Benefits of Trees

In addition to beautifying the region, trees and other vegetation absorb pollution, curb the heat island effect, control stormwater runoff, and save energy costs.

A 2000 study by American Forests calculated the economic value of some of these services. Existing trees in the region remove an estimated 83 million pounds of air pollutants each year. This annual air pollution removal is valued at $208 million, reflecting the price that society would have paid, such as health care costs, if the trees did not exist. Area trees also control 2.4 billion cubic feet of stormwater when it rains. This calculates into a one-time $1.33 billion savings on construction of stormwater management systems. Shade from trees reduces air conditioning costs. An average single-family, detached home saves $72 annually because of trees, according to the research. This adds up to city-wide savings of $26 million each year.

Tree Loss

The study found a 16 percent decline of the urban canopy in the area over the last three decades. In 1972, more than one million acres in the region had 50 percent or greater tree cover. That figure dropped by 150,000 acres in 1999. Conversely, area with less than 20 percent tree cover increased by 13 percent, or 200,000 acres, in the same time period.

Tree Protection

Cities in the Gulf Coast Region have varying policies that protect certain trees. The City of Houston Tree and Shrub Ordinance requires people to acquire city permission before removing trees larger than 1.5 inches in diameter that are located in public rights of ways, including esplanades and the area between sidewalks and the street. It also protects very large trees in commercial developments.

Enforcement of the tree ordinance has been a problem in the past. However, the City of Houston recently created a position dedicated to tree protection, and the situation may improve.

The current tree ordinance does little to protect trees on private property. Because trees offer so many benefits to our region, some suggest implementing a more comprehensive plan that protects all trees and requires mitigation efforts to replace any that are destroyed.

Some also suggest that trees be considered in all public works, transportation, and development decisions. Tree planting and protection are inexpensive, non-invasive methods for air pollution reduction and stormwater management. Several groups are working to add these strategies to the State Implementation Plan to reduce ground-level ozone (see Air Pollution).

Recent Progress

Blue Ribbon Tree Committee

In March of 2001, Houston Mayor Lee P. Brown convened a special committee to review the city’s tree planting and protection ordinances and address larger tree issues. In September, co-chairs of the Blue Ribbon Tree Committee, representing developers, beautification groups, and environmental organizations, submitted their 25-page report. Many participants were satisfied with its suggested changes to the city’s tree regulations, including tree requirements for single-family residential developments, stricter placement of trees along street frontages and in parking lots, and a variety of education and enforcement measures. However, some were disappointed and frustrated that the larger environmental concerns related to trees, such as the relationship among tree canopy, the urban heat island effect, and air quality, were not addressed.

Houston Green Continued

The Texas Forest Service (TFS) has received federal funds to further analyze the region’s existing tree resources and their role in reducing air pollutants and the urban heat island effect. The project will build on the work of Houston Green, a coalition of regional government, business, and nonprofit organizations that released a report in December 2000 that estimates the economic value of the tree canopy in the Houston-Gulf Coast region. The final product of this further research will be computer software that local tree organizations can use to determine the effects of existing tree cover, select priority planting sites, and help with planning and management activities.

What You Can Do

Plant trees

Trees for Houston, a local non-profit organization, sells trees to plant in parks, esplanades, and along street rights-of-way. Call (713) 840-8733 to learn more. Annually, to celebrate Arbor Day, the Parks and Recreation Department provides free tree seedlings to the public. Call (713) 845-1000 for more information.

Report tree ordinance violators

Citizens may report potential violations of the Tree and Shrub Ordinance by calling TreeScape at (713) 942-7275. Watch for trees in danger as well. Trees with ribbons tied around them may be about to get the axe.

Register an old tree

The Harris County Tree Registry, established in 1992, recognizes the largest trees of each native genus and species in Harris County. If you would like to nominate a tree, contact the Park People at (713) 942-PARK. A volunteer forester will measure it; qualifying trees will receive a certificate and be listed in the next edition of the registry.