Forest Service study shows major U.S. cities losing tree cover, but active tree planting can stem the tide

Earlier this month, Texas was reported to have lost 5.6 million urban trees due to last summer’s drought. Now, the U.S. Forest Service reports that the tree canopy in many other cities are similarly under stress.

In 17 of the 20 cities analyzed, tree cover declined, while impervious cover such as pavement and concrete increased in 16 of the 20. The cities experiencing the highest percentage of lost tree cover were Houston, Albuquerque and New Orleans. One city, Syracuse, New York, experienced a slight increase in existing tree cover, but that was due largely to the spread of the invasive European buckthorn.

Overall, existing tree cover in U.S. cities is declining by about 0.9 percent annually, and it comes at a cost. According to Forest Service estimates, urban trees provide a benefit worth three times the cost of tree care. Communities do not want to lose these benefits, which include reduced heating and cooling costs and improved storm water management, on top of the less quantifiable boost to quality of life.

There is some good news, however. The Forest Service study also showed that active tree planting and maintenance efforts are already making a difference. Said Forest researcher  David Nowak: “Tree cover loss would be higher if not for the tree planting efforts cities have undertaken in the past several years.”

To reverse the trend, continued tree planting and more active and comprehensive efforts to sustain urban tree canopies will be required.

Saving urban trees will take a lot of work, but thousands of communities – particularly the 3,462 currently designed as a Tree City USA – have already shown they are up to the task.

Photo credit: TreesAtlanta, via the U.S. Forest Service.

Summer drought costs Texas 5.6 million urban trees

A new report from the Texas Forest Service found that cities in the Lone Star State lost 5.6 million trees due to drought last year. The trees, comprising 10 percent of Texas’ urban forest, had become “too thirsty to live,” as the Austin American-Statesman put it.

The drought’s impact on trees has put Texas officials in a tough spot. The same report detailing the lost trees also pointed to $280 million in annual environmental and economic benefit from trees, and that’s in addition to the qualitative benefits. It’s hard to put a numeric value on the thousands of missing pine trees from Houston Memorial Park, for instance, but their loss is undoubtedly felt.

In urban areas especially, trees play a critical role in shading buildings and streets, reducing the risk of flooding and keeping pollution down.

Removing trees is expensive, though well worth the cost to avoid risking a fall on a car, a power line or a home. Getting rid of dead or dying trees will cost the state of Texas $560 million dollars, the report says.

Texas’ large metropolitan areas, such as Houston, Dallas and Austin (above), currently have a total of 60 million trees.

Last summer is on record as one of the longest and driest in Texas history, and the trend looks likely to continue. Broader changes in climate cannot be solved at the local level alone, but there is a lot that cities can do to mitigate the damage.

In Austin, for instance, the Texas live oak has been more drought-resistant because its natural reserves are a good fit for the area. City Arborist Michael Embesi told the American-Statesman that Austin had already shifted to planting less water-dependent trees in preparation for last summer. Planting the right species at the right time definitely helps.

Cities are strapped for resources, making watering trees a challenge, but the right infrastructure could tap dirty water – from car washes, local reservoirs or excess rain that would otherwise end up down the storm drain – during the summer. Additional watering will assist trees on the margins of survival in making it through the dry season.

It’s also beneficial to plan for replacing older trees.

Solutions like these emerge from a sustained commitment to managing urban trees. Texas already has 72 Tree City USAs, including most of its largest cities, so it is clear that both motivation and resources exist to respond to these challenges, along with the passion of concerned professionals and the communities they serve.

You can find out more about the Texas Forest Service’s study here.

Photo courtesy of Fine Austin Living.