valuable natural resource, the urban forest has the collective cooling capacity to lower temperatures in the city by as much as 11 degrees. Amazingly one single mature tree provides the cooling equivalent of five average room air conditioners running 12 hours per day.

If that’s not enough to convince you to hug your favorite tree, consider the money you can save. PG&E reports that shade trees save from 10 to 50 percent on cooling costs. And because trees reduce air conditioning demands, fossil fuel emissions are also reduced. This means cleaner air and less smog. And when you add even a few other benefits such as increased property values, significant glare and noise reduction, and the intake of carbon dioxide and other dangerous gases, you have to wonder how it is that we’ve come to take for granted this highly sophisticated, clean and wondrous technology.

Yet we have. The American Forestry Association reports that in large cities throughout the country, only one tree is planted for every four that are removed. Urban forests are getting smaller while cities are getting hotter and dirtier. As cities grow and demands for services increase, municipal tree budgets are not able to keep up with the need. What to do? The private sector must step in to fill the gap.

In Sacremento, the utility industry did just that with the question: If nature can do the job, do we really need another power plant? The Sacremento Municipal Utility District said no. In 1992, it opted instead to fund the planting of half a million trees rather than a new power plant, thus beautifying the city, restoring the urban ecosystem, fostering community involvement and reaping mega-public relations benefits, all while meeting the objective to lower peak summer temperatures. Makes sense to me.

And in cities everywhere, volunteers are stepping up. The “One Million People, One Million Trees” campaign begun in 1992 by San Jose’s Our City Forest brought together 135 community leaders from more than 100 local organizations. Volunteer tree planting was identified as a powerful vehicle for fostering community ties by bringing people together on common ground.

How can such a simple act of planting a tree carry such power? What is it about hands-on involvement that can strengthen a person’s connection and commitment to a community? When urban ills such as graffiti, litter and vandalism occur, citizens do not feel a sense of ownership over their environment. But when trees are planted as a community project, the trees become very visible, and residents take pride in their well-being. They notice if the trees need water or show signs of stress or disease. As a result, the survival rate for trees planted by volunteers is 85 percent vs. only 50 percent when citizens are not involved in the process.

With the help of trained, enthusiastic volunteers, Our City Forest is working with schools, neighborhood groups, service organizations and businesses to create a more sustainable and more involved city. The program’s success is measured by how many people participate as well as by how many trees are planted. Nearly 10,000 citizens have attended educational workshops and helped plant and care for 2,000 trees in the last year. With the city unable to fund a tree replacement program at this time due to budget constraints, these volunteers are filling a huge gap.

The value of San Jose’s urban forest is conservatively estimated at $3 billion. Considering its economic, environmental and social value, the cost of stewarding this great asset is well worth our investment. And as “shareholders” of this vast resource, we each receive a personal treasure chest filled with clean air, serenity, beauty, joy and magic. It may be the cheapest thrill you’ll ever get.