NOLA: Growing Stronger not Just Bouncing Back

Towering over the streets of New Orleans is one of the country’s oldest and most distinctive urban canopies.  It is an urban forest that includes some of the nation’s grandest trees including the 800 year old McDonogh Oak, the Anseman Oak, the Suicide Oak and the Tree of Life.   These ancient trees are among the oldest living beings on the continent, some predating the city itself.

In 2005 Hurricane Katrina took out over 100,000 trees in the city and an estimated one third of the urban forest was lost. Despite this setback, many trees remain and many have been planted in the 11 years since. Most importantly the trees are healthy, vigorous, and thriving.

For a deeper understanding of why trees in New Orleans are so long lived and vigorous, we need to go underground and back in time back to the Pleistocene period when four successive ice ages caused major shifts in sea levels. This changing coastline left a thick layer of beach sand over much of the southeastern states, in a series of glacial terraces.  Today the city of New Orleans has beach sand reaching 20-30 feet down (source).  This deep layer of sand provides ideal drainage, aeration and root zone for the trees allowing the root systems to grow deep and wide.

Closer to the surface the trees benefit from rich layers of sedimentary deposits. The City of New Orleans is situated on the Mississippi river alluvial plain. Over centuries, nutrient rich sediment has eroded from the fertile lands of the upper Mississippi and deposited throughout the delta. Today, each time the Mississippi embayment floods, trees around New Orleans are drenched with the nutrient rich topsoil running off America’s farms in the Midwest.

Success of the urban canopy in New Orleans is a clear endorsement of the arborists’ mantra “Right Tree Right Place” but it is also the result of careful planning and good management .  The City of New Orleans has worked to protect and preserve its heritage trees, and invested in the planting and maintenance of new trees throughout the city. Ann MacDonald, director of the Department of Parks and Parkways, leads a team of dedicated urban foresters, landscape architects and staff who work with city officials and stakeholders to manage this priceless asset.

The department faces many of the same challenges faced by countless other parks departments in America including how to preserve the tree canopy while balancing the needs of businesses, utility companies and residents.  MacDonald’s team has created strong guidelines for tree protection, tree planting and maintenance, and works with construction companies and utility companies to ensure appropriate measures are taken to protect and preserve trees.

“We are stewards of the public green-space” says MacDonald, “We take that very seriously.”

The Department of Parks and Parkways, works with the city government and advocates for the city’s trees. They respond to resident concerns about sidewalk issues and other challenges of living with mature trees, and they help to educate stakeholders on the value of the urban forest. “The administration and leaders of the city are becoming more engaged and understanding the value of the trees. Citizens are becoming more engaged and aware of the value of the trees than they were ten years ago” says MacDonald.

Since Katrina, the Department of Parks and Parkways has focused on leading a re-greening effort to replant trees in the city. With over 100,000 trees lost to the storm, MacDonald and her team knew they needed to mobilize the community and reach out to local partners and nonprofit groups to maximize their collective impact. The result has been one of the most successful grassroots community tree planting efforts in the country. Together with their partners, the Department of Parks and Parkways have planted over 60,000 trees since Katrina and engaged over 85,000 volunteers along the way.

One of these partners is NOLA Tree Project. The mission of NOLA Tree Project is growing stronger, healthier communities through tree planting, community service, and disaster relief programs.  Over the past 10 years NOLA Tree Project has planted over 37,000 trees through community planting events and programs.

On November 5th the NOLA Tree Project planted 1,200 trees at the Louisiana Nature Center with 200 volunteers in just over two hours. After the event volunteers came together to enjoy food and music. “When you engage a community, and they get in the dirt with you and do something positive like planting trees, it strengthens and unifies the community.” Connie Uddo, executive Director of NOLA Tree Project explains.

“Volunteers understand that what they are doing is going to benefit their community for years and years to come. It is an awesome thing to see people unified around a great purpose and project. This creates community sustainability and a more unified and resilient city.”

These efforts to replant trees is engaging the community and promoting a greater awareness of the benefits of trees to quality of life in New Orleans. “Volunteers get a briefing on what the purpose of each project is and why it is important to plant trees” explains Uddo. “They are educated on how to properly plant and the importance of proper watering and maintenance.  We educate them on the species of trees, on how wildlife benefits from the trees, as well as the environmental benefits, including protecting the coastline from erosion, managing flood waters and lowering temperatures.  People walk away with a broad understanding of the importance and the value that trees bring.”

To continue this process of building awareness around the value of the urban forest, the Department of Parks and Parkways is considering completing a tree survey.  This will involve gathering statistical data on the tree population of the city such as species and variety, tree height and diameter, crown characteristics and location. This data will help MacDonald and her team better manage the trees and quantify the economic value of the urban forest.

Placing an economic value on the benefits that trees provide cities helps to draw attention to the real value of the urban forest and the real cost of losing tree canopy. Tree advocates, urban foresters and public officials like Ann MacDonald, can use this information to communicate effectively with key decision makers in the public and private sector as well as with the residents that share a stake in the urban forest.

Many cities throughout the country have completed tree surveys utilizing the USDA Forest Service i-Tree Eco model. The i-Tree model was developed to help managers and researchers quantify urban forest structure and its functions. Using GIS and a complex set of algorithms, it allows communities and researchers to produce detailed inventories of their urban canopies and calculate its dollar value.

Results can be surprising.  When New York City completed its tree survey, it revealed that the city has about 5.2 million trees with canopies that cover 20.9 percent of the area.  This urban forest stores about 1.35 million tons of carbon valued at $175 million. In addition, New York City trees remove about 42,300 tons of carbon and about 2,202 tons of air pollution each year – services valued at $17.3 million per year. The structural value of New York City’s urban forest is estimated to be $5.2 billion. In Washington DC trees store 525,000 tons of carbon valued at $68 million and remove $2.1 million of carbon and $2.8 million of air pollution each year.  In Houston the annual functional value of the urban forest is estimated to be $465 million and the structural value $205 billion (source).

What is the value of the urban forest in New Orleans?  If the city moves forward with the tree survey, we may soon find out. Whatever the outcome, we can count New Orleans’ urban forest as one of the city’s most valuable assets and one of America’s national treasures. We can also trust that this treasure is in good hands.

Resilience is defined as the ability to recover from adversity. Defined in this way the City of New Orleans is one of America’s most resilient cities. The under-the-radar effort to replant 100,000 trees while preserving the cities heritage trees is another example of the determination, grit, collaboration and commitment that have helped New Orleans not just bounce back in the aftermath of Katrina but grow stronger.