Last Monday I attended meetings on urban trees and tree care with members of the Utah Community Forest Council and International Society of Arboriculture, Utah Chapter. It sounds very official because it is.

These people are self-avowed tree huggers. Their "arbor ardor" has a practical bent. They focus on making sure the trees they choose to hug are healthy and safe enough to gather the family and enjoy a summer picnic under. They take classes, study, take tests and get certified in tree care. They work with trees, climb them, prune them, treat tree diseases, insect invasions and injuries, and evaluate trees to determine whether or not they are really worth saving. They also remove trees that don't pass the assessment.

The difference between a true tree hugger and the rest of us is how they see trees. Most of us look down a tree-lined street or into neighborhoods or parks with healthy trees and generally get a good feeling about the ambiance there. We may or may not make the association that it is the trees that create that feeling, other than noting shady areas.

True tree huggers on the other hand see the trees and recognize that they are exactly what make an area so beautiful. They share the same generalized feel-good sensation as the rest of us, but their response is much more than that. They see the trees first. They can identify the trees by variety, analyze the layout of the landscape relative to the trees and can even put a solid dollar value on them.

How do you appraise the value of a tree in an urban area? Is it worth what it cost initially? Growing, getting larger, and adding shade must be worth something, but how do you calculate it? Is it all about creating beauty and ambiance? How do you evaluate that in a practical manner? Realtors will tell you that a landscaped home with healthy well-established trees will sell for a higher amount than a similar piece of property without the trees. It is said that a healthy, well-placed mature tree in the landscape adds 1 percent to the selling value of a home.

A speaker at Monday's conference is a bonafide true tree hugger. He has made a career of evaluating the value of trees in the urban landscape. Dr. Greg McPherson is the director for the Center for Urban Forest Research, USDA Forest Service in Davis, Calif. He conducts research that measures and models the benefits and costs of urban forests in cities across the country. The results differ from city to city, because he bases his research on measurable data. In his spare time he teaches courses at UC Davis.

He pointed out that cities without trees are dirty, the water is not as clean, the air is more likely to be polluted and summer temperatures are notably higher than in cities with trees. In addition, people tend to be happier, crime rates are reduced and businesses have a higher bottom line in areas with trees. Tree-filled neighborhoods have less domestic violence, and overall, people are healthier. They create ecosystems favorable to people and animals.

Of course, there are variables. Not everyone knows how to choose and plant a tree and do it well. Often they are placed where there is not enough room, sometimes they are misused, and sometimes they are put in a place where they become a hazard with brittle branches hanging over roofs and walkways or roots lifting walkways making them uneven. Misused, they become a liability rather than an asset.

True tree huggers are perhaps a different cut of cloth. They have an interesting way of looking at life with trees.

For example, how would you do on this quiz?

You have a healthy 9-year-old Bradford pear. It is 30 feet tall. How many leaves does it have on it and what is the total leaf surface area if those leaves were somehow clipped and knit together to form a continuous membrane?

"Who cares?" you might ask.

The answer is, "researchers who are determining tree value -- and cities and communities considering the cost of the trees they plant and maintain using those figures." Those people care.

The answer to the question about the Bradford pear is the tree has 88,908 leaves comprising 3,746 square feet of surface area. The lucky interns who got to count all those leaves and figure out the surface area must have counted leaves in their sleep at night. The things people will do to get a degree...

But the numbers are important, because that leaf area provides amazing benefits. When cities are making decisions on planting and maintaining trees, they offset the benefit of the trees against the costs of planting, watering, pruning, raking leaves, cleaning up debris and otherwise maintaining them. As a tree grows and matures, the leaf numbers and area dramatically increase and the positive dollar values increase.

Trees clean up pollutants in the air and out of the soil, and they provide shade.

Here are some quantifiable results of growing trees. The cost of electricity goes down for air conditioning in buildings that have trees shading them. Shade over pavement makes it last longer and reduces the heat it gives off, which affects air temperatures in general and air conditioning expenses as a result. Leaves transpire moisture into the air which further aids in cooling the general atmosphere.

Rows of trees reduce wind speed and help reduce the chilling effects of winter winds -- another fuel savings.

Any time you use less power, the load on power plants is reduced, energy production diminishes and so do the emissions they give off to produce that energy. Tree leaves -- and needles on conifers -- actually catch and absorb particulate pollutants out of the air, but if power plants are used less, fewer pollutants are in the air to begin with. Trees also reduce the amount of atmospheric carbon dioxide and ozone. Those quantities can be measured in pounds. And an additional benefit is that when the time does come for a tree to be removed, it can be a fuel to feed power plants or mulched to enrich soil growing other trees. Trees also hold soil in place reducing erosion and they help absorb and direct rainwater and run-off in heavy storms.

According to a study that the Center for Urban Forest Research did for the city of Albuquerque, a single 20-year-old ash tree saves the city $21 per year and 11 percent in heating savings -- above and beyond the cost of maintenance. The results vary from city to city largely based on the cost of utilities and numbers of trees in the environment.

Choosing the right trees also makes a difference since some live longer in tough environments, some clean up more pollutants than others and some provide more shade. Bigger is better when it comes to these benefits.

As spring rolls around -- and it will one of these months -- consider putting trees into your yard. Choose well and plant it right so your tree can grow long and give you the full benefit of its existence.