Gifts That Keep On Giving: How Christmas Trees Could Curb Erosion in Coastal Louisiana, Part I

Editor’s Note: Some of you might have seen an earlier draft of this piece that was mistakenly published several days ago. Please refer to this updated version of the article, as we have removed the earlier edition of this post from our website.

With Christmas trees littering curbsides across the country, you might be wondering whether thrown-away tannenbaums could be put to better use. In this three-part series, we'll examine some of the ways that holiday discards could be salvaged and re-purposed for coastal restoration.

Noël in New Orleans: A Christmas tree, topped by a fleur-de-lis, stands near St. Louis Cathedral in the French Quarter. Over the next few months, thousands of trees like this one will be used in projects to restore Louisiana’s wetlands and beaches. But with municipal and state budget troubles on the horizon, the future of these initiatives remains uncertain (Source: Flickr (quinn.anya))

On a winter’s day in 1510, a guild of merchants living in what is now known as Latvia celebrated Christmas by cutting down a fir tree, garlanding it with decorations, and throwing a party. After the festivities were over, they set the conifer alight and stumbled home in the December darkness.
 
Much has changed in the five hundred years since the first recorded use of a Christmas tree. Today, concerns about carbon emissions and creosote mean that few holiday celebrations end with ceremonial tree burns. Still, the problem of tree disposal remains an issue for town councils in Latvia, Louisiana, and points in between.
       
As a result, we decided to use this post-holiday series – our first of the new year – to consider some of the ways that natural and artificial Christmas trees could be recycled for use in flood defense and coastal restoration. We’ll start by examining the successes and failures of a recently-shelved Louisiana initiative – the Parish Coastal Wetlands Restoration Program (PCWRP) – that used discarded conifers to combat land loss. We’ll then take a look at innovative strategies to incorporate Christmas trees in revetments, and examine how plastics from artificial trees could be re-used to manufacture important components of levees and surge barriers. Finally, we’ll estimate the employment impact of these activities.
 
Band-Aids for the Bird’s Foot
 
The disruption of natural sediment flows from the Mississippi River has been a key factor behind Louisiana land loss in the past century.  The deltaic plains of southeastern Louisiana were formed over the last eight thousand years by the Mississippi, as the river deposited massive amounts of clay, sand, and silt near its mouth on the Gulf of Mexico.

(Click to enlarge) Ghost of Coastlines Past: The map above illustrates the geological history of the lower Mississippi Valley, showing the deltaic lobes formed by sediment deposition over the past eight millennia (kyr = 1,000 years) (Source: Nature Geoscience)

Like the limbs of a tree, distributaries branched off the main trunk of the Mississippi River as it changed course every 1,000 – 2,000 years. This created a succession of expanding and contracting lobes that gave the delta its characteristic “bird’s foot” shape. On balance, the Mississippi River Delta grew because its rate of accretion (stemming from steady flows of river sediment) exceeded the rate of land loss from subsidence and coastal erosion. Where the river met the sea, a rich wetland habitat emerged, creating the swamps and marshes that characterize much of coastal Louisiana.
 
However, a century of navigation and energy infrastructure construction (among other factors) has upset that delicate balance by constraining the Mississippi River and shunting its sediment into the Gulf. These actions have starved Louisiana’s deltaic wetlands of the materials they need to replace land lost to subsidence, storm action, and sea level rise. As a result, thousands of square miles of the Mississippi River Delta have eroded into the Gulf of Mexico.
 
It will be impossible for the varied wetland habitats of southern Louisiana to regain their natural resilience without the reintroduction of cyclical sediment and water flows from the Mississippi River to its delta. This will involve a public works program on a tremendous scale, with massive investments of time, money, and manpower at a time of constrained resources.
 
Against that backdrop, a small-scale program to recycle Christmas trees in restoration efforts might seem superfluous or distracting, like bandaging a broken leg without fixing the injured bone. But just as band-aids can serve as useful precursors to more sophisticated medical treatment, spot programs to bolster vulnerable wetlands – like the construction of protective coastal fences from discarded Christmas trees – may be worth pursuing until large-scale restoration projects like sediment diversions are put in place.
 
With that in mind, let’s look at one of the more famous “band aid” projects of the recent past – the PCWRP.
 
Oh Christmas Tree
 
The Parish Coastal Wetlands Restoration Program (PCWRP), colloquially called the “Christmas Tree Program” in southern Louisiana, was born out of a pilot project at LSU in the late 1980s. Over the next twenty years, it became a program of brush fence installation using natural trees that operated in nearly two dozen parishes.

In this file photo from the Parish Coastal Wetlands Restoration Program, volunteers compact trees into shoreline cribs for sediment trapping (Source: Louisiana Department of Natural Resources)

Proponents of using Christmas trees argue that they are well-suited for protective breakwaters around vulnerable marshes. They are bulky and big, yet easy to move because they weigh so little. Once placed inside brush fences, Christmas trees allow measured movement of water and fine material, helping to encourage sedimentation within a protective pen. The limbs and trunks of the dead trees are organic, and provide an environmentally-friendly habitat for local marine life. While Christmas trees are seasonal, they are plentiful and readily available for brush fence projects during the months after the holiday season.
 
For two decades, discarded boughs of holly and pine were de-tinseled and deposited in wetlands around southern Louisiana. The design and installation of the Christmas tree fences was managed by coastal engineers from the Louisiana Department of Natural Resources (DNR). Within these engineered breakwaters, wave action was reduced, which allowed sediment to collect and build up land, rather than wash away into the Gulf of Mexico. In their small way, these Christmas tree crèches helped to combat coastal erosion in vulnerable stretches of coastal Louisiana. Between 1990, when the Department of Natural Resources launched the initiative, and 2007, more than 1.5 million trees were used to create 40,000 linear feet of protective barriers. According to the DNR, these natural fences protected shallow marshes in nineteen wetland parishes.
 
Most of the trees that were used came from homes in the coastal zone, but donations were sent from as far afield as California. Even commanders-in-chief contributed to the effort, with President Clinton sending fifty trees from the White House in the winter of 1997.

(Click to view video) Arbors Aweigh: In this screenshot from a film about the Christmas tree program, a National Guard helicopter positions bundled trees into place at an artificial sediment barrier near New Orleans (Source: New Orleans Video Access Center)

Louisiana’s PCWRP inspired similar programs along Chesapeake Bay and other threatened coastlines. In addition, stories about “the Christmas tree program” on National Public Radio and in other media outlets helped to increase broader awareness about Louisiana land loss.

However, the PCWRP’s direct impact on reversing coastal erosion was modest. The DNR estimated that only 250 acres were saved or created under the Parish Coastal Wetlands Protection Program, leading some to wonder whether the limited success of the PCWRP justified its annual cost of roughly $150,000. Also, its employment effects were limited, as the program relied heavily on volunteers rather than salaried workers. Lastly, the Christmas tree program did little to spark sustained investment in mitigation measures based on recycled biomass.

Thus, while the PCWRP, as structured, was a good way to spur interest in coastal erosion, that interest failed to translate into action on large-scale projects to restore the Mississippi River Delta. 
 
Last Christmas?
 
In 2005, Louisiana’s coast was hit by Hurricane Katrina and Hurricane Rita. The fences put in place by PCWRP volunteers fared remarkably well in the storms, suffering only minor damage. Unfortunately, the Christmas tree program itself was more severely affected the economic repercussions that followed.
 
In the years after Katrina and Rita, parish participation in the PCWRP began to decline. By the 2007-2008 holiday season, only fifteen parishes were involved in the brush fence program. In some places such as Tangipahoa Parish, local universities or charitable organizations took over fence construction projects with the help of area volunteers, but as budget crises plagued local governments in 2008 and 2009, the PCWRP came ever closer to the chopping block.
 
Earlier this year, the Parish Coastal Wetlands Restoration Program was finally axed from the state budget. Though a few cities, including New Orleans, decided to continue local versions of the Christmas tree program, the DNR suspended its operations in the PCWRP, effectively ending wetland projects with Christmas trees in much of coastal Louisiana.
 
Despite the demise of the PCWRP, there is still potential for innovative “treecycling” programs to contribute to coastal restoration in the Pelican State. In our next post, we’ll consider some of the ways that this might happen.