Mounting Evidence of the Value of Urban Trees

Researchers in the Pacific Northwest have quantified the importance of urban street trees on rental values using Craigslist apartment listings in Portland, Oregon and tree data from Google Earth.

“Each tree on a house’s lot increases monthly rent by $5.62 and a tree in the public right of way increased rent by $21.00.”

One of the researchers, economist Geoffrey Donovan of the U.S. Forest Service had already linked the presence of urban trees to lower crime rates (particularly large, mature trees,) healthier newborns, energy conservation and pollution control as well as an an average $8,900 increase in the sales price for property. Sometimes the benefits accrue even if the trees are next door.

The linkages hold true even when the researchers control for other factors that determine a neighborhood’s desirability. Other researchers with the Federal Highway Administration have also been able to quantify the value of roadside trees along the National Highway System.

Portland, Oregon, where the study was conducted, has a 26% urban tree canopy remaining but hopes to increase it to 33% by planting 415,000 trees.

While some areas of the country strive to increase their urban tree canopy, other areas are seeing significant decreases in theirs. For example, Mecklenburg County, North Carolina including Charlotte, the state’s largest city conducted a study through American Forests to quantify the value of its remaining 51% of urban tree canopy, a full third of which has been lost since 1993.

The tree canopy in Wake County, North Carolina’s second largest and home to the state capital Raleigh has been reduced to 44% tree cover even though its land area is two to three times the size of counties at other points of the broad Research Triangle Area.

Still fifty-one-percent forested and above average for urban areas in North Carolina, nearby Durham County was fortunate to limit loss to its tree canopy to 2% while growing another 20% in population over the past decade.

Making this even more remarkable is the fact that Durham County is the 17th smallest land area in the state, while the 6th most populous. Additionally, Durham County is even more compact because more than a third of the land area has been set aside in low-density watershed even though the County is host to the City of Durham, the fifth most populous urban area.

Indeed, Durham is well deserving of the moniker: “The City of Trees,” a place where activists conduct “Tree Camps” and Duke Professor Will Wilson has published a new primer on urban environments and an Durham Tree Alliance is under development.

Ironically, as North Carolina’s urban cities and counties are catching on to the value of tree canopy, the State General Assembly, under new ownership is apparently eager to reclaim the state’s once-fading reputation as backward by authorizing massive clear cutting along roadsides, not to make what remains of the state’s vaunted scenery more apparent but as a public gratuity to the 8,000 outdoor billboards.

Hopefully, sometime within the next 87 months before the 100th anniversary of his passing, voters of every ideology will rededicate America to a great Republican’s object of deep spiritual significance.