It Raises Property Value of Homes and Neighborhoods
Urban trees often have substantial monetary values. A number of studies have shown that real estate agents and home buyers assign between 10 and 23 percent of the value of a residence to the trees on the property. Local governments capture some of this monetary value because enhanced property values increase assessed values and the tax base.
Not caring for trees properly in neighborhoods and the urban forest often results in “Tree Topping”
There are numerous examples across the country of streets or entire neighborhoods where a large number of trees have been seemingly cut in half or otherwise permanently damaged (one common practice is “topping”). These damaging practices are usually performed by low-budget contractors often referring to themselves “tree experts” and are further propagated via a social learning (aka: neighbor see, neighbor do) combined with misinformation. The practitioners often possess little to no scientific or safety training, use older and poorly maintained (more dangerous) equipment. The costs associated with their activities in a single neighborhood can easily reach seven figures. When trees are mistreated, not only can they be permanently damaged, property values and the health of the urban forest can be damaged as well. In short, healthy, well-maintained and located trees can yield considerable value and many benefits, not only for a single property, but for surrounding properties as well. As time passes and trees grow, their benefits and values increase exponentially.
Topped trees have greatly reduced lifespans, increased risks of failure as new sprouts grow, and much higher maintenance requirements.
Psychological Value of Trees in Neighborhoods:
Uplifted spirits is one important benefit of trees. Some of the difficulty in measuring these benefits may grow out of society's decision to exclude tree values from the marketplace. Other emotion-based commodities, such as flowers, perfume, view property, prestige automobiles, and entertainment, are readily assigned monetary values. But with proper treatment, researchers can tie monetary values to the emotional benefits of trees.
The pleasure and good feelings we associate with trees may be far more practical than generally believed. Data on the connection between vegetation and human health are beginning to accumulate. For example, surgery patients who could see a grove of deciduous trees recuperated faster and required less pain-killing medicine than matched patients who viewed only brick walls. And, prisoners with cells overlooking green landscapes used prison health facilities significantly less than prisoners whose cells provided views of other prison facilities.
Historic Values of Trees
Trees provide important symbolic links with the past. If a living tree is associated with important events, the tree takes on historical valuesunrelated to aesthetics or usefulness. For example, a community would normally value a tree that shaded the deliberations of the community's founders. A tree would also be valuable if planted by George Washington or some other important figure in history. Aside from specific events, old trees may be regarded as important simply because they have lived through eras with which we have few other connections.
Environmental Values of Trees in Neighborhoods
People value both the aesthetic and physical quality of our environment. Trees contribute to this quality by modifying local climates, reducing noise and air pollution, and by protecting soil and water. Climate control is one important service trees provide naturally in the landscape, but the urban landscape is far from natural. Streets, parking lots and buildings have changed the climate of urban areas by absorbing solar radiation. Water that once percolated into the soil and later evaporated from soil and plants now drains away or dries on the hard surfaces. These changes have increased the temperatures of cities. Compared to the surrounding rural areas, the urban "heat islands" are five to nine degrees Fahrenheit warmer.
Trees help moderate the "heat island" effect. They also greatly increase human comfort: indoors or outdoors. On hot days, trees pump hundreds of gallons of water through their foliage. This water evaporates, keeping the tree and its immediate surroundings cool.
While groves of trees reduce local air temperatures, individual trees increase human comfort primarily by controlling solar radiation, not air temperature. Trees and other vegetation shield people from direct sunlight. Trees also shade soil, pavement, buildings, and other surfaces that would absorb solar energy and then radiate that heat back to the surroundings. Without the protection of trees, city dwellers are literally surrounded by radiant heat.
Indoor air temperatures are also affected by trees growing around buildings. During hot weather, trees reduce cooling costs by buffering high air temperatures and blocking unwanted solar energy.
Noise pollution from highways and other sources can be reduced with trees. Used alone, trees must be planted in belts 35 to 100 feet wide to create noticeable reductions. However, earth berms can cut traffic noise by up to half, if they are tall enough to hide the source of noise and are planted with trees, shrubs, and grasses. Where this kind of adjustment to the topography is not possible, a row of trees and a solid wall reaching up to the base of the crowns will provide a similar reduction.
Soil and water quality are protected by trees. In urban settings, large areas are covered by buildings, pavement, and other impervious surfaces. Instead of percolating into the soil, rainwater and snowmelt are concentrated and accelerated, increasing soil erosion and silt accumulation in streams.
Trees and other vegetation protect the soil from erosion. Along watercourses, roots and fallen leaves help hold the soil together and shield it against the cutting forces of surface water. Vegetation also absorbs some of the force of failing rain, so soil particles are not dislodged. And, the leaf litter that accumulates under trees creates an environment for earthworms and other organisms that help maintain soil porosity.