The urban forest

Trees make a city more beautiful, and Baltimore is blessed with an abundance of them — some 2.7 million at last count. That leafy green canopy, which acts as the city's lungs and air conditioner by cooling and cleaning our air and water, doesn't always get the attention it deserves as a critical element of the urban infrastructure. Yet if Baltimore is to remain an attractive place to live and work, its urban forest must be constantly maintained and continually renewed.

Baltimore's tree canopy — a measure of the proportion of the city shaded by trees — has been declining in recent decades, largely due to commercial and residential development and the paving over of previously green spaces. The last time the U.S. Department of Agriculture's Forest Service measured the city's tree canopy, it found its coverage had declined from about 30.5 percent of the city in 2001 to just 28.5 percent in 2005.

That may sound like a relatively small drop in percentage terms. But in absolute numbers, it means Baltimore lost the equivalent of something on the order of 100,000 trees over the span of just a few years. The Forest Service is set to release new statistics on Baltimore's canopy next year, covering the period 2005 to 2010, and if past trends are any indication, the city may have suffered a similar loss over that period.

These declines could hardly come at a worse time. The Department of Recreation and Parks, which had been planting about 1,800 trees a year on public streets and properties, had to discontinue that effort earlier this year because of cuts mandated by the city's $120 million budget deficit.

Tree Baltimore, an initiative sponsored by the mayor's office to establish public-private partnerships aimed at increasing the city's tree canopy, has planted about 6,000 a year since it was established in 2008. But it only works with private property owners and can't augment the number of street trees in the distressed inner-city neighborhoods where their absence is most noticeable.

Though the importance of trees to the urban infrastructure is often underestimated by politicians and policymakers, the tree canopy confers important environmental and health benefits on city residents.

Trees improve air quality by absorbing ozone and carbon dioxide emitted by vehicles and recycling them as oxygen. They cleanse water supplies by reducing storm water runoff from paved areas that contaminates local streams and waterways. They cool homes and businesses in summer, lowering annual utility bills.

Perhaps just as important, trees exert a significant calming effect on people's moods, helping them to cope better with the stresses of urban existence and improving their overall quality of life. And many studies have shown that the presence of trees increases the value of urban properties and makes them more attractive to prospective buyers.

That's why preserving and expanding Baltimore's tree canopy should be a long-term priority for city officials. American Forest, a national conservation association that works to protect, restore and enhance the country's wooded areas, recommends a tree canopy of at least 40 percent as the optimum for Eastern cities like Baltimore.

But achieving that goal will require a major long-term commitment to maintain the city's existing tree canopy while planting enough new trees each year to gradually increase their coverage in areas that presently have little or none. Some estimates put the cost of such an effort at up to $10 million a year over the next 20 years — a seemingly prohibitive sum, especially at a time when cities across the country are struggling with crippling budget shortfalls.

Yet preserving and expanding Baltimore's tree canopy could be one of the best long-term investments the city can make in its future. Many older residents may remember a time when North Avenue, once the city's northern boundary, was a leafy thoroughfare lined with stately rows of towering trees from one end to the other. The goal of a cleaner, greener Baltimore will never become reality unless we start somewhere, and the effort will be worthwhile it if it results in making the city a healthier, more attractive place to live and work for both current residents and future generations.

Copyright © 2019, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad