Trees in the Triangle: Good for Climate Action and Much More
Andrew Frank & Peter Polonsky Jr.
If you were to ask what trees do for humanity, someone might note that the Amazon is the ‘lungs of the earth’ and reference the life support trees provide through oxygen. But in a time in which climate action is becoming more necessary by the day, it is important to know what trees can do for the climate, especially in the Triangle.
Over the past few years, North Carolina has developed a plan to reduce greenhouse gas emissions primarily by transitioning the state to cleaner energy sources, but the role of trees has largely been overlooked in these plans. Reforestation, such as in urban environments, could play a supplementary role in these plans, and urban planning initiatives could be a mechanism for incentivizing tree-planting.
Of course, beyond their climate benefits, trees are enormously beneficial for public health. For example, strategic placement of trees can help cool the air between 5 and 16 degrees Fahrenheit, which reduces the urban “heat island” effect, i.e., the tendency for cities to be warmer than surrounding areas because of modification of land surfaces (e.g., parking lot pavings). Additionally, large trees filter the air of fine particulates, like dirt, dust and smoke, as well as pollutants like ozone (for which one 2014 study showed significant potential for reforestation to reduce). As a bonus to these public health benefits, planting trees can increase property value and attract tourism and business.
Many casual observers would point out that the Triangle already has significant tree cover. Compared to other cities, this is true. Trees cover roughly 55% of Raleigh and, according to a 2017 tree canopy assessment, 52% of the Bull City, compared to 40% in Virginia Beach and 35% in the District of Columbia. However, the assessment, which was commissioned by the City of Durham, noted that the city’s tree canopy, like that of many cities across the country, is not equitably distributed. For example, many areas along the NC 147 corridor, which are more racially diverse and lower income than the rest of Durham, have less than 33% tree cover, whereas other more affluent neighborhoods, including those around Duke University, enjoy over two-thirds tree cover.
Additionally, the assessment showed that as much as 35% of Durham’s area would be suitable for additional tree canopy. While this land includes areas like baseball and soccer fields, where planting trees would be unpopular to say the least, it includes other spaces, like sidewalks, street medians and oversized parking lots, where trees can and should be planted. Moreover, this potential stands to increase in the coming decades as cities like Durham pursue high-density development and younger people abandon the “urban sprawl” lifestyles of their parents’ generation. In other words, land previously used for large, single-family homes, big-box development, and an extensive highway network may eventually be converted into urban parks and sanctuaries with greater tree cover.
Thankfully, local citizens and governments have realized the importance of trees with several initiatives already in place, including the following.
There are citizen-led initiatives, such as Trees for the Triangle, which plans to plant 50,000 trees by 2050 for many of the benefits detailed above. In addition, Raleigh’s “NeighborWoods” program allows Raleigh residents to request, for free, the planting of trees on city property. There are government-led initiatives, such as Durham’s Urban Forestry Program (which primarily replaces trees) and the NC Forest Development Program (which assists in private forest management). And there are non-profit initiatives, such as the Dogwood Alliance’s Stand4Forests campaign that aims to prevent further deforestation.
Despite these initiatives, an analysis of the global tree restoration potential noted that under a business-as-usual scenario, tree cover in the American Southeast is expected to shrink significantly by 2050 due to climate change, which would lower natural carbon uptake and further exacerbate the effects of climate change. Analysis by the FAO notes that mature trees can absorb around 150 kilograms of carbon dioxide per year. Assuming current efforts maintain constant tree canopy cover in the state, planting 10 additional trees per person could offset about 15%* of the net emissions of North Carolina in 2020.
While ongoing efforts in the Triangle are important, current efforts may not be sufficient in the long-term. Nearly 14 million acres of forest in NC are privately owned and may be subject to development in the absence of renewed emphasis on tree restoration. Restoring and enriching the natural potential of ecosystems in the Triangle to capture carbon is one effective solution which, among a suite of policies, would help mitigate climate change. North Carolina should include reforestation and afforestation efforts in any climate action plan going forward, including the Clean Energy Plan.
* The NC Greenhouse Gas Inventory projects the net emissions of all sectors in the state in 2020 will be about 109.55 million metric tons of carbon dioxide-equivalent. The NC Office of State Budget and Management projects the state population will be 10,630,691 in July 2020. Ten mature trees per person absorbing about 150 kilograms of carbon dioxide per year would reduce net emissions by about 15%.